Diagnostics of faults in vehicle components and systems (Mitsubishi Galant 6)

Contents: Diagnosing Engine Starting Problems ⤓ Petrol engines ⤓ Diesel engines ⤓ Diagnosis of problems arising during…⤓ Petrol engines ⤓ Increasing engine speed is not…⤓ Diesel engines ⤓ Diagnosis of the causes of noise,…⤓ Diagnostics of engine electrical…⤓ Diagnostics of malfunctions of the…⤓ Transmission Line Fault Diagnosis ⤓ Automatic transmission ⤓ Manual gearbox ⤓ Clutch ⤓ Differential and final drive ⤓ Transfer case ⤓ Cardan shaft (rear-wheel drive and…⤓ Drive shafts/axle shafts ⤓ Other problems related to the…⤓ Diagnostics of brake system faults ⤓ Diagnosis of wheel, tire, steering…⤓ Wheels and wheel bearings ⤓ Tires ⤓ Steering drive ⤓ Suspension ⤓ Diagnostics of on-board electrical…⤓ Headlights ⤓ Running lights and side lights ⤓ Interior lighting fixtures ⤓ Brake lights ⤓ Control lamps ⤓ Direction indicators hazard warning…⤓ Horn ⤓ Windscreen wipers ⤓ Diagnostics of instrument cluster…⤓ Fuel consumption, engine temperature…⤓ Diagnostics of malfunctions of…⤓ Heater ⤓ Air conditioner ⤓

Vehicle owners who perform routine vehicle maintenance procedures as described in Chapter Settings and ongoing maintenance of this Manual, the schedule will very rarely have to refer to the materials of this Section. The reliability of units and components installed on modern cars is so high that with timely replacement of worn out and failed parts due to aging of materials, the probability of their sudden failure is extremely small. Failures rarely occur spontaneously and are usually a consequence of the sometimes prolonged development of a defect. In particular, the failure of mechanical components is almost always preceded by the emergence and evolution of characteristic symptoms, sometimes manifesting themselves many thousands of kilometers before failure. The same components that can fail unexpectedly are usually not vital for the functioning of the main units and systems of the car, or are easily replaced under road conditions.

The fundamental step in identifying the cause of any failure is choosing where to start looking. Often the cause is obvious, but in some cases it takes some work to do a little investigation. A car enthusiast who has made half a dozen random checks, replacements and repairs has a good chance of finding the cause of the failure (or its symptom), but this approach is not reasonable in any way, due to its labor intensity and the pointlessness of the expenditure of time and money. A calm, logical approach to finding the failed unit or component is much more effective. It is imperative to take into account all the symptoms and warning signs that preceded the failure, sometimes minor ones, such as loss of engine power, changes in meter readings, the occurrence of unusual sounds and smells, etc. Do not forget that the failure of components such as fuses or spark plugs may be only a symptom of a more deeply hidden problem.

Below in this subsection is a fairly simple diagnostic scheme for the most common failures. The causes of failures and their symptoms are grouped according to their relation to the functioning of a specific unit or system: "Engine", "Cooling system", etc.

Regardless of the nature of the failure, the same basic principles always form the basis for investigating its cause:

Make sure you have correctly identified the symptoms of the failure. This means being sure that you have defined the boundaries of the search area, which is especially important when helping another motorist diagnose a failure who cannot adequately describe the symptoms of the problem.
Try not to overlook obvious violations. For example, if the engine does not start, do not hesitate to check the fuel in the gas tank (however, do not take the claims of the owner of the faulty car at face value). In the event of electrical equipment failure, first of all, you should check the condition and reliability of the fastening of the terminal connections of the electrical wiring, only after that does it make sense to get out the diagnostic devices.
Try to eliminate the cause of the failure, not its symptom. Replacing a discharged battery with a new one will help start the engine, but the existing cause of the old battery discharge will remain unresolved, which will lead to a quick failure of the new one. Also, replacing spark plugs covered in oil will restore the engine's proper functioning for some time, but the failure will certainly reoccur soon (if the cause was not simply the use of the wrong type of spark plugs).
Do not take any statements at face value. Remember that a "new" component may also be faulty, especially if it has been lying in the trunk for a long time - do not exclude a component from the list of checks just because it is new or recently installed. If you neglect to follow this recommendation, do not be surprised when the cause of the failure is finally identified and is obvious from the very beginning.

Diagnosing Engine Starting Problems

Petrol engines

The engine turns over but does not start

1. The fuel tank is empty. Check and refuel if necessary.

2. The battery is discharged (the engine turns over too slowly). Check and, if necessary, recharge or replace the battery.

3. The battery terminals are oxidized or the wire tips are loose. Clean the contact surfaces, replace worn or damaged components.

4. Fuel is not supplied to the injection injectors. Check the condition of the fuel pump, the corresponding electrical wiring, fuse and relay.

5. There is excessive wear or mechanical damage to the internal components of the SAG. Measure the compression pressure in the cylinders, assess the condition of the timing drive components, valve guides and stems, check the valve clearances.

6. Water has entered the fuel. In cold weather, crystallization of moisture contained in the fuel can lead to blockage of the fuel lines. The use of special additives can facilitate starting the engine, but then it is recommended to drain the system and flush it with fresh fuel.

7. There is a malfunction of the ignition system. Check the condition of the relevant electrical wiring and the reliability of its contact connections. Assess the degree of wear of the spark plugs and the correct installation of the interelectrode gaps. If the situation is aggravated by increased humidity, check for a short circuit between the spark plugs and ignition coils.

8. The engine management system is not functioning properly. Check the condition of the relevant sensors and the system control module.

The engine does not turn over when trying to start it

1. If the brightness of the instrument panel backlight lamps decreases significantly when the engine is turned over with the starter, evaluate the condition and charge level of the battery, check the proper functioning of the generator. Evaluate the quality of the contact connections of the corresponding electrical wiring. Measure the output voltage of the generator. Make appropriate corrections, replace the failed components.

2. The starter circuit disconnect switch (MT)/start enable switch (AT) is faulty. Make sure that the clutch pedal is fully depressed (MT) - on some models the starter circuit disconnect switch is subject to adjustment. Check that the selector lever is set to the "P" or "N" position (AT) without any problems. Assess the condition of the wiring of the corresponding switch and its contact connectors. Make the necessary corrections, replace the faulty components.

3. The starter is not functioning properly. Check the condition of the electromagnetic starter and the starter relay. Assess the quality of the contact connections of the corresponding electrical wiring. Check the proper grounding of the unit to the chassis ground. If battery voltage is present on the relay, try to perform a test run using the remote starter. Make the necessary corrections, replace the failed components.

4. The engine is seized. If the car has not been used for a long time, there is a fairly high probability of piston rings "sticking" to the cylinder mirrors as a result of surface corrosion. Another possible reason for the engine to be seized is the formation of hydraulic plugs as a result of moisture being sucked in. Remove the spark plugs and try to turn the engine with a wrench on the crankshaft pulley bolt, reasonably measuring the force applied. If there is a seizure, try to identify and eliminate its cause.

The engine starts but immediately stalls

1. The ignition switch is faulty. Assess the condition of the contact elements in the RUN position of the key. Repeat the start attempt, having previously disconnected all on-board power consumers. Sometimes, if the key is worn out, it is enough to turn it back and forth several times - replace the key at the first opportunity.

2. The ignition system circuit wiring is broken or otherwise damaged, or the terminals of its contact connections are loose. Perform the appropriate check, make the necessary corrections, replace the defective components.

3. There is a loss of vacuum in the intake manifold. Assess the condition of the relevant vacuum hoses, make the necessary corrections, replace defective components.

4. There is a deviation from the norm of the pressure-flow characteristic of the fuel pump. An excessive drop in the pressure developed in the fuel system is usually accompanied by a noticeable decrease in the vehicle's responsiveness during acceleration. Check the patency of the fuel lines. The fuel pump is not subject to adjustment and must be replaced in case of failure.

5. The injection/engine control systems are not functioning properly. Assess the condition of the wiring and contact connections of the relevant information sensors and control module.

6 The patency of the exhaust system tract is impaired. Check and eliminate any detected faults.

The starter is difficult to engage or is accompanied by extraneous noises

1. The starter drive pinion teeth are broken, worn or jammed. Check and make any necessary corrections.

2. The flywheel ring gear is worn or damaged. Remove the inspection window cover and visually inspect the flywheel.

When turning the engine, the starter makes extraneous noises

1. The starter drive pinion or flywheel ring gear is damaged. Check and make any necessary corrections.

2. The starter fasteners are loose, or the housing is mechanically damaged. Check, tighten the fasteners, replace the faulty starter.

Difficulty starting a cold engine

1. The battery is discharged, or there is a deviation from the norm of the volt-ampere characteristic of the starter electric motor. Recharge the battery or replace the starter.

2. The battery terminals are oxidized or the wire tips are loose. Check, make the necessary corrections, clean the terminals, replace the defective components.

3. The fuel system is not functioning properly. Evaluate the pressure developed by the fuel pump, check the patency of the injection injectors. Replace the failed components.

4. The engine's initial settings are out of order. Perform the appropriate checks, assess the condition of the spark plugs and the correct setting of the interelectrode gaps. On models with manual valve clearance adjustment, perform the appropriate check and make the necessary adjustments if necessary.

5. The coolant temperature sensor is faulty. Perform the appropriate check, and replace the faulty sensor if necessary.

6. The injection/engine control systems are not functioning properly. Assess the condition of the wiring and contact connections of the relevant information sensors and control module. Make appropriate corrections or replace defective components.

The article is reprinted from this source (MitsubishiMan.ru)

Difficulty starting a hot engine

1. The air cleaner filter element is dirty or its patency is otherwise impaired. Replace the filter, check the patency of the air intake tract.

2. The engine grounding is faulty. Assess the quality of the relevant contact connections, make the necessary corrections, replace the defective components.

