Leon Mk1
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General to self-diagnosis
Features of self-diagnosis
The engine control unit (Motronic control unit J220) is equipped with a fault memory. If faults occur in the sensors and components being monitored, they will be stored in the fault memory together with an indication of the type of fault. After evaluating the information, the engine control unit decides among different faults => Fault table page 01-41 and stores these until the contents of the fault memory is erased. Faults which only occur sporadically will have the addendum "sporadic fault" on the print out. These faults will be indicated on the display by the addendum "/SP". The cause of sporadic faults can be e.g. a loose contact or a brief open circuit. If a sporadic fault does not occur again within 40 warm-up phases (engine start below 50° C coolant temperature - switched off above 72° C), it will be erased from the fault memory. The faults stored can be read-out with the new tester VAS 5051, the fault reader V.A.G 1551 or the vehicle system tester V.A.G 1552 . The fault memory must be erased after the faults has been eliminated => Page 01-17. If the engine control unit was disconnected from the battery supply voltage, switch the ignition on for approx. 10 seconds and then switch off for approx. 50 seconds. (If a throttle valve adaption has been performed the values are then permanently stored). If the connector is pulled off the engine control unit, the battery disconnected or the fault memory erased, the engine control unit will forget some learnt values. Depending on the mileage of the vehicle, this could cause engine running problems. In this case leave the engine running for a few minutes at idling speed or perform a test drive, until the learning process is completed. Note: General information for self-diagnosis can be found in the instruction manuals for the fault reader V.A.G 1551, vehicle system tester V.A.G 1552 or the new tester VAS 5051. |
