A fundamental step in identifying the causes of any failure is the choice of a starting point for the search. Often the reason is on the surface, but in some cases you have to work hard, conducting a little investigation. A car enthusiast who has made half a dozen random checks, replacements and corrections has a good chance of discovering the cause of the failure (or its symptom), However, this approach cannot be called reasonable in any way, due to its laboriousness and aimlessness of time and money. Much more effective is a calm, logical approach to finding a failed node or component. It is imperative to take into account all the symptoms and warning signs that preceded the breakdown, sometimes minor, such as loss of engine power, changes in meter readings, the occurrence of unusual sounds and smells, etc. Keep in mind that failure of components such as fuses or spark plugs may only be a symptom of a deeper problem.
Below in this subsection, a fairly simple scheme for diagnosing the most common failures is given. The causes of violations and their symptoms are grouped according to their relationship to the functioning of a particular unit or system: "Engine", "Cooling system" etc.
Regardless of the nature of the failure, the investigation of its cause is always based on the same basic principles:
- Make sure you identify the symptoms of rejection correctly. The foregoing means confidence in determining the boundaries of the search area, which is especially important when diagnosing a failure to another motorist who cannot adequately state the symptoms of an existing violation.
- Try not to overlook obvious violations. For example, if the engine won't start, feel free to check for fuel in the gas tank (at the same time, the statements of the owner of the faulty car should not be taken for granted). In the event of a failure of electrical equipment, first of all, you should check the condition and reliability of fastening of the terminal connections of the electrical wiring, only after that it makes sense to get diagnostic tools.
- Try to address the cause of the failure, not its symptom. Replacing a dead battery with a new one will help start the engine, but the existing cause of the discharge of the old battery will remain uncorrected, which will lead to a quick failure of the new one. Also, replacing spark plugs thrown with oil will allow you to restore the correct functioning of the engine for some time, but the failure will certainly repeat soon (if the reason lay not simply in the use of candles of the wrong type).
- Don't take any statements for granted. remember, that "new" a component can also be defective, especially if it has been in the trunk for a long time - you should not exclude a component from the list of checks just because it is new or recently installed. In case of neglecting the implementation of this recommendation, one should not be surprised when the reason for the failure, finally revealed, turns out to be lying on the surface from the very beginning.
Diagnosing engine starting problems
Gasoline engines
Engine cranks but won't start
1. Fuel tank is empty. Check and refuel if necessary.
2. Low battery (engine cranks too slowly). Check and, if necessary, recharge or replace the battery.
3. The battery terminals are oxidized, or the wire ends are loosened on them. Clean contact surfaces, replace worn or damaged components.
4. Fuel is not being supplied to the injection injectors. Check the condition of the fuel pump, related wiring, fuse and relay.
5. There is excessive wear or mechanical damage to the internal components of the saga. Measure the compression pressure in the cylinders, evaluate the condition of the timing drive components, valve guides and valve stems, check the valve clearance setting.
6. Water has entered the fuel. In cold weather, the crystallization of moisture in the fuel can lead to blockage of the fuel lines. The use of special additives can make the engine easier to start, but then it is recommended to empty 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 setting of the interelectrode gaps. If the situation is aggravated by increasing humidity, check for a short circuit between the spark plugs and the ignition coils.
8. Serviceability of functioning of a control system of the engine is broken. Check the status of the relevant sensors and system control module.
Engine won't crank when trying to start it
1. If, when the engine is cranked with a starter, the brightness of the instrument panel illumination lamps is greatly reduced, evaluate the condition and charge level of the battery, check the generator for proper operation. Evaluate the quality of the contact connections of the corresponding electrical wiring. Measure the generator output voltage. Make appropriate corrections, replace worn-out components.
2. Faulty sensor-switch opening the starter circuit (RKPP) / sensor-switch of permission to start (AT). Make sure you fully depress the clutch pedal (RKPP), - on some models, the starter circuit opening switch must be adjusted. Follow the unambiguous installation of the selector lever in position "R" or "N" (AT). Assess the condition of the electrical wiring of the circuit of the corresponding sensor-switch and its contact sockets. Make the necessary corrections, replace failed components.
3. The correct functioning of the starter is broken. Check the condition of the magnetic starter and the starter enable relay. Evaluate the quality of the contact connections of the corresponding electrical wiring. Check that the unit is properly grounded to chassis ground. If battery voltage is present at the relay, try a test run with the remote starter. Make the necessary corrections, replace failed components.
4. Stuck engine. If the car has not been used for a long time, the probability is quite high "sticking" piston rings to the cylinder mirrors as a result of the development of surface corrosion. Another possible reason for blocking the engine may be the formation of hydraulic plugs as a result of suction of moisture. Turn out the spark plugs and try to turn the engine with a wrench on the crankshaft pulley bolt, reasonably commensurate with the applied force. If jamming occurs, try to identify and eliminate its cause.
Engine starts but immediately stalls
1. Faulty ignition switch. Assess the condition of the contact elements in the RUN position of the key. Try again to start, having previously turned off all on-board electrical consumers. Sometimes, in case of wear of the key, it turns out to be enough to turn it back and forth several times - replace the key as soon as possible.
2. The electrical wiring of the ignition system circuit is broken or otherwise damaged, or the fastening of the terminals of its contact connections is loose. Perform appropriate checks, make necessary corrections, replace defective components.
3. There are vacuum losses in the intake manifold. Assess the condition of the respective 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 power system is usually accompanied by a noticeable decrease in the vehicle's throttle response during acceleration. Check the patency of the fuel lines. The fuel pump cannot be adjusted and must be replaced if it fails.
5. Serviceability of functioning of systems of injection/management of the engine is broken. Assess the condition of the wiring and contact connections of the relevant information sensors and the control module.
6 Passability of a path of system of release of the fulfilled gases is broken. Check and fix the identified problems.
Entering the starter into gear is difficult, or accompanied by extraneous noise
1. Broken, worn, or jammed starter drive gear teeth. Check and make any necessary corrections.
2. Worn or damaged flywheel ring gear. Remove the inspection window cover and visually inspect the flywheel.
When cranking the engine, the starter makes extraneous noises
1. Damaged starter drive gear or flywheel ring gear. Check and make any necessary corrections.
2. The starter fasteners are loose, or there is mechanical damage to the housing. 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 current-voltage characteristic of the starter electric motor. Recharge the battery or replace the starter.
2. The pole terminals of the battery are oxidized, or the fastening of the wire lugs on them is loose. Check, make necessary corrections, clean terminals, replace defective components.
3. The serviceability of the functioning of the power supply system is broken. Estimate the pressure developed by the fuel pump, check the patency of the injection injectors. Replace failed components.
4. Primary engine settings are violated. Carry out the appropriate checks, evaluate the condition of the spark plugs and the correct setting of the electrode gaps. On models with manual valve clearance adjustment, check accordingly and make any necessary adjustments if necessary.
5. Faulty coolant temperature sensor. Carry out an appropriate check, if necessary, replace the failed sensor.
6. Serviceability of functioning of systems of injection/management of the engine is broken. Assess the condition of the wiring and contact connections of the relevant information sensors and the control module. Make appropriate corrections or replace defective components.
Difficulty starting a hot engine
1. The filter element of the air cleaner is dirty, or its patency is otherwise impaired. Replace the filter, check the patency of the air intake tract.
2. Faulty motor grounding. Evaluate the quality of the relevant contact connections, make the necessary corrections, replace defective components.
3. Engine needs maintenance. Check that the initial settings are set correctly. Evaluate the proper functioning of the lubrication, power and engine control systems.
Diesel engines
Engine cranks but won't start
1. 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 refuel with good quality fuel.
3. The compression pressure in the cylinders has dropped. Carry out an appropriate check, if necessary, recondition the unit.
4. The correct installation of the valve timing of the high-pressure fuel pump is violated. Check the correct adjustment of the pump, if necessary, make the appropriate adjustment.
5. Faulty injection pump. Check the condition of the pump, if necessary, replace it. Check that the new pump is properly adjusted.
6. Serviceability of functioning of atomizers is broken. Check and replace defective components.
Engine won't crank when trying to start it
1. If, when the engine is cranked with a starter, the brightness of the instrument panel illumination lamps is greatly reduced, evaluate the condition and charge level of the battery, check the generator for proper operation. Evaluate the quality of the contact connections of the corresponding electrical wiring. Measure the generator output voltage. Make appropriate corrections, replace worn-out components.
2. Faulty sensor-switch opening the starter circuit (RKPP) / sensor-switch of permission to start (AT). Make sure you fully depress the clutch pedal (RKPP), - on some models, the starter circuit opening switch must be adjusted. Follow the unambiguous installation of the selector lever in position "R" or "N" (AT). Assess the condition of the electrical wiring of the circuit of the corresponding sensor-switch and its contact sockets. Make the necessary corrections, replace failed components.
3. The correct functioning of the starter is broken. Check the condition of the magnetic starter and the starter enable relay. Evaluate the quality of the contact connections of the corresponding electrical wiring. Check that the unit is properly grounded to chassis ground. If battery voltage is present at the relay, try a test run with the remote starter. Make the necessary corrections, replace failed components.