3. The engine requires maintenance. Check the correctness of the initial settings. Assess the proper functioning of the lubrication, power supply and engine control systems.

Diesel engines

The engine turns over but does not start

1. The fuel tank is empty. Check and refuel if necessary.

2. The vehicle is filled with low-grade diesel fuel. Check, if necessary, empty the fuel tank and flush it and fill it with quality fuel.

3. The compression pressure in the cylinders has dropped. Perform the appropriate check; if necessary, perform a restorative repair of the unit.

4. The valve timing of the high-pressure fuel pump is not set correctly. Check the pump adjustment and make the appropriate adjustments if necessary.

5. The fuel injection pump is faulty. Check the condition of the pump, replace it if necessary. Make sure the new pump is adjusted correctly.

6. The injectors are not functioning properly. Check and replace defective components.

The engine does not turn over when trying to start it

2. The starter circuit disconnect switch (MT)/start enable switch (AT) is faulty. Make sure that the clutch pedal is fully depressed (MT) - on some models the starter circuit disconnect switch is subject to adjustment. Check that the selector lever is set to the "P" or "N" position (AT) without any problems. Assess the condition of the wiring of the corresponding switch and its contact connectors. Make the necessary corrections, replace the faulty components.

3. The starter is not functioning properly. Check the condition of the electromagnetic starter and the starter relay. Assess the quality of the contact connections of the corresponding electrical wiring. Check the proper grounding of the unit to the chassis ground. If battery voltage is present on the relay, try to perform a test run using the remote starter. Make the necessary corrections, replace the failed components.

4. The engine is seized. If the car has not been used for a long time, there is a fairly high probability of piston rings "sticking" to the cylinder mirrors as a result of surface corrosion. Another possible reason for the engine to be seized is the formation of hydraulic plugs as a result of moisture suction. Remove the injectors and try to turn the engine with a wrench on the crankshaft pulley bolt, reasonably measuring the force applied. If there is a seizure, try to identify and eliminate its cause.

The engine starts but immediately stalls

1. The fuel return line or its check valve is blocked. Perform the appropriate checks, eliminate the causes of the line blockage, and replace the defective components if necessary.

2. Glow plugs are cut off too early. Check and make necessary corrections.

3. The fuel injection pump adjustment is broken. Check the valve timing and make the necessary adjustments.

4. The vehicle is filled with low-grade diesel fuel. Check, if necessary, empty the fuel tank and flush it and fill it with quality fuel.

5. The compression pressure in the cylinders has dropped. Perform the appropriate check; if necessary, perform a restorative repair of the unit.

6. There are air locks in the fuel system. Check the fuel level in the fuel tank and refuel if necessary.

7. The fuel injection pump is faulty. Check the condition of the pump, replace it if necessary. Make sure the new pump is adjusted correctly.

The starter is difficult to engage or is accompanied by extraneous noises

1. The starter drive pinion teeth are broken, worn or jammed. Check and make any necessary corrections.

2. The flywheel ring gear is worn or damaged. Remove the inspection window cover and visually inspect the flywheel.

When turning the engine, the starter makes extraneous noises

Diagnosis of problems arising during engine operation

Petrol engines

Idle speed stability is impaired

1. The ignition system is not functioning properly. Check the condition of the system components and the correctness of the adjustments. Make the necessary adjustments, replace the defective components.

2. The injectors are not flowing properly. Check and replace defective components.

3. Fuel pump performance has dropped. Check the fuel lines for patency, replace the pump if necessary.

4. The engine management system is not functioning properly. Check and make necessary corrections.

The engine power has dropped

1. The primary engine settings are not correct. Perform the appropriate checks, assess the condition of the spark plugs and the correct setting of the interelectrode gaps. On models with manual valve clearance adjustment, perform the appropriate check and make the necessary adjustments if necessary.

2. The air cleaner filter element is dirty or its patency is otherwise impaired. Replace the filter, check the patency of the air intake tract.

3. The injection/engine control systems are not functioning properly. Assess the condition of the wiring and contact connections of the relevant information sensors and control module. Make appropriate corrections or replace the defective components.

4. The pressure developed by the fuel pump has dropped. Check the pressure in the fuel system tract, perform the necessary repairs, replace defective components.

5. The throttle drive components are not adjusted correctly. Check the completeness of the throttle opening, assess the degree of wear of the drive rotary unit bushings. Replace the defective components.

6. The patency of the exhaust system tract is impaired. Inspect the system components for deformations and other mechanical defects. Compare the temperature at the input and output of the catalytic converter and muffler - if the temperature of the incoming flow is much higher than the temperature of the output, then the patency of the corresponding component is impaired.

7. The knock sensor is faulty or too loose. Failure to tighten the sensor properly may result in ignition delay and, as a result, a decrease in engine power. Assess the condition of the sensor, check its tightening force, and replace it if necessary.

8. There is an internal mechanical defect of the engine (decrease in compression pressure, wear of piston rings, valves, camshafts and timing components). It is necessary to carry out a restorative repair of the power unit.

9. Engine oil level too high. Check and adjust accordingly. Replace oil and oil filter if necessary.

10. There is a loss of vacuum in the intake manifold or connecting vacuum lines. Assess the condition of the components, replace defective gaskets/hoses.

11. Clutch slips. Check the condition of the clutch assembly components.

12. Brakes are "stuck". Check and make necessary corrections. Replace defective components.

13. Excessively worn or incorrectly inflated tires. Check and make adjustments if necessary. Replace tires if necessary, making sure that their wear is not related to wheel alignment/suspension or body geometry violations - such violations can cause an increase in the friction coefficient and, as a result, a decrease in engine efficiency.

14. Low-octane gasoline was used to refuel the car. Fill the fuel tank with quality fuel.

Excessive fuel consumption

1. The air cleaner filter element is dirty or its patency is otherwise impaired. Replace the air filter.

2. The primary engine/ignition and fuel system settings are not correct. Assess the condition of the ignition system components, replace worn parts. Check the correct setting of the ignition timing angle and the adjustment of the air-fuel mixture quality.

3. The wheels are the wrong size, the tires are not inflated correctly, or their tread is excessively worn. Installing oversized wheels increases their resistance to turning. To maintain normal speed, a vehicle equipped with undersized wheels requires higher engine speeds. Excessive tread wear may be due to incorrect tire inflation, incorrect wheel alignment angles, or incorrect suspension geometry. All of these phenomena lead to increased fuel consumption due to increased engine load under the same vehicle operating conditions.

4. Brakes are "stuck". Check and make necessary corrections. Replace defective components.

Engine continues to run after ignition is turned off (diesel effect)

1. Idle speed is set too high. Check and adjust accordingly.

2. The idle speed stabilization valve is not functioning properly. Check and replace the defective valve.

3. The ignition timing angle setting is incorrect. Check the condition of the relevant information sensors and other components of the ignition system. Replace defective elements.

4. There is a loss of vacuum in the intake manifold or connecting vacuum lines. Assess the condition of the components, replace defective gaskets/hoses.

5. There is excessive carbon formation in the combustion chambers. Use special fuel additives or disassemble and decarbonize the cylinder head.

6. The power supply/engine control system is not functioning properly. Check the condition of the relevant information sensors and control modules. Replace defective components.

During acceleration or when the engine load increases, knocking noises occur, caused by too early ignition or detonation

1. Low-octane gasoline was used to refuel the car. Fill the fuel tank with quality fuel.

2. The ignition timing is incorrect. Check the condition of the relevant information sensors and other components of the ignition/engine management system. Replace defective components.

3. There is excessive carbon formation in the combustion chambers. Use special fuel additives or disassemble and decarbonize the cylinder head.

4. Non-standard spark plugs are installed. Replace the spark plugs, ensure that the interelectrode gaps are set correctly.

Note: When operating the vehicle at high speeds, it is better to install "colder" spark plugs.

5. The power supply/engine control system is not functioning properly. Check the condition of the relevant information sensors and control modules. Replace defective components.

6. The patency of the exhaust system tract is impaired. Inspect the system components for deformations and other mechanical defects. Compare the temperature at the input and output of the catalytic converter and muffler - if the temperature of the incoming flow is much higher than the temperature of the outgoing flow, then the patency of the corresponding component is impaired.

7. The knock sensor is faulty or too loose. Failure to tighten the sensor properly may result in ignition delay and, as a result, a decrease in engine power. Assess the condition of the sensor, check its tightening force, and replace it if necessary.

Increasing engine speed is not accompanied by an increase in vehicle speed

1. Clutch "slips" (manual transmission). See the subsection below on diagnosing clutch faults.

2. The transmission (AT) is "slipping". Check the level and condition of the ATF in the gearbox. If necessary, make the appropriate adjustments. If the ATF emits a clearly audible burning smell, then the cause of the problem is slipping of the internal components of the transmission. Replacing the ATF and filter can temporarily correct the situation. At the first opportunity, you should perform a restorative repair or replace the AT.

Diesel engines

Idle speed stability is impaired

1. The fuel injection pump adjustment is broken. Check and make the necessary adjustments.

2. There are air locks in the fuel system. Check the fuel level in the fuel tank, refuel if necessary. Check the fuel lines for leaks, perform the necessary repairs.

3. The fuel filter or fuel supply and return lines are clogged. Check the condition of the fuel line, replace defective components.

4. The vehicle is filled with low-grade diesel fuel. Check, if necessary, empty the fuel tank and flush it and fill it with quality fuel.

The engine power has dropped

1. The air cleaner filter element/intake air lines are clogged. Check the condition of the components. Replace the air filter/defective lines if necessary.

2. The fuel injection pump adjustment is broken. Check and make the necessary adjustments.

3. The exhaust system is blocked. Check the condition of the exhaust components. Eliminate any problems found.

4. The fuel filter is clogged. Check and replace if necessary.

5. The ventilation system of the fuel tank filler cap is blocked. The presence of a blockage is indicated by a characteristic hissing sound that occurs when opening the cap. Replace the cap if necessary.

