Electronic control unit (ECU) engine management system has a self-diagnosis mode. When the ignition is turned on, the engine control system malfunction indicator lamp should light up, which indicates that the diagnostic system is working. If the engine management system is working properly, then after starting the engine, the lamp should go out.
During operation, the ECU monitors the health of all elements and circuits of the engine management system. Having detected a malfunction, the ECU puts the engine management system into standby mode and turns on the engine malfunction indicator lamp located on the instrument panel. The engine will then be able to continue running (except in the case of a malfunction of the crankshaft position sensor), which allows you to get to the place of repair on your own. The ECU writes the codes of the detected faults to the RAM (RAM).
To read fault codes, an external diagnostic device must be connected to the engine management system. To do this, the system has a diagnostic connector.
You can read fault codes at a service center that has the necessary equipment.