4. Stuck engine. If the car has not been used for a long time, the probability is quite high "sticking" piston rings to the cylinder mirrors as a result of the development of surface corrosion. Another possible reason for blocking the engine may be the formation of hydraulic plugs as a result of suction of moisture. Remove the injectors and try to turn the engine with a wrench on the crankshaft pulley bolt, reasonably commensurate with the applied force. If jamming occurs, try to identify and eliminate its cause.
Engine starts but immediately stalls
1. The patency of the fuel return line or its control valve is broken. Carry out appropriate checks, eliminate the causes of line blockage, if necessary, replace defective components.
2. Glow plugs are switched off too early. Check and make any necessary corrections.
3. The adjustment of the injection pump is broken. Check the installation of the valve timing, make the necessary adjustments.
4. Vehicle filled with low-grade diesel fuel. Check, if necessary, empty the fuel tank and flush it and refuel with good quality fuel.
5. The compression pressure in the cylinders has dropped. Carry out an appropriate check, if necessary, recondition the unit.
6. There are air pockets in the fuel path. Check the fuel level in the fuel tank, refuel if necessary.
7. Faulty injection pump. Check the condition of the pump, if necessary, replace it. Check that the new pump is properly adjusted.
Entering the starter into gear is difficult, or accompanied by extraneous noise
1. Broken, worn, or jammed starter drive gear teeth. Check and make any necessary corrections.
2. Worn or damaged flywheel ring gear. Remove the inspection window cover and visually inspect the flywheel.
When cranking the engine, the starter makes extraneous noises
1. Damaged starter drive gear or flywheel ring gear. Check and make any necessary corrections.
2. The starter fasteners are loose, or there is mechanical damage to the housing. Check, tighten the fasteners, replace the faulty starter.
Diagnosis of problems arising during the operation of the engine
Gasoline engines
Idle speed stability is broken
1. Serviceability of functioning of system of ignition is broken. Check the condition of the system components and correct adjustments. Make necessary adjustments, replace defective components.
2. The patency of the injection injectors is broken. Check and replace defective components.
3. Decreased performance of the fuel pump. Check the patency of the fuel lines, if necessary, replace the pump.
4. Serviceability of functioning of a control system of the engine is broken. Check and make any necessary corrections.
Decreased engine power
1. Primary engine settings are violated. Carry out the appropriate checks, evaluate the condition of the spark plugs and the correct setting of the electrode gaps. On models with manual valve clearance adjustment, check accordingly and make any necessary adjustments if necessary.
2. The filter element of the air cleaner is dirty, or its patency is otherwise impaired. Replace the filter, check the patency of the air intake tract.
3. Serviceability of functioning of systems of injection/management of the engine is broken. Assess the condition of the wiring and contact connections of the relevant information sensors and the control module. Make appropriate corrections or replace defective components.
4. The pressure developed by the fuel pump has fallen. Check the pressure in the power system path, make the necessary remedial repairs, replace defective components.
5. The correct adjustment of the throttle actuator components is violated. Check the completeness of the throttle opening, evaluate the degree of wear of the bushings of the rotary drive units. Replace defective components.
6. Passability of a path of system of release of the fulfilled gases is broken. Inspect system components for deformations and other mechanical defects. Compare the temperature at the inlet and outlet of the catalytic converter and the muffler - if the temperature of the inlet flow is much higher than the temperature of the outlet, therefore, the permeability of the corresponding component is impaired.
7. Faulty or too loose knock sensor. Violation of the sensor tightening force can lead to ignition delay and, as a result, a decrease in the power developed by the engine. Assess the condition of the sensor, check its tightening force, replace if necessary.
8. There is an internal mechanical defect in the engine (reduction in compression pressure, wear of piston rings, valves, camshafts and timing components). It is necessary to carry out a refurbishment of the power unit.
9. Engine oil level too high. Check and make appropriate adjustments. Change the 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. "tacked on" brakes. Check and make any necessary corrections. Replace defective components.
13. Excessively worn or incorrectly inflated tires. Check and make appropriate adjustments if necessary. If necessary, replace the tires, make sure that their wear is not associated with a violation of the wheel alignment / geometry of the suspension or bodywork - such violations can cause an increase in the coefficient of friction and, as a result, a decrease in the efficiency of the engine output.
14. Low-octane gasoline was used to refuel the car. Fill the fuel tank with quality fuel.
Excessive fuel consumption
1. The air cleaner element is dirty or otherwise obstructed. Replace air filter.
2. Primary settings of the engine / ignition and power systems are violated. Assess the condition of the ignition system components, replace worn items. Check the correct setting of the ignition timing and the adjustment of the quality of the air-fuel mixture.
3. Wrong-sized wheels, improperly inflated tires, or excessive tire tread wear. Installing oversized wheels leads to an increase in resistance to their rotation. A vehicle with too small wheels requires higher engine speeds to maintain normal speed. Excessive tread wear may be due to incorrect tire inflation, wheel alignment or suspension geometry. All of these phenomena lead to an increase in fuel consumption due to an increase in the load on the engine under the same operating conditions of the vehicle.
4. "tacked on" brakes. Check and make any necessary corrections. Replace defective components.
The engine continues to run after the ignition is turned off (diesel effect)
1. Excessively high idle speed is set. Check and make appropriate adjustments.
2. Serviceability of functioning of the valve of stabilization of turns of idling is broken. Check, replace defective valve.
3. The setting of the ignition timing is violated. Check the condition of the relevant information sensors and other components of the ignition system. Replace defective items.
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 serviceability of the functioning of the power supply / engine control system is broken. Check the condition of the relevant information sensors and control modules. Replace defective components.
During acceleration or when the load on the engine is increased, there are knocks caused by too early ignition or detonation
1. The car was fueled with low octane gasoline. Fill the fuel tank with quality fuel.
2. The setting of the ignition timing is violated. Check the condition of the relevant information sensors and other components of the ignition / engine management system. Replace defective items.
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 installed. Replace the spark plugs, make sure the electrode gaps are set correctly.
Note. When operating the vehicle in high-speed mode, it is better to install more "cold" candles.
5. The serviceability of the functioning of the power supply / engine control system is broken. Check the condition of the relevant information sensors and control modules. Replace defective components.
6. Passability of a path of system of release of the fulfilled gases is broken. Inspect system components for deformations and other mechanical defects. Compare the temperature at the inlet and outlet of the catalytic converter and the muffler - if the temperature of the inlet flow is much higher than the temperature of the outlet, therefore, the permeability of the corresponding component is impaired.
7. Faulty or too loose knock sensor. Violation of the sensor tightening force can lead to ignition delay and, as a result, a decrease in the power developed by the engine. Assess the condition of the sensor, check its tightening force, replace if necessary.
An increase in engine speed is not accompanied by an increase in vehicle speed
1. "slips" clutch (RKPP). See the subsection on clutch troubleshooting below.
2. "slips" transmission (AT). Check the ATF level and condition in the gearbox. Make appropriate adjustments if necessary. If the ATF emits a distinctly audible burning smell, then the cause of the problem is the slippage of the internal components of the transmission. Performing an ATF and filter change may provide a temporary fix. At the first opportunity, you should make a refurbishment or replacement of the AT.
Diesel engines
Idle speed stability is broken
1. The adjustment of the injection pump is broken. Check and make any necessary adjustments.
2. There are air pockets in the fuel path. Check the fuel level in the fuel tank, refuel if necessary. Check fuel lines for leaks, make necessary repairs.
3. The patency of the fuel filter, or the fuel supply and return lines is broken. Check the condition of the fuel path, replace defective components.
4. Vehicle filled with low-grade diesel fuel. Check, if necessary, empty the fuel tank and flush it and refuel with good quality fuel.
Decreased engine power
1. The air cleaner filter element/inlet air path lines are blocked. Check the status of the components. If necessary, replace the air filter/defective lines.
2. The adjustment of the injection pump is broken. Check and make any necessary adjustments.
3. Passability of system of release of the fulfilled gases is broken. Check up a condition of components of an exhaust path. Eliminate the identified violations.
4. The patency of the fuel filter is broken. Check and replace if necessary.
5. The patency of the ventilation system of the fuel filler cap is broken. The presence of a blockage is indicated by a characteristic hiss that occurs when the lid is opened. Replace cap if necessary.
6. The patency of the fuel path components is impaired. Check, make necessary corrections, replace defective elements.
7. The compression pressure in the cylinders has dropped. Carry out the appropriate check. Check for external leaks (e.g. via glow plugs and fuel injection nozzles). If necessary, the unit should be repaired.
Diagnosis of the causes of noise, odors and vibrations that occur during engine operation
During acceleration or when the load on the engine is increased, there are knocks caused by too early ignition or detonation
1. The car was fueled with low octane gasoline. Fill the fuel tank with quality fuel.
2. The setting of the ignition timing is violated. Check the condition of the relevant information sensors and other components of the ignition / engine management system. Replace defective items.
3. Faulty or too loose knock sensor. Violation of the sensor tightening force can lead to ignition delay and, as a result, a decrease in the power developed by the engine. Assess the condition of the sensor, check its tightening force, replace if necessary.
4. Non-standard spark plugs installed. Replace the spark plugs, make sure the electrode gaps are set correctly.
Note. When operating the vehicle in high-speed mode, it is better to install more "cold" candles.
5. There is excessive carbon formation in the combustion chambers. Use special fuel additives, or disassemble and decarbonize the cylinder head.