6. The patency of the fuel system components is impaired. Check, make the necessary corrections, replace the defective elements.

7. The compression pressure in the cylinders has dropped. Perform the appropriate check. Make sure there are no external leaks (e.g. through glow plugs and fuel injection nozzles). If necessary, perform a restorative repair of the unit.

Diagnosis of the causes of noise, odors and vibrations that occur during engine operation

During acceleration or when the engine load increases, knocking noises occur, caused by too early ignition or detonation

1. Low-octane gasoline was used to refuel the car. Fill the fuel tank with quality fuel.

2. The ignition timing is incorrect. Check the condition of the relevant information sensors and other components of the ignition/engine management system. Replace defective components.

3. The knock sensor is faulty or too loose. Failure to tighten the sensor properly may result in ignition delay and, as a result, a decrease in engine power. Assess the condition of the sensor, check its tightening force, and replace it if necessary.

4. Non-standard spark plugs are installed. Replace the spark plugs, ensure that the interelectrode gaps are set correctly.

Note: When operating the vehicle at high speeds, it is better to install "colder" spark plugs.

5. There is excessive carbon formation in the combustion chambers. Use special fuel additives or disassemble and decarbonize the cylinder head.

6. The power supply/engine control system is not functioning properly. Check the condition of the relevant information sensors and control modules. Replace defective components.

7. The patency of the exhaust system tract is impaired. Inspect the system components for deformations and other mechanical defects. Compare the temperature at the input and output of the catalytic converter and muffler - if the temperature of the incoming flow is much higher than the temperature of the outgoing flow, then the patency of the corresponding component is impaired.

A high frequency squealing or whistling noise occurs when the engine is running

1. The accessory drive belts are worn out or their tension has weakened. Check, make the necessary adjustments, replace worn belts.

2. The auxiliary belt tensioner bearings are worn or seized. Check the tensioners and replace the components if necessary.

3. The water pump is faulty. The pump may not leak, which does not exclude the possibility of bearing wear or loose/seized rotors. Replace the pump.

When the engine is running, a metallic grinding noise occurs

1. The water pump is faulty or its mounting bolts are loose. Check the tightening force of the fasteners, replace the faulty pump.

2. The auxiliary belt tensioner bearings are worn or seized. Check the tensioners and replace the components if necessary.

During engine operation, various types of knocking noises occur

1. The hydraulic valve clearance correctors in the tappets are not functioning properly (on models with the corresponding configuration). Check the level and condition of the engine oil. If necessary, replace the oil and oil filter. Check whether the tappets have collapsed. Replace the defective components. In addition, the proper functioning of the hydraulic tappets depends on the engine oil pressure - check the patency of the oil filter, the condition of the oil pump and its pressure reducing valve.

2. On models with manual valve clearance adjustment, check the installation of the latter and assess the degree of wear of the timing components. If necessary, make the appropriate adjustments and replace the failed parts.

3. Timing belt/chain is worn or incorrectly adjusted. Check, make necessary adjustments, replace defective drive components.

4. The intake or exhaust valve stems are deformed or otherwise damaged. Remove the cylinder head, check the condition of the valve assembly components, replace defective parts.

When the engine is running, a loud dull knocking noise occurs

1. The crankshaft pulley or flywheel has become loose. Check, replace the mounting bolts and tighten them to the required torque.

2. As a result of hydraulic blocking, the connecting rod(s) has been deformed. The necessary restorative repair of the power unit should be carried out.

3. Excessively worn or damaged connecting rod bearings - this type of situation most often occurs as a result of reduced oil pressure. Perform appropriate engine repair.

When the engine is running, a distinct smell of gasoline is present in the passenger compartment and near the vehicle

1. Check the fuel level - overfilling the tank can lead to minor fuel leaks through the filler neck. The smell should disappear already in the first 20-25 km of running as a result of purging the carbon adsorber.

2. The fuel tank filler cap is not tight enough. Check, tighten the cap, and replace it if necessary.

3. The clamps securing the fuel supply or return line hoses of the fuel system path have become loose. Check the reliability of the clamps, and replace them if necessary. It is also possible that the sealing glands of the active components of the fuel system are out of order. Check and replace any defective seals.

4. Assess fuel economy. If the increase in consumption is due to the failure of any components or to a malfunction of the air-fuel mixture ignition, the catalytic converter may become contaminated. Usually, the driver is warned of such situations by the activation of the "Check Engine" indicator lamp. Check the condition of the spark plugs or conduct an exhaust gas analysis. Replace faulty spark plugs and failed fuel system components.

When the engine is running, a smell of hydrogen sulfide (rotten eggs) occurs near the car

1. As a result of feeding the lean mixture into the combustion chambers, the catalytic converter overheats, in which an irreversible chemical reaction occurs with the release of hydrogen sulfide. Check the condition of the sealing gasket and vacuum lines of the intake tract, make the necessary corrections.

2. As a result of malfunction of the generator or voltage regulator, the battery is constantly overcharged, accompanied by boiling of the electrolyte. Carefully inspect the battery case for cracks, swelling and other damage. If necessary, remove the battery and thoroughly wash the surface of the support tray with baking soda before installing a new one. Check the proper functioning of the generator/voltage regulator, carry out the necessary repairs or replace the failed components.

When the engine is running, a sweetish smell is emitted near the car

1. There are external coolant leaks. Check the condition of the radiator cap, seals and gaskets of the cooling system components, assess the reliability of tightening the hose clamps. Tighten the fasteners, replace the failed components.

2. There are coolant leaks through the radiator, expansion tank or heater heat exchanger. Carefully inspect the radiator and expansion tank, check for any leaks on the carpets under the dashboard.

3. As a result of internal leaks, coolant enters the combustion chambers, which is usually accompanied by the release of thick white smoke/steam in the exhaust. This type of situation can occur as a result of the destruction of the cylinder head gasket, as well as the appearance of cracks in the body of the block/cylinder head. Additional symptoms of internal coolant leaks include the formation of a whitish coating on the inner surface of the engine oil filler cap, as well as deformation or swelling of the radiator hoses.

When the engine is idling, strong vibrations occur

1. The fastening of the power unit suspension supports has become loose, or their rubber cushions are worn out. Check the condition of the supports, tighten the fasteners, replace the failed components.

2. The crankcase protection elements are deformed or their fastening has become loose. Check, tighten the fastening, restore the original shape of the protective plates.

The intensity of vibrations increases during acceleration

1. Rubber hangers of exhaust system support elements are damaged or lost. Check and replace defective components.

2. The exhaust system sections are not correctly laid out. Assess the adequacy of the laying, ensure that the exhaust system components do not come into contact with the body parts and suspension elements.

Diagnostics of engine electrical equipment faults

The battery discharges while driving

1. The battery does not hold a charge. A decrease in the electrolyte level in the jars may occur as a result of overcharging the battery. Check the proper functioning of the generator/voltage regulator, perform the necessary restorative repairs, or replace the failed components.

2. The quality of the electrical contact on the terminal connections of the battery wires is impaired. Check the condition of the battery terminals and the terminal tips of the wires, carefully clean the contact surfaces, and ensure that the tips are securely seated and fastened to the terminals.

3. The generator/voltage regulator is not functioning properly. Check, perform the necessary repairs, or replace the faulty components.

4. The terminal connections of the electrical wiring on the generator have become loose, the quality of grounding is poor, or the contact terminals are excessively oxidized. Check the condition of the contact connections, clean the terminals, replace the faulty components.

5. The alternator drive belt is worn out or its tension has weakened. Check, tighten or replace the belt, replace defective tensioner components.

The battery discharges during the night parking of the car

1. The battery is faulty. Replace the battery with a known good one.

2. There are electrical leaks. Check the serviceability of the switch-off of all lighting and signaling devices (both external and internal), if necessary, replace the faulty sensor switches.

3. The generator diode assembly components are out of order. Check and replace the defective generator.

Tips for diagnosing engine performance issues

First of all, it is necessary to assess the general mechanical condition of the power unit.

The operation of the fuel supply management system on injection models is based on constant monitoring of the air-fuel mixture supply, based on the continuous transmission of data from the information sensors to the control module. Unlike carburetor models, where the energy developed by the flow of air sucked into the engine is used to push fuel through the metering jets in order to ensure the required composition of the combustible mixture, on models equipped with an injection system, the quality of the mixture is controlled by controlling the duration of opening of the injectors through which the fuel is supplied to the pipeline/intake ports of the combustion chambers.

Control is performed based on the analysis of data continuously received from the corresponding information sensors. The sensors monitor such parameters as the operating temperature of the coolant, the temperature and amount of air sucked into the engine, crankshaft speed, the current position of the throttle valve, etc. The control unit continuously analyzes the incoming information and determines the required duration of opening of the injection injectors at the current moment. The sensors generate low-voltage signals, due to which a violation of the quality of the contact connections of the electrical wiring of the corresponding connecting circuits can have a very direct effect on the efficiency of the engine (comparable to the effect caused by the failure of the sensors).

When diagnosing failures related to the proper functioning of the injection system, always first check the condition of the corresponding electrical wiring and its contact connections. Ensure that electrical connectors are securely fastened and periodically check their physical condition. Try not to use chemicals not approved by vehicle manufacturers to clean the surfaces of components and electrical wiring of the control system - after using such products, a film may remain on the surface of the components being cleaned, the presence of which is unacceptable, and there is a high risk of damaging the insulation of the electrical wiring.

The engine electrical system supplies power to all on-board consumers, electronic control units, information sensors and actuators. Due to the extreme sensitivity of the engine control system elements to voltage fluctuations, malfunction of the generator/voltage regulator may lead to a noticeable decrease in the efficiency of the power unit. The vehicles considered in this Manual are usually equipped with generators with a built-in voltage regulator. The operating parameters of such regulators are not subject to adjustment and in the event of malfunctions, the corresponding element (regulator or generator) must be replaced as a whole.

