System self-test

The control unit carries out a continuous self-test of the system's operation. In particular:

it detects and memorizes any faults

it recognizes the various components and the type of fault

it signals the onset of these faults via the special warning light in the instrument panel:

if a fault is detected with the manual disabling switch, it is considered in the OFF state and therefore the operation of the passenger Air Bag is inhibited.

if a fault is detected in the automatic disabling sensor, then the command is sent to the modules according to the normal operation.

The faults stored in the control unit memory can be cancelled, after the fault has been repaired, using the Examiner or other diagnostic equipment.

System activations following a particularly serious impact are memorized by the control unit.

In the case of an impact which has caused the complete system to be activated (Air Bag and pretensioners) it is not possible to cancel the control unit memory and it must therefore always be replaced.

If, on the other hand, only the pretensioners are activated, the memory can be cancelled twice. The control unit only has to be replaced if it is activated a third time.