System functions: Self-test

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

Following start, the Crash Safety Module (ACSM) initiates a self-test. The airbag indicator light in the instrument cluster (KOMBI) remains on during this period (3 to 5 seconds). When the airbag system is ready for operation, the airbag indicator light goes out.

If the instrument cluster (KOMBI) does not receive a CAN message from the Crash Safety Module (ACSM) in this period, the airbag indicator light will light up.

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

If a fault is detected in the airbag system, the airbag system remains partly operable subject to the following conditions:

• If a fault is detected in an airbag system circuit, only the affected circuit 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. Subject to the prerequisite that no other faults are present, the airbag system remains functional without restriction.

In the event of an internal fault or a fault in the voltage supply in the Crash Safety Module (ACSM), the entire airbag system will be disabled (airbag indicator light lights up and a Check Control message is displayed).