The operation of the ignition system is also closely linked to the operation of the fuel injection/engine management system and is based on the control module using data from the corresponding information sensors. Based on the analysis of the information received from the sensors, the control module makes timely adjustments to the ignition timing, achieving optimal engine operation at any speed and current loads. In most modern systems of this kind, manual adjustment of the ignition timing is no longer possible. In the event of a malfunction of such a system, the failed element is subject to replacement - first make sure that the failure is not associated with damage to the electrical wiring or loosening of its contact connectors. Periodically check the condition of the electrical connectors, if necessary, treat them with patented cleaners.

Diagnostics of cooling system faults

Note. Some problems with the cooling system may also be caused by mechanical failures of the power unit. Thus, a breach in the integrity of the cylinder head gasket or the formation of porosity in the block casting, as a rule, inevitably lead to the development of coolant leaks.

The operation of some cooling systems is based on the use of electrically driven fans. When diagnosing failures of such systems, do not forget to check the condition of the corresponding fuses and the quality of the contact connections of the fan control circuits. Monitor the condition of the terminal connectors, periodically remove corrosion products from the contact surfaces, using only patented specialized cleaners for this purpose.

The engine is overheating

1. The coolant level has dropped. Turn on the interior heater to maximum capacity to check the tract for air locks. "Pump" the cooling system and inspect its components for signs of leaks. Add the required amount of coolant of the required grade to the system.

2. There are weak leaks in the cooling system tract. Perform a pressure test of the tract - the leaks can be identified by ear by a characteristic hissing sound. Particular attention should be paid to the condition of such components as the connecting hoses (with fastening clamps), the coolant supply control valve to the heater heat exchanger, the heater heat exchanger (radiator) itself, the radiator, radiator hoses and the water pump. Replace defective elements, add the required amount of coolant of the required grade to the system.

3. The electrical control device for the cooling system fans is faulty (on models with the corresponding configuration). Check the condition of the corresponding fuses, relays and temperature sensors. Replace the faulty components.

4. There are coolant leaks through the cylinder head gasket, or as a result of the development of porosity in the walls of the block or cylinder head casting. Check and replace the gasket or the defective section of the power unit.

5. The radiator heat exchanger is clogged. Flush or replace the radiator.

6. The water pump is faulty. If the coolant circulation is inadequate, check the tightness of the water pump rotors; if any weakness is detected, replace the pump.

The engine coolant level is constantly dropping

1. There are weak leaks in the cooling system tract. Perform a pressure test of the tract - the leaks can be identified by ear by a characteristic hissing sound. Particular attention should be paid to the condition of such components as connecting hoses (with fastening clamps), the coolant supply control valve to the heater heat exchanger, the heater heat exchanger (radiator) itself, the radiator, radiator hoses and the water pump. Replace defective elements, add the required amount of coolant of the required grade to the system.

2. There are coolant leaks through the cylinder head gasket, or as a result of the development of porosity in the walls of the block or cylinder head casting. Check and replace the gasket or the defective section of the power unit.

Engine overcooling occurs

1. The thermostat is faulty. Replace the thermostat that is stuck open.

2. The electrical control device for the cooling system fans is faulty (on models with the corresponding configuration). Check the condition of the corresponding fuses, relays and temperature sensors. Replace the faulty components.

3. The temperature meter readings are inaccurate. Check the condition of the temperature sensors and eliminate any problems that have been identified.

The engine is running overheated

1. The radiator heat exchanger is clogged. Flush or replace the radiator.

2. The water pump drive belt is worn out or its tension has weakened. Check, tighten or replace the belt, replace defective tensioner components.

3. The cooling system fans are not functioning properly. Check the condition of the drive motors, relays and temperature sensors. Replace defective components.

4. The temperature meter readings are inaccurate. Check the condition of the temperature sensors and eliminate any problems identified.

5. The coolant level has dropped. Turn on the interior heater at maximum capacity to check the tract for air locks. "Pump" the cooling system and inspect its components for signs of leaks. Add the required amount of coolant of the required grade to the system.

Diagnostics of malfunctions of the exhaust system

Note: Do not neglect the increased vibration level associated with faults in the exhaust system. Remember that increased vibration background leads to premature wear of the components of the powertrain suspension mounts, cracks and fatigue deformation of the metal components of the frame and suspension, destruction of welds and the core of the catalytic converter.

There is a characteristic dull knock when the engine is idling

1. The components of the powertrain suspension supports are worn out. Inspect the support units, replace the failed components, tighten the fasteners.

2. The components of the suspension supports of the exhaust system elements are faulty. Inspect the support units, replace the faulty components, install new ones instead of the lost ones.

3. There is mechanical damage to the muffler or catalytic converter. It should be borne in mind that the torn off internal elements of these components can be carried down the tract by the exhaust gas flow, producing characteristic sounds quite far from the defective unit. Such situations can also lead to a violation of the patency of the exhaust tract, which is usually accompanied by a decrease in the depth of vacuum in the engine intake manifold. Remove the suspected sections of the exhaust system, remove all loose and foreign objects from the tract, replace the failed components.

4. Check the correct routing of the working sections of the exhaust system, paying particular attention to the adequacy of the gaps between the system elements and the body/suspension components.

Vibrations of exhaust system components occur while driving

1. The components of the suspension supports of the exhaust system elements are faulty. Inspect the support units, replace the faulty components, install new ones to replace the lost ones.

2. The correctness of the layout of the working sections of the exhaust tract is violated. Assess the adequacy of the gaps formed between the system elements and the body/suspension components.

The exhaust system sections are hung too low under the vehicle

1. The components of the suspension supports of the exhaust system elements are faulty. Inspect the support units, replace the faulty components, install new ones to replace the lost ones.

2. The correct layout of the working sections of the exhaust tract is violated.

The operation of the exhaust system is accompanied by excessive noise background

1. The reliability of the exhaust system components is compromised, or there are exhaust gas leaks. Carefully inspect the entire length of the system, eliminate any detected faults, and replace defective components.

2. Internal partitions of exhaust tract mufflers are damaged. Check condition of suspected components, replace defective units.

3. The failed muffler was replaced with a tubular section due to careless or hasty repairs. Study the technical documentation for the exhaust system, complete all sections of the tract with standard components.

Transmission Line Fault Diagnosis

Automatic transmission

Note. On many models, the AT is controlled electronically. In this case, the condition of the electrical wiring and contact connections of the corresponding circuit is of primary importance. Do not forget to inspect the corresponding components from time to time, check the reliability of the connectors. Use only patented cleaning agents to wipe the insulation and remove oxidation products from the contact terminals of the electrical wiring!

Smoothness of AT shifting is disrupted

1. The transmission fluid level has dropped. Check and make adjustments if necessary.

Attention! Use only the recommended grade of ATF!

2. Check the condition of the ATF. If signs of contamination are detected, replace the fluid and the AT filter. The presence of a burning smell in the fluid indicates slippage of the internal components of the transmission. It is better to entrust the inspection of the condition and restoration of the AT to car service specialists.

3. The AT filter is installed incorrectly or its sealing gasket is damaged. Check, make necessary corrections, replace defective components.

4. The tightness of the sealing gaskets or pressure lines/their nipple connections is broken. Check the condition of the hydraulic tract components of the AT, make the necessary corrections, replace the defective components.

5. The AT/throttle valve shift linkage has become loose. Check, make any necessary corrections, tighten the fasteners.

The AT switching function is faulty

1. The AT shift drive rods are loose/out of adjustment. Check and make the necessary corrections/adjustments.

2. The transmission fluid level has dropped. Check and make adjustments if necessary.

Attention! Use only the recommended grade of ATF!

3. There is damage to the internal components of the transmission. It is better to entrust the inspection of the condition and restoration repair of the AT to car service specialists.

Automatic transmission does not switch to a lower gear when the gas pedal is pressed to the floor

1. Sensors or control units are faulty (models with electronic control AT). Check, make necessary corrections, replace defective components.

2. The adjustment of the kickdown drive rods is disturbed, or the vacuum servo drive is faulty (models with a mechanical kickdown drive). Check the condition of the drive components, make the necessary corrections, replace defective components.

3. On models with electronic control.

4. The diaphragm spring has "sagged" (see Chapter Clutch and transmission line).

5. There are hydraulic fluid leaks from the clutch master or slave cylinder (see Chapter Clutch and transmission line).

6. Air has entered the hydraulic circuit of the clutch drive (the pedal stroke is soft) (see Chapter Clutch and transmission line).

7. The sealing cuff of the piston of the master or slave cylinder is damaged (see Chapter Clutch and transmission line).

8. There is a lack of lubrication in the guide bearing (see Chapter Clutch and transmission line).

Manual gearbox

Gear shifting is accompanied by a grinding noise

1. Clutch release drive components are worn. On models with mechanical or cable clutch drive, check the adjustment of the corresponding components. Adjust the clutch pedal so that its free travel does not exceed 25 mm. On models with hydraulic clutch drive, check the working fluid level in the master cylinder reservoir and make the appropriate adjustments if necessary.

2. Synchronizers are worn out. Remove the gearbox, replace the synchronizers.

3. The synchronizer sliding clutches are worn out. Remove the gearbox, replace the sliding clutches.

4. The gear dogs are worn or damaged. Remove the gearbox and replace the corresponding gears.

The gearbox "jumps" out of the selected gear

1. The shift rod locking springs are worn out. Replace the defective components.

2. The synchronizer sliding clutches are worn out. Remove the gearbox, replace the sliding clutches.

3. The gear dogs are worn or damaged. Remove the gearbox and replace the corresponding gears.

4. The crankshaft thrust bearings are worn out. Disassemble the engine and replace the faulty components.

Difficulty shifting gears

1. The clutch adjustment is out of adjustment. Check and make adjustments if necessary.

2. Synchronizers are worn out. Remove the gearbox, replace the synchronizers.

3. The guide bearing is jammed. Remove the gearbox, replace the bearing.

4. The gear shift drive rods/bushings are jammed. Disassemble the gear shift drive mechanism, replace worn and defective components. During assembly, do not forget to thoroughly lubricate the installed parts.