6. The serviceability of the functioning of the power supply / engine control system is broken. Check the condition of the relevant information sensors and control modules. Replace defective components.
7. Passability of a path of system of release of the fulfilled gases is broken. Inspect system components for deformations and other mechanical defects. Compare the temperature at the inlet and outlet of the catalytic converter and the muffler - if the temperature of the inlet flow is much higher than the temperature of the outlet, therefore, the permeability of the corresponding component is impaired.
High-frequency squealing or whistling occurs when the engine is running
1. Accessory drive belts worn or loose. Check, make necessary adjustments, replace worn belts.
2. Worn or seized auxiliary belt tensioner bearings. Check the tensioners, if necessary, replace the components.
3. Faulty water pump. The pump may not leak, which does not exclude the possibility of worn bearings or loose/seized rotors. Replace pump.
When the engine is running, there is a metallic rattle
1. The water pump is faulty, or its mounting bolts are loose. Check fastener torque, replace defective pump.
2. Worn or seized auxiliary belt tensioner bearings. Check the tensioners, if necessary, replace the components.
During engine operation, various kinds of knocks occur
1. Serviceability of functioning of hydraulic correctors of valve backlashes in pushers is broken (on corresponding models). Check the level and condition of the engine oil. Change the oil and oil filter if necessary. Check if the pushers have collapsed. Replace defective components. In addition, the proper functioning of the hydraulic tappets depends on the pressure of the engine oil - check the oil filter for patency, the condition of the oil pump and its pressure reducing valve.
2. On models with manual adjustment of valve clearances, check the installation of the latter and assess the degree of wear of the timing components. If necessary, make the appropriate adjustment, replace the failed parts.
3. Worn or incorrectly adjusted timing belt/chain. Check, make necessary adjustments, replace defective drive components.
4. Deformed or otherwise damaged intake or exhaust valve stems. Remove the cylinder head, check the condition of the valve assembly components, replace defective parts.
When the engine is running, there is a strong thud
1. Loose fastening of the crankshaft pulley or flywheel. Check, replace the fixing bolts and tighten them to the required torque.
2. As a result of hydraulic blocking, deformation of the connecting rod occurred (ov). The necessary reconditioning of the power unit should be carried out.
3. Excessively worn or damaged connecting rod bearings - this kind of situation most often occurs as a result of a decrease in oil pressure. Carry out the appropriate reconditioning of the engine.
When the engine is running, there is a distinct smell of gasoline in the passenger compartment and near the car
1. Check the fuel level, - overfilling the tank can lead to minor fuel leaks through the neck. The smell should disappear already in the first 20÷25 km as a result of purge of the carbon adsorber.
2. The tightness of the fit of the fuel filler cap is broken. Check, tighten the cover, if necessary, replace it.
3. The hose clamps of the fuel supply or return lines of the fuel system path have loosened. Check the fastening of the clamps, if necessary, make appropriate replacements. It is also possible that the sealing glands of the active components of the power system will fail. Check and replace defective seals.
4. Evaluate the fuel economy. If the increase in flow is due to the failure of the functioning of any components, or to a malfunction in the ignition of the air-fuel mixture, contamination of the catalytic converter may occur. Usually, the driver is warned about the occurrence of such situations by the operation of the warning lamp "Check engine". Check the condition of the spark plugs, or analyze the composition of the exhaust gases. Replace faulty spark plugs and failed components of the power system.
When the engine is running, there is a smell of hydrogen sulfide near the car (rotten eggs)
1. As a result of supplying a lean mixture to the combustion chambers, the catalytic converter overheats, in which an irreversible chemical reaction occurs with the release of hydrogen sulfide. Check up serviceability of a condition of a sealing lining and vacuum lines of an inlet path, make necessary corrections.
2. As a result of a malfunction in the functioning of the generator or voltage regulator, the battery is constantly recharged, accompanied by boiling of the electrolyte. Carefully inspect the battery case for cracks, blisters, or 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 alternator/voltage regulator for proper operation, make necessary repairs or replace failed components.
There is a sweet smell when the engine is running near the car
1. There are external coolant leaks. Check the condition of the radiator cap, seals and gaskets of the components of the cooling path, evaluate the tightness of the hose clamps. Tighten fasteners, replace 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 fluid leaks on the mats under the instrument panel.
3. As a result of the development of internal leaks, coolant enters the combustion chambers, which is usually accompanied by the release of thick white smoke / steam in the exhaust. This kind 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 are whitish deposits on the inside of the engine oil filler cap, and kinked or swollen radiator hoses.
When the engine is idling, strong vibrations occur
1. The fastening of the suspension mounts of the power unit is loose, or their rubber pads 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 is loose. Check, tighten the fasteners, restore the original shape of the protective plates.
Vibration intensity increases during acceleration
1. Damaged or lost rubber suspensions of the supports of the elements of the exhaust system. Check and replace defective components.
2. The correct laying of sections of the exhaust system is violated. Evaluate the adequacy of the gasket, make sure that the components of the exhaust system do not come into contact with body elements and suspension elements.
Diagnostics of malfunctions of electric equipment of the engine
Battery drains while driving
1. The battery does not hold a charge. A decrease in the electrolyte level in the banks can occur as a result of overcharging the battery. Check the alternator/voltage regulator for proper operation, make necessary repairs, or replace failed components.
2. The quality of the electrical contact on the terminal connections of the battery wires is broken. Check the condition of the battery terminals and terminal lugs of the wires, carefully clean the contact surfaces, make sure that the lugs fit and fasten on the terminals.
3. Serviceability of functioning of the generator/voltage regulator is broken. Check, make the necessary remedial repairs, or replace the failed components.
4. The fastening of the terminal connections of the electrical wiring on the generator is loose, the quality of the grounding is broken, or the contact terminals are excessively oxidized. Check the condition of the contact connections, clean the terminals, replace the failed components.
5. The alternator drive belt is worn out or its tension is loose. Check, tighten or replace the belt, replace defective tensioner components.
Battery drains when car is parked overnight
1. The battery is defective. Replace with a known good battery.
2. There are electrical leaks. Check that all lighting and signaling devices are switched off (both external and internal), if necessary, replace the failed sensors-switches.
3. The components of the diode assembly of the generator are out of order. Check, replace the defective alternator.
Tips for Diagnosing Recoil Loss Problems
First of all, the general mechanical condition of the power unit should be assessed.
The functioning of the fuel supply control system on injection models is based on constant monitoring of the air-fuel mixture supply, based on the continuous transmission of data from information sensors to the control module. Unlike carburetor models, where the energy developed by the air flow sucked into the engine is used to push the 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 the opening of the injectors through which the fuel is fed into the pipeline/inlet ports of the combustion chambers.
Management is based on the analysis of data continuously coming from the relevant information sensors. Sensors monitor parameters such as the operating temperature of the coolant, the temperature and amount of air drawn into the engine, crankshaft speed, current throttle position, etc. the control unit continuously analyzes the incoming information and determines the duration of the opening of the injection injectors required at the current time. The sensors generate low-voltage signals, and therefore, a violation of the quality of the contact connections of the electrical wiring of the corresponding connecting circuits can have the most direct impact on the efficiency of the engine output (comparable to the impact exerted by the failure of sensors).
When diagnosing failures related to the correct operation of the injection system, always first check the condition of the corresponding electrical wiring of its contact connections. Make sure the electrical connectors are securely fixed, periodically check their physical condition. Try not to use chemicals that are 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 cleaned components, the presence of which is unacceptable, in addition, there is a high risk of damage to the insulation of the electrical wiring.
The engine electrical system provides power supply to all onboard consumers, electronic control units, information sensors and actuators. Due to the extreme sensitivity of the elements of the engine control system to voltage drops, a malfunction of the generator / voltage regulator can lead to a noticeable decrease in the efficiency of the output of the power unit. The cars covered in this Guide are usually equipped with generators with a built-in voltage regulator. The operating parameters of this kind of regulators are not subject to adjustment and in case of violations, it is necessary to replace the corresponding element (regulator or generator) assembled.
The functioning of the ignition system is also firmly connected with the operation of the fuel injection / engine management system and is based on the use of data from the corresponding information sensors by the control module. Based on the analysis of the information coming from the sensors, the control module makes timely adjustments to the ignition timing, achieving optimal engine operation at any speed and current loads. On most modern systems of this kind, manual adjustment of the ignition timing is no longer possible. In the event of a malfunction in the functioning of such a system, the failed element must be replaced - 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 proprietary cleaners.
Diagnosis of malfunctions of the cooling system
Note. Mechanical failures of the power unit can also be the causes of some of the problems in the functioning of the cooling system. So, a violation of the integrity of the cylinder head gasket, or the formation of a block casting porosity, as a rule, inevitably leads 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, one should not forget to check the condition of the corresponding fuses and the quality of the contact connections of the fan operation 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 performance to check the path for air pockets. "Upgrade" 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 poorly developed leaks in the cooling system path. Check the tract with pressure - leaks can be identified by ear by a characteristic hiss. Particular attention should be paid to the condition of components such as connecting hoses (with fastening clamps), valve for controlling the supply of coolant to the heater heat exchanger, the heat exchanger itself (radiator) heater, radiator, radiator hoses and water pump. Replace defective elements, add the required amount of coolant of the required grade to the system.
