Fuel Injection System Diagnostics

If a fault occurs in the fuel injection or ignition systems, first make sure that all electrical connectors in the system are securely connected and not damaged by corrosion. Then make sure the fault is not caused by poor maintenance, i.e., check whether the air cleaner filter element is clean, whether the spark plugs are in good condition and the spark gap is correctly adjusted, whether the valve clearances are correctly set, whether cylinder compression is sufficient, and whether the exhaust emission control system is working properly.

If these checks do not reveal the fault, the trouble codes can be read from the memory of the electronic control unit (check whether the warning lamp is lit). After the fault is repaired, the codes can be erased from memory by removing the control unit fuse (fuse No. 24 or 25, depending on the model) for 10 seconds or more with the ignition switched on. The codes can also be erased by disconnecting the negative battery terminal, but in this case the audio system code will have to be re-entered.