There are transmission oil leaks

1. Too much oil has been poured into the gearbox. Check the oil level and make any necessary adjustments.

2. The patency of the breathers or ventilation pipes is impaired. Check, eliminate blockages, if necessary, add the required amount of transmission oil to the gearbox.

3. The sealing gasket of the manual transmission housing is damaged, or pores/cracks have formed in the casting of the latter. Replace the defective components. Fill the gearbox with the required amount of oil of the required grade.

Clutch

Note. The clutch can be driven by rods, cables or hydraulically. On models with mechanical or cable drives, the amount of free pedal travel must be adjusted from time to time (as the driven disk wears). On models with hydraulic drives, adjustment is carried out automatically (except for the height of the pedal position, which is not subject to adjustment).

The clutch slips when driving uphill or during acceleration

1. The clutch pedal free travel adjustment is out of adjustment. Check by adjusting the rod/drive cable until the pedal free travel is approximately 25 mm.

2. The clutch driven disc is worn/damaged. Remove the engine/gearbox, replace the clutch assembly.

3. The petals of the diaphragm spring of the clutch pressure plate have become loose. Remove the engine/gearbox, replace the clutch assembly.

4. The quality of mechanical treatment of the working surfaces of the pressure plate/flywheel is impaired. Check and replace defective components.

The clutch does not disengage completely (gear shifting is difficult)

1. The clutch release drive mechanism is faulty. Assess the condition of the drive elements (cables/rods/hydraulic tract components), replace the faulty parts. On models with a hydraulic clutch drive, "bleed" the fluid tract, completely removing air locks from it.

2. The clutch release lever or its rotary unit is damaged. Check the condition of the lever, replace it if necessary.

3. The clutch slave disk hub or its torsion springs are damaged. Disassemble the clutch, replace the faulty components.

4. The clutch guide bearing is jammed. Disassemble the clutch, replace the defective components.

5. The driven disk is faulty. Disassemble the clutch, evaluate the flatness of the driven disk, make sure that the thickness of the friction linings does not exceed the maximum permissible value. Replace the corresponding components.

Pressing the clutch pedal is accompanied by extraneous noises

1. The pedal stop or free travel adjustment is disturbed. Check and make appropriate adjustments.

2. The release bearing is worn or damaged. If the noise intensity decreases when the pedal is released, the bearing should be replaced.

3. Excessive axial play of the engine crankshaft. Check the condition of the crankshaft thrust bearings, replace defective components.

Excessive force is required to depress the clutch pedal

1. The pedal axle is jammed. Check, eliminate the causes of blocking, replace defective components, lubricate the axle bushings.

2. The clutch drive cable is incorrectly routed or worn out (models with a cable drive). Assess the condition of the drive cable; if you find any pins, abrasions, traces of corrosion or other damage, replace the cable, trying not to bend the new one excessively. Check the quality of the power unit grounding; when the bus is disconnected, grounding may begin via the clutch drive cable, which leads to its premature wear.

3. On models with mechanical clutch drive, check the correct routing of the rods, make sure there are no signs of jamming. Lubricate the axial and support points, replace defective components.

4. There is a lack of lubrication of the release bearing guide tube and the clutch release fork. Check, fill the relevant components with heat-resistant grease, achieving complete freedom of movement of the bearing on the tube.

5. On models with hydraulic clutch drive, check the level of the working fluid, inspect the surfaces of the master and slave clutch cylinders for signs of leaks. Replace defective components, "bleed" the hydraulic circuit. If there are no signs of fluid leaks, it can be assumed that there is internal damage to the master hydraulic clutch cylinder. Replace the cylinder, "bleed" the system.

Clutch engagement is accompanied by vibration

1. The flywheel working surface is not flat. Check it and, if necessary, have the flywheel reground or replace it.

2. The clutch slave disk is deformed or its damper hub is damaged. Remove the clutch, replace the defective components.

3. The clutch pressure plate is damaged or the petals of its diaphragm spring are weakened. Replace the pressure plate.

Differential and final drive

The differential makes a low frequency grinding noise

1. The lubricating fluid level has dropped, or the wrong type of oil has been poured into the differential. Check and replace the oil if necessary.

2. Differential bearings are worn or damaged. Replace the bearings, check the condition of the drive and driven gears, and replace them if necessary.

The differential operation is accompanied by a howling sound

1. The lubricating fluid level has dropped, or the wrong type of oil has been poured into the differential. Check and replace the oil if necessary.

2. The differential drive and/or driven gear is worn or damaged. Check and replace defective components.

Transfer case

After the trip, traces of lubricating fluid leakage through the seals or breather are detected

1. There is too much lubricating fluid in the transfer case. Check the fluid level and make adjustments if necessary.

2. The breather or its hose is clogged. Check and eliminate the cause of the ventilation channel blockage; if necessary, add the required amount of fluid of the required grade to the transfer case housing.

3. Worn or damaged seals. Replace defective components, check the lubricating fluid level, and make appropriate adjustments if necessary.

The operation of the transfer case is accompanied by intense background noise

1. The wrong type of lubricant is poured into the transfer case. Empty the case and fill it with the correct type of lubricant.

2. The lubricating fluid level has dropped. Check and make adjustments if necessary.

3. There is damage to the internal components of the transfer case. Remove the box, disassemble it, assess the condition of the internal components, replace the defective parts.

The transfer case jumps out of the selected position

1. Stop driving and make sure the gearbox is fully engaged.

2. There is wear, loose fastening, or drive rod adjustment is disturbed. Check the condition of the transfer case drive, make the necessary corrections/adjustments/replacements.

3. There is wear or damage to the internal components of the transfer case.

4. Remove the box, disassemble it, assess the condition of the internal components, replace defective parts.

Cardan shaft (rear-wheel drive and all-wheel drive models)

Note: The sections of the driveshaft are usually connected to each other by means of universal (cardan) joints, however, on some models, constant velocity joints or rubber flexible couplings may be installed instead of the latter.

Shifting from forward to reverse is accompanied by a dull metallic click in the central part of the car's underbody

The cardan shaft crosspiece is worn out. Remove the shaft, replace the defective components.

Acceleration of the car is accompanied by vibrations in the central part of the car

1. The cardan shaft crosspiece is worn out. Remove the shaft, replace the defective components.

2. The driveshaft is not installed correctly. Check the condition of the powertrain suspension supports, tighten the fasteners, replace defective components.

3. The balance of the cardan shaft is disturbed due to deformation or bending. Check and replace defective components.

4. The propeller shaft is out of balance. Remove the shaft assembly and have it balanced. Alternatively, replace the shaft.

Drive shafts/axle shafts

Front/rear wheel spinning while driving is accompanied by clicking sounds

1. Foreign objects are stuck in the tread pattern. Check, clean the tread, and if necessary, have the wheel repaired.

2. Constant velocity joints (CV joints) are worn/damaged, or their fastening on the drive shafts has become loose. Assess the condition of the CV joints and replace them if necessary.

Acceleration of the car is accompanied by noticeable vibration of the front/rear wheels

1. The wheel disk is deformed. Check it, if necessary, send the corresponding wheel for repair or replace the defective disk.

2. Wheel balance is disturbed. Balance the wheels.

3. Wheel bearings are worn out or their preload has weakened. Check, replace bearings if necessary, adjust preload.

4. Constant velocity joints (CV joints) are worn/damaged, or their fastening on the drive shafts has become loose. Assess the condition of the CV joints and replace them if necessary.

Diagnostics of brake system faults

Note: Before concluding that the brake system is faulty, check the condition and inflation pressure of the tires, the uniformity of the vehicle loading, and the front wheel alignment angles.

Pressing the brake pedal is accompanied by jerking or pulsating sounds

1. Wheel nuts are loose. Check and tighten the wheel nuts evenly to the required force.

2. The brake disc is deformed or unevenly worn. Check and, if necessary, resurface or replace the defective disc.

Attention! The turning of the disk should not lead to a decrease in its thickness below the permissible limit!

3. The brake caliper mounting bolts or its anchor bracket have become loose. Check, tighten the fasteners with the required force, assess the condition of the load-bearing components.

4. Wheel bearing preload is loose. Check, adjust accordingly, replace bearings if necessary.

When braking, a characteristic high-frequency squealing sound of the brakes occurs

1. Grooves have formed on the outer edge of the brake disc(s). Check and, if necessary, resurface or replace the defective disc.

Attention! The turning of the disk should not lead to a decrease in its thickness below the permissible limit!

2. The working surfaces of the friction linings of the brake shoes are dirty. Remove the shoes and thoroughly clean the linings.

3. The brake pads are excessively worn. Check and replace.

4. The working surface of the friction linings is polished to a shine. Check, replace the pads/shoes together with the brake discs/drums.

5. The brake pad/shoe fastening elements are damaged by corrosion. Check, replace defective components, lubricate the installed parts with heat-resistant grease before assembly.

When braking, a grinding noise occurs in the central part of the wheels

1. The brake pads are excessively worn. Check and replace.

2. Partially or completely jammed brake components, resulting in premature and uneven wear of brake pads/shoes and discs/drums. Check and replace defective components.

During braking, the vehicle loses directional stability (the car pulls to the right or left)

1. Air has entered the hydraulic circuit of the brake system. Carefully inspect all components of the system for signs of developing leaks. Bleed the corresponding part of the hydraulic circuit. Replace the brake fluid.