3. The serviceability of the functioning of the electrical control device for the functioning of the cooling system fans is broken (on corresponding models). Check the condition of the relevant fuses, relays and temperature sensors. Replace failed components.
4. There are leaks of coolant through the cylinder head gasket, or as a result of the development of porosity in the walls of the casting of the block or cylinder head. Check, replace the gasket, or the defective section of the power unit.
5. The patency of the radiator heat exchanger is broken. Flush or replace the radiator.
6. Faulty water pump. If there is a violation of the adequacy of the circulation of the coolant, check the tightness of the fit of the water pump rotors, in case of slack, replace the pump.
Engine coolant level keeps dropping
1. There are weakly developed leaks in the cooling system path. Check the tract with pressure - leaks can be identified by ear by a characteristic hiss. Particular attention should be paid to the condition of components such as connecting hoses (with fastening clamps), valve for controlling the supply of coolant to the heater heat exchanger, the heat exchanger itself (radiator) heater, radiator, radiator hoses and water pump. Replace defective elements, add the required amount of coolant of the required grade to the system.
2. There are leaks of coolant through the cylinder head gasket, or as a result of the development of porosity in the walls of the casting of the block or cylinder head. Check, replace the gasket, or the defective section of the power unit.
Engine overcooling occurs
1. Faulty thermostat. Replace stuck open thermostat.
2. The functioning of the electrical control device for the functioning of the cooling system fans is broken (on corresponding models). Check the condition of the relevant fuses, relays and temperature sensors. Replace failed components.
3. The readings of the temperature meter are inaccurate. Check the condition of the temperature sensors, eliminate the identified problems.
The engine is running hot
1. The patency of the radiator heat exchanger is broken. Flush or replace the radiator.
2. The water pump drive belt is worn out or its tension is loose. Check, tighten or replace the belt, replace defective tensioner components.
3. Serviceability of functioning of fans of system of cooling is broken. Check the condition of the drive motors, relays and temperature sensors. Replace defective components.
4. The readings of the temperature meter are inaccurate. Check the condition of the temperature sensors, eliminate the identified problems.
5. Dropped coolant level. Turn on the interior heater to maximum performance to check the path for air pockets. "Upgrade" 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 system of release of the fulfilled gases
Note. The increase in the level of vibrations associated with violations in the exhaust system should not be neglected. Remember that an increase in the vibration background leads to premature wear of the components of the suspension supports of the power unit, the formation of cracks and fatigue deformation of the metal components of the frame and suspension, the destruction of welds and the core of the catalytic converter.
There is a characteristic thud when the engine is idling
1. Worn powertrain suspension mount components. Inspect the support nodes, replace the failed components, tighten the fasteners.
2. The components of the suspension supports of the elements of the exhaust system are faulty. Inspect the support nodes, replace the failed components, install new ones to replace the lost ones.
3. There is mechanical damage to the muffler or catalytic converter. It should be borne in mind that the detached internal elements of these components can be carried down the exhaust gas flow down the path, making characteristic sounds far enough from the defective assembly. 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 piping. Remove the suspect sections of the exhaust system, remove all loose and foreign objects from the path, replace the failed components.
4. Check the correct laying of the working sections of the exhaust system, paying special attention to the adequacy of the gaps between the elements of the system and the components of the body / suspension.
During driving, vibrations occur in the components of the exhaust system
1. The components of the suspension supports of the elements of the exhaust system are faulty. Inspect the support nodes, replace the failed components, install new ones to replace the lost ones.
2. The correct laying of the working sections of the exhaust tract is violated. Evaluate the adequacy of the gaps formed between the elements of the system and the components of the body / suspension.
Sections of the exhaust system hung excessively low under the bottom of the vehicle
1. The components of the suspension supports of the elements of the exhaust system are faulty. Inspect the support nodes, replace the failed components, install new ones to replace the lost ones.
2. The correct laying of the working sections of the exhaust tract is violated.
The functioning of the exhaust system is accompanied by excessive background noise
1. The reliability of fixing the components of the exhaust tract is broken, or there are exhaust gas leaks. Carefully inspect the system along its entire length, eliminate the identified problems, replace defective components.
2. The internal dividing walls of the exhaust tract mufflers are destroyed. Check the condition of suspect components, replace defective units.
3. A failed muffler was replaced with a tubular section due to unscrupulous 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 operation of the AT is controlled electronically. In this case, the condition of the electrical wiring and contact connections of the corresponding circuit is of paramount importance. Do not forget to inspect the relevant components from time to time, check that the connectors are securely fixed. To wipe the insulation and remove oxidation products from the contact terminals of the electrical wiring, use only proprietary cleaners!
The smoothness of switching AT is broken
1. Dropped transmission fluid level. Check and make appropriate adjustments if necessary.
Attention! Only use ATF of the recommended grade!
2. Check the condition of the ATF. If signs of contamination are found, replace the fluid and the AT filter. The presence of a burning smell in the liquid indicates the fact of slipping of the internal components of the transmission. It is more correct to entrust the performance of a condition check and restoring repair of the AT to car service specialists.
3. The AT filter is installed incorrectly, or its sealing gasket is destroyed. Check, make necessary corrections, replace defective components.
4. The tightness of sealing gaskets or pressure lines / their fittings is broken. Check up a condition of components of a hydraulic path АТ, make necessary corrections, replace defective components.
5. Loose fastening of the AT/throttle switch drive rods. Check, make necessary corrections, tighten fasteners.
Serviceability of switching АТ is broken
1. The fastening is loose / the adjustment of the AT switching drive rods is disturbed. Check and make necessary corrections/adjustments.
2. Dropped transmission fluid level. Check and make appropriate adjustments if necessary.
Attention! Only use ATF of the recommended grade!
3. There is damage to the internal components of the transmission. It is more correct to entrust the performance of a condition check and restoring repair of the AT to car service specialists.
AT does not automatically switch to a lower gear when the gas pedal is pressed to the floor
1. Faulty sensors or control units (models with electronic control AT). Check, make necessary corrections, replace defective components.
2. The adjustment of the drive rods for switching on the kickdown mode is broken, or the vacuum servo drive is faulty (kickdown models). Check the condition of the drive components, make the necessary corrections, replace the defective components.
3. On models with electronic control.
4. "sank" diaphragm spring (see chapter Clutch and transmission line).
5. Hydraulic fluid is leaking from the clutch master or slave cylinder (see chapter Clutch and transmission line).
6. Air got into the hydraulic circuit of the clutch drive (there is softness of the pedal) (see chapter Clutch and transmission line).
7. The sealing collar 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 pilot bearing (see chapter Clutch and transmission line).
Manual gearbox
Gear shifting is accompanied by a rattle
1. Worn clutch release drive components. On models with a mechanical or cable-operated clutch, check the adjustment of the relevant components. Adjust the clutch pedal so that its free play does not exceed 25 mm. On models with hydraulic clutch control, check the fluid level in the master cylinder reservoir and correct if necessary.
2. Worn synchronizers. Remove a transmission, replace synchronizers.
3. Synchronizer sliding sleeves worn out. Remove gearbox, replace sliding clutches.
4. Worn or damaged gear pawls. Remove the gearbox, replace the corresponding gears.
Box "jumps off" from selected gear
1. Worn shift rod locking springs. Replace failed components.
2. Synchronizer sliding sleeves worn out. Remove gearbox, replace sliding clutches.
3. Worn or damaged gear pawls. Remove the gearbox, replace the corresponding gears.
4. Worn crankshaft thrust bearings. Disassemble the engine, replace the failed components.
Difficulty shifting gears
1. Broken clutch adjustment. Check and make appropriate adjustments if necessary.
2. Worn synchronizers. Remove a transmission, replace synchronizers.
3. Stuck guide bearing. Remove the gearbox, replace the bearing.
4. Gearshift linkages/bushings jammed. Disassemble shift drive mechanism, replace worn and defective components. During assembly, do not forget to carefully lubricate the parts to be installed.
Transmission oil leaks
1. Too much oil in the gearbox. Check the oil level, make any necessary adjustments.
2. The patency of breathers or ventilation pipes is impaired. Check, eliminate blockages, if necessary, add the required amount of gear oil to the gearbox.
3. The tightness of the sealing gasket of the gearbox crankcase is broken, or pores / cracks have formed in the casting of the latter. Replace defective components. Pour the required amount of oil of the required grade into the gearbox.
Clutch
Note. The clutch drive can be carried out by means of rods, cable or hydraulically. On models with a mechanical or cable drive, the amount of pedal free play should occasionally (as the driven disk wears out) be corrected. On models with hydraulic drive, adjustment is automatic (except for the height of the pedal position, which is not subject to adjustment).
Clutch slips when driving uphill or during acceleration
1. The adjustment of the free travel of the clutch pedal is broken. Check that by adjusting the linkage/drive cable, achieve that the free play of the pedal is about 25 mm.
2. Worn/damaged clutch disc. Remove engine/gearbox, replace clutch assembly.
3. Weakened petals of the diaphragm spring of the clutch pressure plate. Remove engine/gearbox, replace clutch assembly.
4. The quality of the machining of the working surfaces of the pressure plate / flywheel is broken. Check and replace defective components.
Completeness of switching off of coupling is broken (gear shifting is difficult)
1. Faulty clutch release drive mechanism. Assess the condition of the drive elements (cables/rods/components of the hydraulic path), replace defective parts. On models with hydraulic clutch "pump" fluid tract, completely removing air plugs from it.
