Fault-finding

FAULT-FINDING

WARNING: Before doing any work whatsoever on system components, carefully read through the RULES OF SAFETY given previously and closely adhere to them.

System diagnosis

During the whole time the vehicle is travelling the electronic control unit performs a diagnosis cycle every 100 msec. checking the Air Bag system and memorising any faults in the FAULT-MEMORY whether they are momentaneous or continuous. The moment the fault is detected, besides memorising it, the control unit turns on the Air Bag warning light.

When the engine is turned on, this warning light turns on for 4 seconds (initial test) and then it turns off.

If the warning light does NOT turn on or does NOT turn off after 4 seconds it means that there is a fault in the Air Bag system.

The User must then take the vehicle at the soonest to the nearest Service Centre to have the fault repaired because the system is no longer capable of operating correctly.

Once the fault has been signalled, the warning light stays on until the fault has been repaired and cancelled from the fault memory.

DIAGNOSIS USING THE ALFA TESTER

N.B. Before carrying out diagnosis using the tester, carry out the preliminary test described below (TEST A).

To prevent the Air Bags from being triggered accidentally during diagnosis - upon request of the Tester - it is necessary to disconnect them from the wiring and connect a dummy resistance to the connectors which is supplied with the ALFA TESTER cartridge.

1. Driver’s side module R23
2. Passenger’s side module R27

NOTA: When the ignition key is removed, the time and type of fault or error code remain present in the FAULT-MEMORY. Once the fault has been repaired it will be cancelled by the TESTER. Intermittent faults are kept in the FAULT-MEMORY for 48 hours, counted from the time in which they occur (time calculated only with the ignition key at MARCIA).