2. The flexible brake hoses are clogged. Check, replace defective components, flush the hydraulic circuit.

3. Partially or completely jammed brake components, resulting in premature and uneven wear of brake pads/shoes and discs/drums. Check and replace defective components.

4. The geometry of the front of the car is damaged, or the suspension components are excessively worn. Check, replace defective components, tighten the fasteners, adjust the front wheel alignment angles.

5. Drum brake adjusters are faulty. Check, eliminate causes of blocking, replace defective components, adjust brakes.

There is softness or excessive travel of the brake pedal

1. The level has dropped or the brake fluid is contaminated. Check. If the brake system has not been flushed for more than two years, clean the walls of the brake master cylinder reservoir, flush the brake system, fill it with fresh fluid and bleed it.

2. Flexible brake hoses are damaged. Check and replace defective components.

3. Drum brake adjusters are faulty. Check, eliminate causes of blocking, replace defective components, adjust brakes.

Braking efficiency is clearly understated, despite the increased resistance of the foot brake pedal when pressed

1. The brake booster is faulty. Check, evaluate the condition of the servo control valve, replace the defective components.

2. The working surfaces of the friction linings of the brake shoes are polished to a shine. Check, replace the shoes, if necessary, eliminate defects in the working surfaces of the brake discs/drums.

3. Partially or completely jammed brake components, resulting in premature and uneven wear of brake pads/shoes and discs/drums. Check and replace defective components.

The uniformity of distribution of braking force between the front and rear wheels of the vehicle is disrupted

1. The regulator valve is worn, damaged or jammed. Replace the valve.

2. The spring/rod of the control valve drive is jammed or disconnected. Check and replace defective components.

The foot brake pedal, pressed to the floor, does not return to its original position when released

1. The hydraulic fluid level has dropped. Carefully inspect the brake system components for signs of leaks, replace defective parts, add the required amount of fluid to the brake master cylinder reservoir, and bleed the brake system.

2. The brake master cylinder is faulty. Replace the cylinder, fill the system with fresh brake fluid, bleed the hydraulic circuit.

Brake fluid smells like burning

1. Brake components are partially or completely jammed. Check and replace defective components.

2. The flexible brake hoses are clogged. Check and replace the defective hoses, flush the hydraulic circuit, and bleed the system.

3. The parking brake release mechanism is faulty. Check the condition of the drive cables and actuator levers, replace defective components.

Tips for diagnosing problems related to the functioning of the braking system

The causes of pulsations and vibrations that occur during braking are usually identified during road tests of the vehicle.

If vibrations occur in the brake pedal when it is depressed and are not transmitted to the steering wheel, then most likely the cause of their appearance is uneven wear or deformation of the discs/drums of the rear wheel brake mechanisms. Recoil in the steering wheel indicates the need to check the condition of the front wheel brake discs first.

Pedal failures during braking may be due to air getting into the hydraulic tract of the system, or to boiling of the working fluid as a result of "sticking" of the brake mechanisms or incomplete release of the parking brake. It is also possible that the adjustment of the drum brake mechanisms of the rear wheels is not correct. To check, without starting the engine, pump the brake pedal several times and, holding it depressed, cock the parking brake, then release the pedal and immediately depress it back. If the pedal "fails" when depressed again, then the rear brake mechanisms need adjustment.

Note: Do not compensate for drum brake misalignment by adjusting the parking brake, as this will result in premature wear of the brake shoe linings.

Diagnosis of wheel, tire, steering and suspension faults

Wheels and wheel bearings

Loose front wheel mountings/wheel bearing preload

All-wheel drive and front-wheel drive models

1. Loose hub nuts/wheel nuts. Check and tighten fasteners.

2. Wheel bearings are worn or damaged. Check, replace if necessary, adjust bearing preload.

Rear wheel drive models

1. Wheel bearings are out of adjustment. Adjust preload, if slack does not disappear, replace bearings.

2. Wheel nuts have loosened. Check and tighten the fasteners.

3. Wheel bearings are worn or damaged. Check, replace if necessary, adjust bearing preload.

Loose rear wheel mounts/wheel bearing preload

All-wheel drive and rear-wheel drive models

1. Loose hub nuts/wheel nuts. Check and tighten fasteners.

2. Wheel bearings are worn or damaged. Check, replace if necessary, adjust bearing preload.

Front-wheel drive models

Tires

There is one-sided tread wear

1. Wheel alignment is out of alignment. Check and make any necessary adjustments.

2. Tires are not inflated correctly. Check and make appropriate adjustments.

3. Suspension components are worn or damaged. Check, replace defective parts, adjust wheel alignment angles.

There is uneven wear on the tread

1. The tires are not inflated correctly or the wheels are out of balance. Check and make any necessary adjustments.

2. Wheel alignment is out of adjustment. Check and make necessary adjustments.

3. Shock absorbers are faulty. Check the condition of the suspension struts, replace defective components. Adjust the wheel alignment angles.

4. Wheel alignment is out of alignment. Check and make any necessary adjustments.

5. Suspension components are worn or damaged. Check, replace defective parts, adjust wheel alignment angles.

Steering drive

There is excessive play in the steering wheel

1. The steering gear free play adjustment is out of adjustment. Check and make appropriate adjustments.

2. Steering components are worn or damaged. Check, replace defective parts, adjust the front wheel alignment angles.

3. The steering mechanism is faulty. Check, replace, adjust the front wheel alignment angles.

Steering wheel vibrates when driving at cruising speed

1. Front wheel rims/tires are deformed. Check, replace defective rims, balance wheels.

2. There is uneven wear on the front tires. Replace the tires, make sure they are inflated according to regulatory requirements.

3. There is a hidden defect in the front tires. Replace the tires, make sure they are inflated according to regulatory requirements.

4. The front wheel assemblies are out of balance. Balance the wheels. Make sure that the wheel mounting bolts/nuts are tightened to the required torque.

5. Wheel bearings are loose. Check, adjust preload, replace faulty bearings if necessary.

The steering wheel vibrates when braking

See above Section on Brake System Fault Diagnosis.

Excessive force is required to turn the steering wheel

1. The steering wheel free play adjustment is out of adjustment. Check and make appropriate adjustments.

2. The steering gear is faulty. Replace the rack and pinion assembly, adjust the front wheel alignment angles.

3. Suspension components are worn or damaged. Check, replace defective parts, adjust front wheel alignment angles.

Suspension

The vehicle's directional stability is impaired

1. Tires are unevenly inflated. Check and make appropriate adjustments.

2. There is uneven wear of the treads. Check and replace the tires.

3. The front axle of the vehicle is equipped with wheels of different sizes, or the weight balance of the tires is disturbed. Check and make the necessary replacements.

4. Front wheel alignment is out of adjustment. Check and make appropriate adjustments.

5. Brakes are "stuck". Check the condition of the brake mechanisms, replace defective components, adjust the front wheel alignment angles.

The car sways excessively when driving on uneven road surfaces

1. Shock absorbers or other strut assembly components are worn or seized. Check and make necessary corrections/replacements.

Note: Shock absorbers are usually replaced in pairs.

The car rolls excessively when turning corners

1. Shock absorbers or other strut assembly components are worn or seized. Check and make necessary corrections/replacements.

Note: Shock absorbers are usually replaced in pairs.

2. Worn or damaged stabilizer bar strut/clamp components. Check and replace defective parts.

The car has an excessively harsh ride

1. The shock absorbers are jammed. Check the condition of the suspension struts, replace the defective components.

2. Tires are overinflated. Check and release excess pressure.

The car is too low or leans to one side

1. Damaged or sagging coil springs. Check and replace springs in pairs if necessary.

2. The shock absorbers are jammed. Check the condition of the suspension struts, replace defective components.

Extraneous noises and vibrations

The movement of the car is accompanied by clicking sounds

1. Check whether there is a relationship between the intensity of the sounds and the speed of the vehicle, whether the clicks disappear when coasting. If the frequency of the clicks changes proportionally to the speed and does not depend on the position of the gas pedal/steering wheel, check whether any foreign object is stuck in the tread pattern of any of the tires. If necessary, take the wheel to a tire shop.

2. If a relationship is found between the sound intensity and the vehicle speed/throttle/steering wheel position, check the condition of the CV joint, universal joint/flexible coupling of the propeller shaft.

Knocking and clicking noises when driving on uneven road surfaces

1. Suspension components are loose or damaged. Check (pay special attention to the condition of rubber-metal bushings and ball joints), replace defective parts.

2. The suspension component mounting bolts have become loose. Check the tightness of the subframe fasteners and the bolts of the axle joints of the suspension components. Tighten the fasteners to the required torque.

3. Wheel bearings are loose. Adjust preload, replace bearings if necessary.

4. Door hinges are out of adjustment. Check the door closing tightness, make the appropriate adjustments if necessary, tighten the hinge fasteners.

The movement of the car is accompanied by a low-frequency rumble

1. Sounds of this kind are usually a sign of failure of the transmission line bearings, mainly wheel bearings. The reason for bearing failure may be their overheating caused by the brakes "sticking", as well as damage when hitting a curbstone or a sewer manhole. When making turns, the intensity of the noise may vary, so when turning left, the load on the bearing of the right wheel increases and vice versa. Another sign of failure of the front wheel bearings is the appearance of vibrations in the steering wheel when turning. Damaged wheel bearings are subject to replacement.

2. Excessively worn/damaged tires or out of balance. Internal tire defects sometimes cause symptoms similar to those of damaged suspension components. Replace with a known good set of wheels.

When driving on uneven road surfaces, a characteristic metallic squeak occurs

1. The ball joints are worn out, or there is a loss of lubrication in them as a result of damage to the rubber protective covers. Check the condition of the ball joints, if any slack is detected, replace them. Do not forget to adjust the wheel alignment angles.

2. The rubber-metal bushings of the suspension component supports are damaged. Check, replace defective components, adjust the wheel alignment angles.