2. Damaged clutch release lever or its swivel assembly. Check the condition of the lever, replace if necessary.
3. The hub of the clutch disc is damaged, or its torsion springs. Disassemble the clutch, replace the failed components.
4. Stuck clutch guide bearing. Disassemble the clutch, replace defective components.
5. Faulty driven disk. Disassemble the clutch, evaluate the flatness of the driven disk, make sure that the thickness of the friction linings does not exceed the maximum allowable value. Replace related components.
Depressing the clutch pedal is accompanied by extraneous noise
1. The adjustment of the pedal stop or its free play is broken. Check and make appropriate adjustments.
2. Worn or damaged release bearing. If the background noise decreases when the pedal is released, the bearing should be replaced.
3. Excessive axial play of the crankshaft of the engine. Check the condition of the crankshaft thrust bearings, replace defective components.
Clutch pedal requires too much force to depress
1. Stuck pedal axle. Check, eliminate the causes of blockage, replace defective components, lubricate the axle bushings.
2. Incorrectly routed or worn clutch cable (cable driven models). Assess the condition of the drive cable, in case of pins, scuffs, signs of corrosion and other damage, replace the cable, being careful not to excessively bend the new one. Check the quality of the grounding of the power unit - when the bus is disconnected, the grounding may begin to be carried out along the clutch cable, which leads to its premature wear.
3. On models with a mechanical clutch drive, check the correct laying of the rods, make sure that there are no signs of jamming. Lubricate axle and anchor points, replace defective components.
4. There is a lack of lubrication of the guide tube of the release bearing and the clutch release fork. Check, pack appropriate components with heat-resistant grease, achieving full freedom of movement of the bearing on the tube.
5. On models with a hydraulic clutch drive, check the fluid level, inspect the surfaces of the clutch master and slave cylinders for signs of leakage. Replace defective components, "pump" hydraulic path. If there are no signs of fluid leaks, it can be assumed that there is internal damage to the clutch master cylinder. Replace the cylinder "pump" system.
Clutch engagement is accompanied by vibration
1. The flatness of the working surface of the flywheel is broken. Check, if necessary, give the flywheel to the groove, or replace it.
2. The clutch disc is deformed, or its damper hub is damaged. Remove clutch, replace defective components.
3. The clutch pressure plate is damaged, or the petals of its diaphragm spring are weakened. Replace pressure plate.
Differential and final drive
The differential emits a low frequency rattle
1. The level of the lubricant has fallen, or the wrong grade of oil has been poured into the differential. Check and change oil if necessary.
2. Worn or damaged differential bearings. Replace bearings, check the condition of the drive and driven gears, if necessary, replace them as well.
The functioning of the differential is accompanied by a howling sound
1. The level of the lubricant has fallen, or the wrong grade of oil has been poured into the differential. Check and change oil if necessary.
2. Worn or damaged differential drive and/or driven gear. Check and replace defective components.
Transfer case
After a trip, traces of lubricant leakage through oil seals or a breather are detected
1. Transfer case filled with too much lubricant. Check fluid level, correct if necessary.
2. The patency of the breather or its hose is broken. Check, eliminate the reason for blocking the ventilation duct, if necessary, add the required amount of liquid of the required grade to the transfer case crankcase.
3. Worn or damaged oil seals. Replace defective components, check the lubricant level, correct if necessary.
The operation of the transfer case is accompanied by an intense background noise
1. Wrong grade of lubricant filled into transfer case. Empty the box, fill it with the correct liquid.
2. Lubricant level dropped. Check and make appropriate adjustments if necessary.
3. There is damage to the internal components of the transfer case. Remove the box, disassemble it, evaluate the condition of the internal components, replace defective parts.
Transfer case jumps from selected position
1. Stop moving and make sure that the box is fully engaged.
2. There is wear, loose fastening, or drive rod adjustment is broken. Check the condition of the transfer box drive, make the necessary corrections / adjustments / replacements.
3. Has wear or damage to the internal components of the transfer case.
4. Remove the box, disassemble it, evaluate the condition of the internal components, replace the defective parts.
Cardan shaft (rear wheel drive and all wheel drive models)
Note. The cardan shaft sections are usually interconnected by means of universal (cardan) hinges, however, on some models, constant velocity joints or rubber flexible couplings can be installed instead of the latter.
Gear shifting from front to rear is accompanied by a dull metallic click in the central part of the bottom of the car
Worn driveshaft cross. Remove the shaft, replace defective components.
Acceleration of the car is accompanied by vibrations in the central part of the car
1. Worn driveshaft cross. Remove the shaft, replace defective components.
2. The correct installation of the cardan shaft is violated. Check the condition of the suspension mounts of the power unit, tighten the fasteners, replace the defective components.
3. The balance of the cardan shaft is broken as a result of deformation or bending. Check and replace defective components.
4. There was an unbalance of the cardan shaft. Remove the shaft assembly and give it to balancing. Alternatively, replace the shaft.
Drive shafts/axles
Turning the front / rear wheels while driving is accompanied by clicks
1. Foreign objects are stuck in the tread pattern. Check, clean the tread, if necessary, take the wheel in for repair.
2. Worn/damaged CV joints (CV joints), or loosened their fastening on the drive shafts. Assess the condition of the CV joints, if necessary, replace.
Vehicle acceleration is accompanied by a noticeable vibration of the front / rear wheels
1. The rim is deformed. Check, if necessary, return the corresponding wheel for repair, or replace the defective disk.
2. The wheels are out of balance. Balance the wheels.
3. Worn wheel bearings or loose preload. Check, if necessary, replace the bearings, adjust the preload.
4. Worn/damaged CV joints (CV joints), or loosened their fastening on the drive shafts. Assess the condition of the CV joints, if necessary, replace.
Other problems associated with the operation of the transmission line
When the car accelerates, there is a burning smell emanating from under the central part of the bottom
1. Jammed brakes. Check, evaluate the clearance of the pistons in the caliper cylinders and the degree of wear of the working surface of the brake disc (see also Brake Troubleshooting Section).
2. Clutch slips (models with manual transmission). Check and make appropriate corrections (see above).
3. Dropped ATF level (models with AT). Check and make appropriate adjustments if necessary. If adjusting the fluid level does not resolve the odor, the transmission must be removed for an appropriate rebuild.
The increase in engine speed is not accompanied by acceleration of the car
1. Clutch slips (models with manual transmission). Check and make appropriate corrections (see above).
2. Dropped ATF level (models with AT). Check and make appropriate adjustments if necessary. If correcting the fluid level does not correct the situation, the transmission should be removed for appropriate reconditioning.
Diagnostics of malfunctions of the brake system
Note. Before concluding that the brake system has failed, check the condition and inflation pressure of the tires, the vehicle's load evenness, and the front wheel alignment.
Depressing the brake pedal is accompanied by jerking or pulsing
1. Loose wheel nuts. Check that the wheel nuts are evenly tightened to the required torque.
2. Deformed or unevenly worn brake disc. Check, if necessary, make a groove or replace a defective disk.
Attention! The groove of the disk should not lead to a decrease in its thickness below the permissible limit!
3. The bolts of the brake caliper or its anchor bracket have loosened. Check, tighten the fasteners with the required force, evaluate the condition of the load-bearing components.
4. Loose wheel bearing preload. Check, adjust accordingly, replace bearings if necessary.
During braking, a characteristic high-frequency squeal of the brakes occurs
1. From the outer edge of the brake disc (ov) furrows have formed. Check, if necessary, make a groove or replace a defective disk.
Attention! The groove 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 pads are dirty. Remove the pads, clean the pads thoroughly.
3. Excessively worn pads. Check, replace.
4. The working surface of the friction linings is polished to a shine. Check, replace pads / shoes complete with brake discs / drums.
5. Corroded fasteners for brake pads/boots. Check, replace defective components, lubricate installed parts with heat-resistant grease before reassembly.
During braking, a grinding occurs in the central part of the wheels
1. Excessively worn pads. Check, replace.
2. Partially or completely seized brake components causing premature and uneven brake pad/shoe and disc/drum wear. Check and replace defective components.
During braking, the directional stability of the vehicle is lost (vehicle pulls to the right or left)
1. Air has entered the hydraulic path of the brake system. Carefully inspect all system components for signs of leaks. Bleed the appropriate part of the hydraulic path. Change brake fluid.
2. Passability of flexible brake hoses is broken. Check, replace defective components, flush the hydraulic path.
3. Partially or completely seized brake components causing premature and uneven brake pad/shoe and disc/drum wear. Check and replace defective components.
4. The geometry of the front end of the car is broken, or the suspension components are excessively worn out. Check, replace defective components, tighten fasteners, adjust the angles of the front wheels.
5. Faulty drum brake regulators. Check, eliminate the causes of blocking, replace defective components, adjust the brakes.
There is softness or excessive travel of the brake pedal
1. The level has dropped, or there is contamination of the brake fluid. Check. If the brake path has not been flushed for more than two years, clean the walls of the GTZ reservoir, flush the brake system, fill it with fresh fluid and pump it.
2. Damaged flexible brake hoses. Check and replace defective components.
3. Faulty drum brake regulators. Check, eliminate the causes of blocking, replace defective components, adjust the brakes.
