| Self-diagnosis characteristics |
| The engine control unit (Motronic control unit -J220-) is equipped with fault memory. |
| When a fault occurs in monitored sensors or components, it is stored along with its fault type in the fault memory. |
| After analysing the information, the engine control unit distinguishes the different fault indexes → Chapter and → Chapter, and stores them until the fault memory is cleared. |
| Transient (sporadic) faults are printed out with the indication that it is a “sporadic fault”. These faults are displayed with the additional abbreviation “/SP”. Sporadic faults may be caused by a loose contact or transient open circuit in a wire. If a sporadic fault does not reappear in 40 warm-up phases (engine startup at coolant temperature below 50 °C and engine shutoff at temperatures above 72 °C). |
| Stored faults can be consulted with the -V.A.G 1551- or -V.A.G 1552- or with the new diagnostic unit -VAS 5051- → Chapter. |
| Once eliminated the fault(s), clear the fault memory → Chapter. |
| If the engine control unit connector is unplugged or the battery disconnected, all adaptive values of the control unit are cleared. However, the contents of the fault memory is preserved. When the engine is started up again, idling may be irregular for a brief period. In this event, let the engine idle for a few minutes or run a road test long enough for the self-adaptation process to conclude. How to proceed after an interruption in voltage supply → Chapter. |
Note! | For general information on self-diagnosis, consult the instruction manuals for the -V.A.G 1551- and -V.A.G 1552- or the new unit -VAS 5051-. |
|
|
|
