Electrical diagram of the accelerated pre-heating system of the 1D56T engine
1. Make sure the battery voltage is between 11-13V.
2. Make sure that the coolant temperature is not higher than 20°C.
Caution: If the coolant temperature is higher, disconnect the connector from the coolant temperature sensor.
3. Measure the electrical resistance between the electrode and the body ("ground") of the starting spark plug.
4. The resistance should be within 0.05-0.07 Ohm at an ambient temperature of 5-35°C.
Caution! The measured resistance of one spark plug is equivalent to the parallel resistance of all four spark plugs.
5. Measure the resistance between terminal "G" of the spark plug shut-off relay (1, 2) and the spark plug electrode.
6. The resistance should be within 0.14–0.16 Ohm.
Caution! Before measuring resistance, make sure that no battery voltage is applied to the relay terminal "G".
7. Connect a voltmeter to the spark plug electrode and spark plug body and measure the voltage immediately after turning the ignition key to the "ON" position (pre-heating is on) without turning on the starter.
8. After approximately 2–4 seconds, the voltage should settle within 9–11 V.
Caution: The time required for voltage reduction varies depending on the temperature of the spark plugs and the applied voltage.
9. Measure the voltage during engine starting, which should be at least 4 V.
10. Start the engine and measure the voltage during engine warm-up, which should be within 5–8 V.
11. When the coolant warms up to a temperature of 30°C or more, or if 30 seconds have passed since the engine was started, the voltage should drop to 0 V.