Braking efficiency is clearly underestimated, despite the increased resistance of the foot brake pedal to squeezing
1. Faulty vacuum brake booster. Check, assess the condition of the servo control valve, replace defective components.
2. The working surfaces of the friction linings of the brake pads are polished to a shine. Check, replace the pads, if necessary, eliminate defects in the working surfaces of the brake discs / drums.
3. Partially or completely seized brake components causing premature and uneven brake pad/shoe and disc/drum wear. Check and replace defective components.
Disturbed uniform distribution of braking force between the front and rear wheels of the car
1. Worn, damaged, or stuck control valve. Replace valve.
2. Jammed, the beater is disconnected the spring / thrust of the drive valve-regulator. Check and replace defective components.
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 path components for signs of leaks, replace defective parts, add the required amount of fluid to the GTZ reservoir, bleed the brake system.
2. Faulty GTZ. Replace the cylinder, fill the system with fresh brake fluid, bleed the hydraulic path.
Brake fluid smells like burning
1. Partially or completely stuck brake components. Check and replace defective components.
2. Passability of flexible brake hoses is broken. Check, replace defective hoses, flush the hydraulic path, bleed the system.
3. Faulty parking brake release mechanism. Check the condition of the drive cables and actuating levers, replace defective components.
Tips for Diagnosing Brake Problems
Causes of pulsations and vibrations that appear 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 reason for their appearance is uneven wear or deformation of the discs / drums of the brake mechanisms of the rear wheels. Recoil in the steering wheel indicates the need to first check the condition of the brake discs of the front wheels.
Pedal failures during braking may be associated with air entering the hydraulic tract of the system, or with boiling of the working fluid as a result of "tacking" 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, while holding it depressed, cock the parking brake, then release the pedal and immediately squeeze it back. If, when you depress the pedal again "fails", hence the rear brakes need to be adjusted.
Note. Do not compensate for misadjustment of drum brakes by adjusting the parking brake, as this will cause premature wear of the brake shoe linings.
Diagnosis of malfunctions of wheels, tires, steering gear and suspension
Wheels and wheel bearings
Loose front wheels/wheel bearing preload
All-wheel drive and front-wheel drive models
1. Loose hub/wheel nuts. Check, tighten fasteners.
2. Worn or damaged wheel bearings. Check, if necessary, replace, adjust the bearing preload.
Rear wheel drive models
1. Adjustment of wheel bearings is broken. Adjust preload, if slack persists, replace bearings.
2. Loose wheel nuts. Check, tighten fasteners.
3. Worn or damaged wheel bearings. Check, if necessary, replace, adjust the bearing preload.
Loose rear wheels/wheel bearing preload
All-wheel drive and rear-wheel drive models
1. Loose hub/wheel nuts. Check, tighten fasteners.
2. Worn or damaged wheel bearings. Check, if necessary, replace, adjust the bearing preload.
Front wheel drive models
1. Adjustment of wheel bearings is broken. Adjust preload, if slack persists, replace bearings.
2. Loose wheel nuts. Check, tighten fasteners.
3. Worn or damaged wheel bearings. Check, if necessary, replace, adjust the bearing preload.
Tires
There is one-sided tread wear
1. Violated wheel alignment (convergence). Check and make any necessary adjustments.
2. Tires not properly inflated. Check and make appropriate adjustments.
3. Worn or damaged suspension components. Check, replace defective parts, adjust wheel alignment.
There is uneven tread wear
1. Tires are incorrectly inflated or the wheels are out of balance. Check and make any necessary adjustments.
2. The adjustment of the wheel alignment angles is broken. Check and make any necessary adjustments.
3. Defective shock absorbers. Check the condition of the suspension struts, replace defective components. Adjust wheel alignment.
4. Violated wheel alignment (convergence). Check and make any necessary adjustments.
5. Worn or damaged suspension components. Check, replace defective parts, adjust wheel alignment.
Steering gear
There is excessive play in the steering wheel
1. Adjustment of a free wheeling of the steering mechanism is broken. Check and make appropriate adjustments.
2. Worn or damaged steering gear components. Check, replace defective parts, adjust the angles of the front wheels.
3. Faulty steering gear. Check, replace, adjust the angles of the front wheels.
Steering wheel vibrates when driving at cruising speed
1. Deformed discs / tires of the front wheels. Check, replace defective disks, balance wheels.
2. There is uneven wear on the front tires. Replace tires, make sure they are properly inflated.
3. There is a hidden defect in the tires of the front wheels. Replace tires, make sure they are properly inflated.
4. The balance of the front wheel assemblies is broken. Balance the wheels. Make sure the wheel bolts/nuts are tightened to the correct torque.
5. Loose wheel bearings. Check, adjust the preload, if necessary, replace the failed bearings.
Steering wheel vibrates when braking
See the section on brake system troubleshooting above.
Steering wheel requires excessive force to turn
1. Steering wheel free play adjustment is broken. Check and make appropriate adjustments.
2. Faulty steering gear. Replace rack and pinion assembly, adjust front wheel alignment.
3. Worn or damaged suspension components. Check, replace defective parts, adjust the angles of the front wheels.
Suspension
Violated directional stability of the car
1. Tires are unevenly inflated. Check and make appropriate adjustments.
2. There is uneven wear of the protectors. Check, replace tires.
3. Wheels of different sizes are installed on the front axle of the car, or the weight balance of the tires is disturbed. Check and make any necessary replacements.
4. The adjustment of the angles of installation of the front wheels is broken. Check and make appropriate adjustments.
5. "tacked on" brakes. Check the condition of the brake mechanisms, replace defective components, adjust the angles of the front wheels.
Vehicle sways excessively when driving on uneven road surfaces
1. Worn or seized shock absorbers or other strut assembly components. Check and make necessary corrections/replacements.
Note. Shock absorbers are usually replaced in pairs.
Vehicle rolls excessively when cornering
1. Worn or seized shock absorbers or other strut assembly components. 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 vehicle is excessively rough
1. Stuck shock absorbers. Check the condition of the suspension struts, replace defective components.
2. Tires are overinflated. Check, relieve excess pressure.
The car has an excessively low landing, or is tilted to one side
1. Suspension coil springs damaged or sagged. Check and, if necessary, replace the springs in pairs.
2. Stuck shock absorbers. Check the condition of the suspension struts, replace defective components.
Extraneous noise and vibration
The movement of the car is accompanied by clicks
1. Check whether there is a relationship between the intensity of sounds and the speed of the car, whether clicks disappear when coasting. If the clicking frequency changes in proportion to the driving speed, and does not depend on the position of the gas pedal/steering wheel, check if there is a foreign object stuck in the tread pattern of any of the tires. If necessary, take the wheel to a tire shop.
2. If there is a relationship between the intensity of sounds and speed / throttle / steering wheel position, check the condition of the CV joint, universal joint / flexible coupling of the propeller shaft.
Knocking and clicking when driving on uneven road surfaces
1. Loose or damaged suspension components. Check (special attention should be paid to the condition of rubber-metal bushings and ball bearings), replace defective parts.
2. Loose suspension component bolts. Check the tightness of the fasteners of the subframe and the bolts of the axle joints of the suspension elements. Tighten fasteners with the required force.
3. Loose wheel bearings. Adjust preload, replace bearings if necessary.
4. Adjustment of door loops is broken. Check the tightness of the doors, if necessary, make the appropriate adjustments, tighten the hinge fasteners.
The movement of the car is accompanied by a low-frequency rumble
1. These kinds of sounds are usually a sign of failure of transmission line bearings, mainly wheel bearings. The cause of bearing failure may be their overheating caused by "tacking" brakes, as well as damage from hitting a curb or sewer. During cornering, the noise intensity can vary, so when turning left, the load on the right wheel bearing increases and vice versa. Another sign of front wheel bearing failure is the appearance of steering wheel vibrations when cornering. Damaged wheel bearings must be replaced.
2. Excessively worn/damaged tires or out of balance wheels. An internal tire defect is sometimes accompanied by symptoms similar to those of damaged suspension components. Install a known-good set of wheels.
When driving on uneven road surfaces, a characteristic metallic creak 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 bearings, if there is any slack, replace it. Don't forget to adjust the wheel alignment.
2. The rubber-metal bushings of the support components of the suspension are destroyed. Check, replace defective components, adjust wheel alignment.
3. Twisted on the rod rubber bushings of the stabilizer bar / jet rod. Check the condition of the bushings, replace if necessary. When installing, lightly grease the seating surfaces of the bushings.
Vehicle movement is accompanied by vibration
1. Vibrations are caused by uneven road surfaces.
2. Worn/damaged tires or out of balance wheels. Balance the wheels. Replace if necessary.
3. Damaged joints (CV joint, universal joint or flexible coupling) cardan shaft. Check and replace defective components.
4. Drive shaft is bent or loose. Check, tighten fasteners, replace if necessary.
Diagnostics of failures of onboard electrical equipment
Headlights
One or both headlights are malfunctioning in low or high beam mode
1. The quality of the contact connection on the connector is broken. Check the quality of the grounding of the headlight and the serviceability of the power supply to it from the battery. If the power is good and the ground is good, replace the failed lamp. If there is a power/ground fault, check the condition of the wiring in the relevant circuit (see wiring diagrams).
