Crash safety: Self-test

In addition to all the inputs and outputs, the Crash Safety Module (ACSM) also monitors the internal construction components (self test). Possible fault codes are stored in the Crash Safety Module. In the event of a system error or a fault in a component, the airbag warning lamp lights up.

The Crash Safety Module performs a self test after the ignition is switched on. The airbag indicator lamp in the instrument cluster remains on during this period (of roughly 3 to 5 seconds). The airbag indicator lamp goes out as soon as the safety system is ready for operation.

If the instrument cluster fails to receive a CAN message from the Crash Safety Module in this period the airbag indicator lamp will light up.

The airbag indicator light remains on if the Crash Safety Module detects an existing fault or one that has been stored during the self-test or while driving.

If a fault is detected in the safety system, the operability of the safety system is partially maintained under the following conditions:

• If a fault is detected in a circuit of the safety system, only the function of the circuit concerned is disabled. The other airbag and seatbelt tensioners remain functional.
• In the event of a fault in the circuit of the airbag warning lamp, the lamp does not light up in the self-test. With the precondition that no other fault is present, the safety system remains functional without restriction.

In the event of an internal malfunction or a fault in the power supply in the Crash Safety Module, the entire safety system will be disabled (airbag indicator and seat belt warning lamps light up, Check Control message in the instrument cluster).