3. The rubber bushings of the stabilizer bar/torque rod mounts are twisted along the rod. Check the condition of the bushings and replace them if necessary. Lightly lubricate the seating surfaces of the bushings when installing.

The car's movement is accompanied by vibration

1. Vibrations are caused by uneven road surfaces.

2. Tires are worn/damaged, or wheel balance is out of order. Balance the wheels. Replace if necessary.

3. The joints (CV joint, universal joint or flexible coupling) of the propeller shaft are damaged. Check and replace defective components.

4. The drive shaft is bent or its fastening is loose. Check, tighten the fastening, replace if necessary.

Diagnostics of on-board electrical equipment failures

Headlights

One or both headlights are not functioning properly in low or high beam mode

1. The quality of the contact connection on the connector is damaged. Check the quality of the grounding of the headlight unit and the serviceability of the power supply to it from the battery. If the power supply is correct and the grounding is in order, replace the faulty lamp. If the power supply/grounding is damaged, check the condition of the wiring of the corresponding circuit (see the electrical connection diagrams).

2. The control switch is faulty. Replace it.

The brightness of one or both headlights is greatly reduced

1. The quality of the contact connection on the connector is damaged. Check the quality of the grounding of the headlight unit and the serviceability of the power supply to it from the battery. If the supply voltage on the connector is significantly low, check the condition of the components and connecting wiring of the corresponding circuit.

2. The base of the corresponding lamp or its socket is heavily oxidized. Carefully clean the contact surfaces, if necessary, replace the failed component.

Running lights and side lights

Running lights and side lights do not function

1. The quality of the contact connection on the connector is damaged. Check the quality of the grounding of the corresponding lighting device and the serviceability of the power supply to it from the battery. If the power is supplied correctly and the grounding is in order, check the condition of the socket, if necessary, replace the faulty lamp. If the power supply/grounding is damaged, check the condition of the wiring of the corresponding circuit.

2. The control switch is faulty. Replace it.

There are intermittent failures of running lights and side lights

1. The filament of the corresponding lamp is damaged. Check and replace the defective lamp.

2. The base of the corresponding lamp or its socket is heavily oxidized. Carefully clean the contact surfaces, if necessary, replace the failed component.

3. The electrical wiring or its contact terminals are damaged. Check and make appropriate corrections.

4. The control switch is faulty. Replace it.

The brightness of one of the lighting devices is greatly reduced

1. The quality of the contact connection on the connector is damaged. Check the quality of the grounding of the corresponding lighting device and the serviceability of the power supply to it from the battery. If the supply voltage on the connector is significantly low, check the condition of the elements and connecting wiring of the corresponding circuit (see the electrical connection diagrams).

2. The base of the corresponding lamp or its socket is heavily oxidized. Carefully clean the contact surfaces, if necessary, replace the failed component.

3. The control switch is faulty. Replace it.

Interior lighting fixtures

Interior lighting does not function

1. The control switch is set to the wrong position. Find the switch and set it to the correct position.

2. The quality of the contact connection on the lamp connector is damaged. Check the quality of the grounding and the serviceability of the power supply from the battery. If there is no power, check the condition of the corresponding fuse, replace it if necessary. Check the condition of the elements and connecting electrical wiring of the corresponding circuit (see electrical connection diagrams). If there is no grounding, check the condition of the contacts of the door sensors-switches, remove traces of corrosion, replace defective components if necessary.

There is an intermittent failure of the interior lighting

1. The filament of the corresponding lamp is damaged. Check and replace the defective lamp.

2. The base of the corresponding lamp or its socket is heavily oxidized. Carefully clean the contact surfaces, if necessary, replace the failed component.

3. The contact terminals of the external connector of the lamp are oxidized or damaged. Check, clean or replace the relevant components.

4. The door sensor switches are not functioning properly. Check and replace the faulty components.

The brightness of the interior lighting is greatly reduced

1. The quality of the contact connection on the connector is damaged. Check the quality of the grounding of the lamp and the serviceability of the power supply to it from the battery. If the supply voltage on the connector is significantly low, check the condition of the elements and connecting wiring of the corresponding circuit (see the electrical connection diagrams).

2. The base of the corresponding lamp or its socket is heavily oxidized. Carefully clean the contact surfaces, if necessary, replace the failed component.

3. One of the control switches/sensors is faulty. Replace it.

Brake lights

There is a failure of one of the brake lights

The voltage supply to the corresponding brake light bulb is faulty. Check if the power supply is correct, assess the grounding quality, and replace the bulb if necessary. If signs of a break in the power supply or ground circuit are detected, check the condition of the components and connecting wiring of the corresponding circuit (see electrical connection diagrams).

There is a failure of both brake lights

The brake light switch sensor adjustment is out of order. Check and make the appropriate adjustment. If the power supply to the brake lights remains interrupted despite the correct operation of the switch sensor, check the condition of the components and the connecting wiring of the corresponding circuit (see the electrical connection diagrams), make the necessary corrections.

The brightness of one or both brake lights is greatly reduced

The quality of the contact connection on one of the contact connectors of the corresponding circuit is damaged. Check the quality of the grounding of the lamp assemblies and the serviceability of the power supply to them from the battery. If the supply voltage on the connector is significantly underestimated, check the condition of the elements and connecting wiring of the corresponding circuit (see the electrical connection diagrams). Sometimes it is necessary to remove the defective connector and clean its mounting surface.

Control lamps

The indicator lamp(s) remains on after the engine has been started

Charge indicator light

1. Generator or voltage regulator is faulty. Check and replace faulty components.

2. There is a short circuit in the wiring circuit of the corresponding lamp. Check and make the necessary corrections.

Control lamp "Check engine"

1. It is time for the next engine maintenance, or the engine settings have been violated. Perform maintenance, check the settings, assess the condition of the spark plugs and air filter, check the level and condition of the engine oil. Make the necessary adjustments and replacements.

2. There is an intermittent leaning of the air-fuel mixture as a result of approaching the end of the fuel supply in the tank. Refuel the car, reinstall the lamp.

3. The quality of the contact connections in the injection/engine control system circuit is impaired. Check the condition of the electrical wiring and contact connectors of the control module and information sensors.

4. There is a loss of vacuum in the intake manifold. Check the condition of the sealing gasket and vacuum hoses. Replace defective components.

5. There is increased consumption of engine oil as a result of severe wear of internal engine components. Perform restorative repairs of the power unit.

ABS warning light

1. The contact connections of the wheel sensors are oxidized, or foreign particles are stuck between the teeth of the signal rotors. Check and make the necessary corrections.

2. There are leaks in the master cylinder. Inspect the cylinder, replace the failed seals and gaskets.

3. The ABS control module, hydraulic pump or control valves are not functioning properly. Check the condition of the components, make the necessary corrections/replace defective parts.

4. There is a malfunction in the electrical circuit of the wheel sensors/ABS control module. Carefully inspect the wiring, eliminate any defects found.

Brake system warning light

1. The hydraulic fluid level in the brake master cylinder reservoir has dropped. Check the hydraulic circuit of the brake system for signs of leaks, eliminate any detected faults, and add the required amount of fluid of the required grade to the reservoir.

2. The friction linings of the brake pads/shoes are excessively worn. Check and replace any defective components.

Attention! Replacement of brake pads/shoes is always carried out as a set for both wheels of the corresponding axle!

3. There is a defect in the indicator lamp signal sensor circuit. Check, make necessary corrections, replace the defective components.

Oil pressure warning light

Warning! Operating a vehicle with low oil pressure can result in serious internal engine damage, which will require costly repairs.

Note: One of the signs of an unacceptable decrease in oil pressure is an increase in detonation during engine operation.

4. When this warning light comes on, stop the engine immediately and check the engine oil level and the condition of the oil filter. If necessary, add the appropriate amount of oil from the canister, which should be kept in the car and renewed at each oil change.

5. The wiring of the oil pressure indicator lamp switch sensor is damaged. With the ignition on (do not start the engine), disconnect the wiring from the switch sensor - the indicator lamp should not light, otherwise check the wiring for signs of a short circuit to ground. Make sure the insulation is intact along the entire length of the wires, replace defective circuit elements.

6. The oil intake mesh filter is clogged. Remove the oil pan and clean the filter.

7. The oil pressure indicator lamp sensor-switch is not functioning properly. To check, install a new one

8. The full-flow oil filter is clogged or there are oil leaks. Replace the filter.

Parking brake engagement indicator light

1. The parking brake lever is not released. Remember to release the parking brake before starting to move.

2. The installation position of the control lamp switch sensor is disturbed, or there is a short circuit in its wiring circuit. Check and eliminate the detected faults.

3. The indicator lamp switch sensor is faulty. Check and replace.

The indicator lamp(s) starts flashing while driving

Charge indicator light

Control lamp "Check engine"

1. It is time for the next engine maintenance, or the engine settings have been violated. Perform maintenance, check the settings, assess the condition of the spark plugs and air filter, check the level and condition of the engine oil. Make the necessary adjustments and replacements.

2. There is an intermittent leaning of the air-fuel mixture as a result of approaching the end of the fuel supply in the tank. Refuel the car, reinstall the lamp.

3. The quality of the contact connections in the injection/engine control system circuit is impaired. Check the condition of the electrical wiring and contact connectors of the control module and information sensors.

4. There is a loss of vacuum in the intake manifold. Check the condition of the sealing gasket and vacuum hoses. Replace defective components.

5. The wiring of the control lamp circuit is damaged. Check the wiring for short circuits, eliminate any detected faults.

ABS warning light

Brake system warning light

Attention! Replacement of brake pads/shoes is always carried out as a set for both wheels of the corresponding axle!

3. There is a defect in the indicator lamp signal sensor circuit. Check, make necessary corrections, replace the defective components.

Oil pressure warning light

Warning! Operating a vehicle with low oil pressure can result in serious internal engine damage, which will require costly repairs.