2. Faulty control switch. Make a replacement.
The brightness of one or both headlights is severely reduced
1. The quality of the contact connection on the connector is broken. Check the quality of the grounding of the headlight and the serviceability of the power supply to it from the battery. If the supply voltage at the connector is very low, check the condition of the elements and the connecting wiring of the corresponding circuit.
2. The base of the corresponding lamp or its socket is badly oxidized. Thoroughly clean the contact surfaces, if necessary, replace the failed component.
Running and marker lights
Running and parking lights do not work
1. The quality of the contact connection on the connector is broken. Check the grounding of the corresponding lighting fixture and the correct battery power supply. If the power is supplied properly and the grounding is in order, check the condition of the cartridge, if necessary, replace the failed lamp. If there is a power/ground fault, check the condition of the wiring in the relevant circuit.
2. Faulty control switch. Make a replacement.
There are intermittent failures of navigation and position lights
1. The filament of the corresponding lamp is damaged. Check, replace the failed lamp.
2. The base of the corresponding lamp or its socket is badly oxidized. Thoroughly clean the contact surfaces, if necessary, replace the failed component.
3. Damaged wiring or its contact terminals. Check and make appropriate corrections.
4. Faulty control switch. Make a replacement.
The brightness of the glow of one of the lighting fixtures is greatly reduced
1. The quality of the contact connection on the connector is broken. Check the grounding of the corresponding lighting fixture and the correct battery power supply. If the supply voltage at the connector is very low, check the condition of the elements and the connecting wiring of the corresponding circuit (see wiring diagrams).
2. The base of the corresponding lamp or its socket is badly oxidized. Thoroughly clean the contact surfaces, if necessary, replace the failed component.
3. Faulty control switch. Make a replacement.
Interior lighting fixtures
Interior lighting not working
1. The control switch is set to the wrong position. Find the switch and move it to the appropriate position.
2. The quality of the contact connection on the lamp connector is broken. Check the grounding and battery power supply. If there is no power, check the condition of the appropriate fuse and replace if necessary. Check the condition of the elements and connecting wiring of the corresponding circuit (see wiring diagrams). If there is no grounding, check the condition of the contacts of the door sensors-switches, remove traces of corrosion, if necessary, replace the defective components.
There is an intermittent failure of interior interior lighting
1. The filament of the corresponding lamp is damaged. Check, replace the failed lamp.
2. The base of the corresponding lamp or its socket is badly oxidized. Thoroughly 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. Serviceability of functioning of door sensors-switches is broken. Check and replace failed components.
The brightness of the interior lighting is greatly reduced
1. The quality of the contact connection on the connector is broken. Check the quality of the grounding of the lamp and the serviceability of the supply of battery power to it. If the supply voltage at the connector is very low, check the condition of the elements and the connecting wiring of the corresponding circuit (see wiring diagrams).
2. The base of the corresponding lamp or its socket is badly oxidized. Thoroughly clean the contact surfaces, if necessary, replace the failed component.
3. One of the control switches/sensors is defective. Make a replacement.
Stop lights
There is a failure of one of the brake lights
The serviceability of the voltage supply to the lamp of the corresponding brake light is broken. check if the power is supplied properly, evaluate the quality of the ground, if necessary, replace the lamp. If there are signs of a break in the power circuit or ground, check the condition of the elements and the connecting wiring of the corresponding circuit (see wiring diagrams).
Both brake lights fail
The adjustment of the sensor-switch of brake lights is violated. Check and make appropriate adjustments. If the power supply to the brake lights remains broken despite the correct functioning of the sensor-switch, check the condition of the elements and the connecting wiring of the corresponding circuit (see wiring diagrams), make the necessary corrections.
The brightness of one or both brake lights is severely reduced
The quality of the contact connection on one of the contact connectors of the corresponding circuit is broken. Check the quality of the grounding of the lamp assemblies and the serviceability of the supply of battery power to them. If the supply voltage at the connector is very low, check the condition of the elements and the connecting wiring of the corresponding circuit (see wiring diagrams). Sometimes it becomes necessary to remove a defective connector and clean its seating surface.
Pilot lamps
Pilot lamp (s) stays on after starting the engine
Charge control lamp
1. Faulty alternator or voltage regulator. Check and replace failed components.
2. There is a short circuit in the electrical wiring circuit of the corresponding lamp. Check and make any necessary corrections.
Pilot lamp "Check engine"
1. The time has come for the next maintenance of the engine, or the settings of the latter are violated. Carry out maintenance, check the settings, evaluate 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 re-leaning of the air-fuel mixture as a result of approaching the end of the fuel supply in the tank. Fill the car with fuel, reset the lamp.
3. The quality of the contact connections in the injection / engine control circuit is broken. Check the condition of the wiring and connectors of the control module and information sensors.
4. There are vacuum losses in the intake manifold. Check the condition of the gasket and vacuum hoses. Replace defective components.
5. There is an increased consumption of engine oil as a result of severe wear of the internal components of the engine. Rebuild the power unit.
ABS warning lamp
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 any necessary corrections.
2. There are leaks in the GTZ. Inspect the cylinder, replace the failed cuffs and gaskets.
3. The ABS control module, hydraulic pump, or control valves are malfunctioning. Check the condition of the components, make any 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 the identified defects.
Brake warning lamp
1. The level of hydraulic fluid in the GTZ reservoir has dropped. Check the hydraulic path of the brake system for signs of leaks, eliminate the identified problems, add the required amount of fluid of the required grade to the reservoir.
2. Excessively worn brake linings/boots. Check and replace failed components.
Attention! The replacement of brake pads / shoes is always carried out as a set for both wheels of the respective axle!
3. There is a defect in the control lamp signal sensor circuit. Check, make the necessary corrections, replace failed components.
Oil pressure warning lamp
Attention! Operating a vehicle with reduced oil pressure can result in serious internal engine damage resulting in 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 lamp comes on, stop the engine immediately and check the engine oil level and the condition of the oil filter. If necessary, add an appropriate amount of oil from a canister that must be kept in the vehicle and refilled at every oil change.
5. The wiring of the sensor-switch of the oil pressure control lamp is damaged. With the ignition on (do not start the engine) disconnect the wiring from the sensor-switch - the control lamp should not burn, otherwise check the wiring for signs of a short circuit to ground. Make sure the integrity of the insulation along the entire length of the wires, replace the defective circuit elements.
6. The patency of the mesh filter of the oil intake is broken. Remove the oil pan and clean the filter.
7. Serviceability of functioning of the gauge-switch of a control lamp of pressure of oil is broken. Install beforehand to check
8. The full flow oil filter is blocked or there are oil leaks. Replace filter.
Control lamp of a cocking of a parking brake
1. Parking brake lever not released. Remember to release the parking brake before driving off.
2. The installation position of the sensor-switch of the control lamp is violated, or there is a short circuit in the circuit of its electrical wiring. Check and fix the identified problems.
3. The gauge switch of a control lamp is faulty. Check, replace.
Pilot lamp (s) starts flashing while driving
Charge control lamp
1. Faulty alternator or voltage regulator. Check and replace failed components.
2. There is a short circuit in the electrical wiring circuit of the corresponding lamp. Check and make any necessary corrections.
Pilot lamp "Check engine"
1. The time has come for the next maintenance of the engine, or the settings of the latter are violated. Carry out maintenance, check the settings, evaluate 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 re-leaning of the air-fuel mixture as a result of approaching the end of the fuel supply in the tank. Fill the car with fuel, reset the lamp.
3. The quality of the contact connections in the injection / engine control circuit is broken. Check the condition of the wiring and connectors of the control module and information sensors.
4. There are vacuum losses in the intake manifold. Check the condition of the gasket and vacuum hoses. Replace defective components.
5. The wiring of the control lamp circuit is damaged. Check the wiring for short circuits, fix any problems found.
ABS warning lamp
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 any necessary corrections.
2. There are leaks in the GTZ. Inspect the cylinder, replace the failed cuffs and gaskets.
3. The ABS control module, hydraulic pump, or control valves are malfunctioning. Check the condition of the components, make any 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 the identified defects.
Brake warning lamp
1. The level of hydraulic fluid in the GTZ reservoir has dropped. Check the hydraulic path of the brake system for signs of leaks, eliminate the identified problems, add the required amount of fluid of the required grade to the reservoir.
2. Excessively worn brake linings/boots. Check and replace failed components.
Attention! The replacement of brake pads / shoes is always carried out as a set for both wheels of the respective axle!
3. There is a defect in the control lamp signal sensor circuit. Check, make the necessary corrections, replace failed components.
Oil pressure warning lamp
Attention! Operating a vehicle with reduced oil pressure can result in serious internal engine damage resulting in 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 lamp comes on, stop the engine immediately and check the engine oil level and the condition of the oil filter. If necessary, add an appropriate amount of oil from a canister that must be kept in the vehicle and refilled at every oil change.
2. The wiring of the sensor-switch of the oil pressure control lamp is damaged. With the ignition on (do not start the engine) disconnect the wiring from the sensor-switch - the control lamp should not burn, otherwise check the wiring for signs of a short circuit to ground. Make sure the integrity of the insulation along the entire length of the wires, replace the defective circuit elements.
3. The patency of the mesh filter of the oil intake is broken. Remove the oil pan and clean the filter.
4. Serviceability of functioning of the gauge-switch of a control lamp of pressure of oil is broken. Install a known-good sensor to test.
