Description of On-Board Diagnostics

Diagnosis, Fault Memory - Passat

CIS-E Motronic, self-diagnosis

The procedures in this section apply to the following control units ONLY:
Starting October 1990:
49 States & Canada 8A0 907 404
California 893 907 404Q

The CIS-E Motronic control unit (J 204) features Self-Diagnosis (SD) capability. If problems occur at monitored sensors or components, they are stored in Fault memory.

The self diagnosis must be initiated and the stored fault(s) recalled with the tester VAG 1551. The VAG 1551 tester can tap into the Motronic ECU memory via remote diagnostic terminals beneath the center console in front of the shift lever.

Faults that occur only occasionally are stored as sporadic faults and are indicated in the VAG 1551 display by "SP".

If a Fault does not occur within 5 engine starts or for exhaust related faults within the next 50 starts, the sporadic fault will automatically be erased.

CAUTION! Faults related to emissions and safety are stored in a permanent memory which must be intentionally erased after faults have been eliminated or repaired.

The CIS-E Motronic control unit is also equipped with an output check diagnosis function.