Note: One of the signs of an unacceptable decrease in oil pressure is an increase in detonation during engine operation.

1. When this warning light comes on, stop the engine immediately and check the engine oil level and the condition of the oil filter. If necessary, add the appropriate amount of oil from the canister that should be kept in the car and renewed at each oil change.

2. The wiring of the oil pressure indicator lamp switch sensor is damaged. With the ignition on (do not start the engine), disconnect the wiring from the switch sensor - the indicator lamp should not light, otherwise check the wiring for signs of a short circuit to ground. Make sure the insulation is intact along the entire length of the wires, replace defective circuit elements.

3. The oil intake mesh filter is clogged. Remove the oil pan and clean the filter.

4. The oil pressure indicator lamp switch sensor is not functioning properly. To check, install a known good sensor.

Parking brake engagement indicator light

The indicator lamp(s) do not light when the ignition is turned on without starting the engine

1. The lamp is faulty - check by substituting a known good one.

2. There is a break in the circuit. Check the condition of the corresponding electrical wiring.

3. The corresponding sensor-switch is faulty, or there is a defect in its wiring circuit. Check, eliminate the detected faults, replace the defective components.

Direction indicators hazard warning lights

The signal lights come on but operate continuously

The breaker is faulty. Replace the faulty unit.

There is a two-way failure of the signal lights

1. The fuse has blown. Check and replace.

2. The circuit breaker is out of order - check by substituting a known good unit.

3. There is a fault in the electrical wiring circuit. Check and correct any faults found.

There is a one-sided failure of the signal lights

1. The lamps are burnt out. Check and replace the defective lamps.

2. The quality of grounding of the assemblies of the corresponding lights is broken. Check and eliminate the break.

Only one of the signal lights does not turn on

1. The lamp has burned out. Check and replace it.

2. The contact surfaces of the base/cartridge are oxidized. Check and clean the terminals.

3. The quality of the grounding of the socket of the corresponding lamp is broken. Check and eliminate the break.

The frequency of flashing signal lights is greatly reduced

The lamps installed are too powerful. Replace the lamps.

The frequency of flashing signal lights has increased significantly

1. The lamps installed are not powerful enough. Replace the lamps.

2. The wrong type of breaker is installed. Replace the breaker.

The hazard warning light is not functioning properly

1. The corresponding external signal lights are faulty. Check and replace the indicator lamp if necessary.

2. The hazard warning switch is faulty. Check and replace if necessary.

One of the direction indicator lamps is not functioning properly

1. The lamp has burned out. Check and replace it.

2. The breaker is faulty - check by substituting a known good unit, replace if necessary.

Horn

There is no sound signal

1. The corresponding fuse has blown. Check and replace if necessary.

2. The power supply to the horn is faulty, or there is a break in the ground circuit. Check. If the power supply is correct, replace the horn. If a fault is detected, check the condition of the corresponding electrical wiring.

The tone of the horn has changed

1. On models with one horn, replace the latter.

2. On models with a 2-horn horn, check the correct operation of the second horn. Disconnect the wiring from the horns one by one and check the correct operation of each of them separately. Replace the failed component.

3. Check the correct installation of the horn(s) - the horns should be installed with the bell facing down. Make sure that no foreign objects have gotten inside the horn.

Windscreen wipers

Windscreen wipers do not work

1. The fuse has blown. Check and replace.

2. The control switch is faulty. Check, fix any problems found, replace the switch if necessary.

3. The quality of the contact connections in the windshield wiper drive circuit is damaged. Check, clean the terminals, replace the faulty elements.

4. The quality of the grounding of the control switch or the drive electric motor is broken. Check and eliminate any detected breaks.

The drive electric motor overheats, turning on the windshield wipers causes the fuse to blow

1. There is internal damage to the electric motor. Replace it.

2. The wiper arm drive rods are jammed or deformed. Check, make necessary corrections, replace the faulty components.

One or both windshield wiper arms are not functioning properly, although the drive motor is working properly

1. The fastener of the corresponding drive rod is loose. Check and tighten the fastener.

2. The lever mount on the drive axle has become loose. Tighten the nut, if necessary, replace the corresponding lever/drive axle assembly.

When switched off, the brushes do not return to the parking position

1. As a result of a control switch malfunction, the order of power supply disconnection from the drive electric motor is disrupted. Check and eliminate the detected malfunctions.

2. There is a fault in the drive motor parking circuit. Replace the electric motor. Before installing the levers, start the system to determine the correct parking position of the windshield wipers. After completing the installation, turn on the windshield wipers at maximum speed and make sure that the brushes do not hit the window opening trim in their extreme positions.

Diagnostics of instrument cluster failures

Cable operated speedometer

The speedometer is completely out of order

1. The drive cable is not connected correctly to the meter assembly or drive gear. Check and make any necessary corrections.

2. The drive cable is broken or the ends that secure it to the meter/drive pinion assembly are rounded. Check and replace the cable if necessary.

3. The speedometer drive gear is worn. Check and replace if necessary.

4. The meter is faulty - check by substituting a known good assembly. Replace if necessary.

There are fluctuations in the meter needle when moving at a constant speed

1. The cable is not routed correctly, there are kinks or twists. Check, make the necessary corrections, and if signs of damage to the sheath are detected, replace the cable.

2. The cable assembly needs lubrication. Remove the cable, inspect it for damage (replace if necessary), lubricate and reinstall.

There are intermittent disturbances in the speedometer operation

1. The cable is not fully connected and is not securely fixed in the clamps. Check and make the necessary corrections.

2. The cable ends are worn (rounded). Check and replace the cable assembly if necessary.

Electric speedometer

The speedometer is completely out of order

1. The inductive starter of the speed sensor (VSS) is faulty. Replace the sensor.

2. The wiring in the circuit section between the VSS and the speedometer is damaged. Inspect the wiring, assess the quality of the contact connections, eliminate the identified faults, replace the defective components.

3. The meter is damaged - check by substituting a known good assembly. Replace if necessary.

There are intermittent disturbances in the speedometer operation

1. The quality of the contact connections in the circuit section between the VSS and the speedometer is damaged. Check, make the necessary corrections, replace the defective components.

2. The inductive starter of the speed sensor (VSS) is faulty. Replace the sensor.

Fuel consumption, engine temperature and oil pressure gauges

The functioning of the meter is completely disrupted

1. The corresponding fuse has blown. Check and replace.

2. There is a break in the wiring circuit of the corresponding meter. Check and eliminate the detected faults.

3. The corresponding sensor is faulty. Check and replace.

4. The installation of the measuring device or its sensor is incorrect. Check and make appropriate corrections.

The stability of the meter readings is disrupted

1. The quality of the contact connections of the corresponding electrical circuit is damaged. Check and eliminate the detected faults.

2. The meter is faulty. Replace it.

The meter continuously records the maximum reading

1. There is a short circuit to ground in the wiring circuit of the corresponding meter.

2. The meter is faulty. Replace it.

3. The meter's grounding is faulty. Check and fix the break.

4. The installation of the measuring device or its sensor is incorrect. Check and make appropriate corrections.

Diagnostics of malfunctions of heating and air conditioning systems

Heater

The heater fan is completely out of order

1. The corresponding fuse has blown. Check and replace.

2. There is a break in the electrical wiring. Check. Eliminate the detected faults in the circuit.

3. There is an open circuit in the fan control switch/resistive assembly circuit. Check and correct any faults found.

4. The fan drive electric motor is faulty. Check and replace if necessary.

The supply of heated air to the cabin is disrupted

1. The fluid level in the engine cooling system is insufficient. Check, make the appropriate adjustments, remove air locks from the cooling system tract.

2. The engine does not warm up to normal operating temperature. Check the thermostat for proper operation. Check and replace the thermostat if necessary.

3. The inlet valve of the heat exchanger (radiator) of the heater is faulty. Check the correct operation of the cable/vacuum drive of the valve. Move the temperature mode selection switch to the extreme positions several times, checking the correct operation of the valve. Warm up the engine to normal operating temperature and, having selected the maximum temperature mode of the heater, feel the hoses at the inlet and outlet of the valve assembly. If the hoses have different temperatures, replace the valve.

When the heater is turned on, the windshield fogs up

1. The fastening clamp has become loose and a coolant leak has developed from the hose located near the engine compartment bulkhead or under the vehicle's instrument panel. Check and eliminate any identified faults.

2. There are leaks of coolant from the heater heat exchanger. Carefully inspect the mats in the driver's and front passenger's footwells for leaks.

Note: The coolant has a characteristic sweetish smell. If necessary, make the appropriate repairs or replace the failed heat exchanger. On some models, to provide access to the heat exchanger (radiator) of the heater, it is necessary to remove the instrument panel.

Air conditioner

Air does not flow through the air conditioning vents

1. The corresponding fuse has blown. Check and replace if necessary.

2. The air conditioning system needs charging.

Attention! Emptying, charging and checking the refrigeration system must be carried out in a specialized workshop!

3. The low-pressure pressure switch of the air conditioning system is faulty. Replace the switch.

4. The resistive assembly of the air conditioner fan is faulty. Check and replace the assembly if necessary.

5. There is damage to the wiring of the air conditioning system circuit, or the corresponding relay has failed. Check, eliminate the detected faults, replace the relay if necessary.

Heated air enters through the air conditioning system deflectors

1. The air conditioning system needs charging.

Attention! Emptying, charging and checking the refrigeration system must be carried out in a specialized workshop!

2. The compressor clutch is not functioning properly. Check the condition of the clutch and its circuit wiring. Eliminate any faults found, replace defective components.

When using K/V, moisture streaks form on the floor in the cabin

1. The patency of the air conditioning system evaporator drain pipe is impaired. Clean the pipe where it exits the car interior.

2. The evaporator drain hose is clogged. Clean the hose where it exits the car.