Control lamp of a cocking of a parking brake
1. Parking brake lever not released. Remember to release the parking brake before driving off.
2. The installation position of the sensor-switch of the control lamp is violated, or there is a short circuit in the circuit of its electrical wiring. Check and fix the identified problems.
3. The gauge switch of a control lamp is faulty. Check, replace.
Pilot lamp (s) does not light up when the ignition is turned on without starting the engine
1. Faulty lamp - check by substituting a known good one.
2. There is a break in the chain. Check the condition of the relevant electrical wiring.
3. The corresponding sensor-switch is faulty, or there is a defect in its electrical wiring circuit. Check, correct the identified problems, replace the defective components.
Direction indicators alarm
Warning lights come on but stay on
Breaker defective. Replace the failed unit.
There is a two-way failure of signal lights
1. Blown fuse. Check, replace.
2. The breaker is out of order - check by substituting a known good unit.
3. There is a malfunction in the wiring circuit. Check and fix the identified problems.
There is a unilateral failure of signal lights
1. Bulbs burnt out. Check and replace failed lamps.
2. The quality of the grounding of the assemblies of the corresponding lights is broken. Check, fix break.
Only one of the signal lights does not turn on
1. Bulb burnt out. Check, replace.
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, fix break.
Beacon flashing frequency greatly reduced
Too powerful lamps installed. Replace lamps.
The frequency of flashing beacons has been greatly increased
1. Insufficiently powerful lamps are installed. Replace lamps.
2. Wrong type of breaker installed. Replace breaker.
Serviceability of functioning of a control lamp of the alarm system is broken
1. Corresponding external signal lights are faulty. Check, if necessary, replace the control lamp.
2. Faulty hazard switch. Check and replace if necessary.
Serviceability of functioning of one of control lamps of indexes of turns is broken
1. Bulb burnt out. Check, replace.
2. Faulty circuit breaker - check by substituting a known good unit, replace if necessary.
Klaxon
No sound signal
1. The corresponding fuse has blown. Check and replace if necessary.
2. The serviceability of the power supply to the horn is broken, or there is a break in the ground loop. Check. If power is supplied properly, replace the horn. If a failure is detected, check the condition of the relevant electrical wiring.
Changed the tone of the horn
1. On single horn models, replace the horn.
2. On models with a 2-horn horn, check the second horn for proper operation. Alternately disconnecting the electrical wiring from the horns, check the proper functioning of each of them separately. Replace the failed component.
3. Check the correct installation of the horn (ov), - the horns must be installed with the socket down. Make sure that no foreign objects get inside the horn.
Windscreen wipers
Windshield wipers not working
1. Blown fuse. Check, replace.
2. Faulty control switch. Check, correct the identified problems, if necessary, replace the switch.
3. The quality of the contact connections in the wiper electric drive circuit is broken. Check, clean the terminals, replace the failed elements.
4. The quality of the grounding of the control switch or drive motor is broken. Check and repair any breaks found.
The drive motor overheats, turning on the wipers blows the fuse
1. There is internal damage to the electric motor. Make a replacement.
2. Jammed or deformed wiper arm drive rods. Check, make the necessary corrections, replace failed components.
The functioning of one or both wiper arms is disturbed during the correct operation of the drive electric motor
1. Loose fasteners of the corresponding drive rod. Check, tighten fasteners.
2. Loose fastening of the lever on the axis of the drive. Tighten the nut, if necessary, replace the corresponding drive arm/axle assembly.
When turned off, the brushes do not return to the parking position
1. As a result of a malfunction of the control switch, the procedure for disconnecting power from the drive motor is violated. Check and fix the identified problems.
2. There is a fault in the drive motor park circuit. Replace electric motor. Before installing the levers, run the system in order to find out the correct parking position of the wipers. After completing the installation, turn on the wipers at maximum speed and make sure that the brushes in their extreme positions do not hit the lining of the window opening.
Diagnostics of failures of a combination of devices
Cable operated speedometer
The functioning of the speedometer is completely broken
1. Drive cable not properly connected to meter assembly or drive gear. Check and make any necessary corrections.
2. The drive cable is broken or the lugs that secure it to the meter/pinion assembly are rounded off. Check and replace cable if necessary.
3. Worn speedometer drive gear. Check and replace if necessary.
4. Faulty meter - check by substituting a known-good assembly. Replace if necessary.
There are fluctuations of the meter needle when moving at a constant speed
1. The correct cable laying is broken, there are kinks or twists. Check, make the necessary corrections, if there are signs of damage to the sheath, replace the cable.
2. Cable assembly needs lubrication. Remove cable and inspect for damage (replace if necessary), lubricate and reinstall.
There are intermittent malfunctions of the speedometer
1. The completeness of the cable connection and the reliability of its fixation in the clamps are broken. Check and make any necessary corrections.
2. Worn out (rounded) cable ends. Check and replace cable assembly if necessary.
Electrical speedometer
The functioning of the speedometer is completely broken
1. Faulty inductive derailment of the speed sensor (VSS). Replace sensor.
2. Damaged wiring in the circuit between the VSS and the speedometer. Inspect the wiring, evaluate the quality of the contact connections, eliminate the identified problems, replace the defective components.
3. Damaged meter - check by substituting a known-good assembly. Replace if necessary.
There are intermittent malfunctions of the speedometer
1. The quality of the contact connections on the circuit section between the VSS and the speedometer is broken. Check, make necessary corrections, replace defective components.
2. Faulty inductive derailment of the speed sensor (VSS). Replace sensor.
Fuel consumption, engine temperature and oil pressure meters
The functioning of the meter is completely broken
1. The corresponding fuse has blown. Check, replace.
2. There is an open circuit in the electrical wiring of the corresponding meter. Check and fix the identified problems.
3. The corresponding sensor is faulty. Check, replace.
4. The adequacy of the installation of the meter or its sensor is violated. Check and make appropriate corrections.
The stability of the meter readings is broken
1. The quality of the contact connections of the corresponding electrical circuit is broken. Check and fix the identified problems.
2. The meter is defective. Make a replacement.
The meter continuously captures the maximum reading
1. There is a short to ground in the associated meter's wiring circuit.
2. The meter is defective. Make a replacement.
3. The meter's grounding is broken. Check, fix break.
4. The adequacy of the installation of the meter or its sensor is violated. Check and make appropriate corrections.
Diagnostics of malfunctions of systems of heating of an air conditioning
Heater
The functioning of the heater fan is completely broken
1. The corresponding fuse has blown. Check, replace.
2. There was a break in the wiring. Check. Correct the identified problems in the circuit.
3. There is an open in the control switch/fan resistor assembly circuit. Check and fix the identified problems.
4. Faulty fan drive motor. Check and replace if necessary.
The supply of heated air to the passenger compartment is disrupted
1. Insufficient fluid level in the engine cooling system. Check, make appropriate adjustments, remove air plugs from the cooling system path.
2. Engine does not warm up to normal operating temperature. Check the thermostat for proper operation. Check and replace thermostat if necessary.
3. Defective heat exchanger inlet valve (radiator) heater. Check the valve cable/vacuum actuator for proper operation. Several times move the temperature selection switch to the extreme positions, checking the correct operation of the valve. Warm up the engine to normal operating temperature and, having selected the maximum temperature of the heater, feel the hoses at the inlet and outlet of the valve assembly. If the hoses are at different temperatures, replace the valve.
When the heater is turned on, the windshield fogs up
1. The loosening of the mounting clamp has resulted in the development of a coolant leak from a hose laid near the bulkhead of the engine compartment or under the dashboard of the car. Check and fix the identified problems.
2. There are coolant leaks from the heater heat exchanger. Carefully inspect the floor mats in the driver's and front passenger's footwells for leaks.
Note. The coolant has a characteristic sweet smell. If necessary, make appropriate repairs or replace the failed heat exchanger. On some models to provide access to the heat exchanger (radiator) heater requires the instrument panel to be removed.
Air conditioner
Air does not flow through air conditioning vents
1. The corresponding fuse has blown. Check and replace if necessary.
2. The air conditioning system needs to be charged.
Attention! Emptying, charging and checking the refrigeration circuit must be carried out in a specialized workshop!
3. The pressure switch of the low-pressure path of the air conditioning system is faulty. Replace sensor switch.
4. Defective air conditioning fan resistor assembly. Check and replace assembly if necessary.
5. There is damage to the wiring of the air conditioning circuit, or the corresponding relay has failed. Check, eliminate the identified problems, if necessary, replace the relay.
Heated air enters through the deflectors of the air conditioning system
1. The air conditioning system needs to be charged.
Attention! Emptying, charging and checking the refrigeration circuit must be carried out in a specialized workshop!
2. Serviceability of functioning of the clutch of the K/V compressor is broken. Check the condition of the clutch and wiring of its circuit. Correct the identified problems, replace the defective components.
When using A / V on the floor in the cabin, moisture streaks are formed
1. The patency of the drainage tube of the evaporator of the air conditioning system is broken. Clean the tube where it exits the vehicle.
2. The evaporator drain hose is blocked. Clean the hose where it exits the vehicle.
The inclusion of A / V is accompanied by the appearance of a smell of mold in the cabin
The patency of the drain hose of the evaporator of the air conditioning system is broken. Clean the hose where it exits the vehicle.