Checking the technical condition
1. We make sure that there are no errors in the engine control system. Electronic control unit (ECU) engine management system has a self-diagnosis mode. When the ignition is switched on, the control lamp for a malfunction of the engine management system should light up (see «Controls and control devices»), which indicates the operability of the diagnostic system. 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. The use of a large number of information sensors makes it possible to achieve the most efficient operation of the engine, as well as to increase the reliability of the engine control system. In the event of a failure of any of the sensors, the ECU will switch to a standby mode of operation, while the engine will deteriorate to a greater or lesser extent (see «Possible car malfunctions and their causes»), however, will allow you to get to the place of repair on your own. In this case, the fault code is recorded in the computer's memory, and the engine control system malfunction indicator lamp lights up on the instrument panel. Before reading trouble codes (see below, «Troubleshooting»), we recommend that you carry out the following operations to determine the technical condition. If faults are found, they must be corrected (see relevant sections). If no faults are found during the check of the technical condition, it is necessary to carry out further fault diagnosis.
Comment. Malfunctions in the operation of the engine are not always accompanied by the glow of the warning lamp for a malfunction of the control system and vice versa.
2. We check the reliability of the connections of the connectors of the elements of the engine control system (read above about the arrangement of elements).
3. We check the integrity of the wiring harnesses in the engine compartment.
4. We check all air supply and vacuum hoses for cracks, twists and the tightness of their connections.
5. Checking the high-voltage tips of the ignition module (see «Ignition module for 1.4 and 1.6 DOHC engines - check and replacement» or «1.8 DOHC Engine Ignition Module - Check and Replace»),
6. We check the absence of smell and traces of fuel leaks.
Comment. Further checks are necessary if the engine does not start.
7. Check fuse Ef6 (see «Fuse and relay mounting blocks»). If the fuse is intact or blows again after replacement, there is a short circuit in the engine control circuit, it must be eliminated (see «Checking and repairing electrical circuits»).
8. Check relay E4 (see «Fuse and relay mounting blocks» And «Relay test»). Replace the faulty relay. If the relay is OK, then the engine control circuit is faulty (see «Checking and repairing electrical circuits»).
9. Turn off the ignition for at least 10 seconds. Then we turn on the ignition and listen to the operation of the fuel pump: after turning on the ignition, it should work for about two seconds.
Comment. The operation of the fuel pump is accompanied by a low buzz, and in order to hear it, it is necessary to minimize extraneous noise (turn off the audio system, raise the door windows, etc.)
If not, the fuel pump needs to be checked (see «Fuel pump - check and replace»).
Troubleshooting
1. When the engine control system malfunction indicator light is on with the engine running, the diagnostic code can determine the cause of the malfunction. To read fault codes, an external diagnostic device, a scanner, must be connected to the engine management system. To connect the scanner, a diagnostic connector is installed on the car, located in the lining of the floor tunnel next to the gear lever for cars with a manual gearbox or the selector for automatic transmission modes.
Astra
Zafira
To access it, it is necessary to remove the decorative trim of the floor tunnel lining (see «Parking brake lever - replacement») and remove the protective cover from the connector.
You can read fault codes at a service center that has the necessary equipment. Depending on the fault code, we check the corresponding elements of the control system and their electrical circuits (see relevant sections).
If the Malfunction Indicator Lamp goes out after starting the engine, but the engine is unstable, further steps need to be taken.
2. Check spark plugs (see «Spark plugs - check and replacement»).
3. Check the working pressure in the fuel rail (see «Fuel Pump - Working Pressure Check and Troubleshooting»).
4. We assess the technical condition of the engine (see «Engine - condition check»).
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