Description of On-Board Diagnostics

Airbag System With Side Airbags, On Board Diagnostic (OBD)

General notes

The airbag system is comprised of the driver's airbag, front passenger's airbag, two front seat belt tensioners and two side airbags at the front. In a crash situation, these are activated centrally by the Airbag Control Module -J234- when the specified triggering threshold is exceeded.

It is possible to disable and enable the front passenger-side airbag using the key-operated switch.

If an airbag and/or belt tensioner is triggered, the control module will record the DTC "Crash data stored."

The Airbag Control Module -J234- must be replaced:

- If the driver's or front passenger's airbag has been triggered once.
- If the front belt tensioners and/or side airbags have been triggered three times.

If a new control module is installed it must be coded.

Whatever the nature of the accident and however serious the impact, the Airbag Control Module sends a "crash signal" to the control module for the central locking system. This function is a passive safety feature designed to release the door locks and tailgate lock via the central locking system if an airbag is triggered. In addition, the internal central locking switch is disabled and the interior lights are switched on. The "crash signal" can be checked using the output diagnostic test mode.

The control module detects malfunctions in the airbag system and stores them in a permanent memory.

When the ignition is switched on, the airbag Airbag Malfunction Indicator Lamp (MIL) -K75- lights up for about 4 seconds and then goes out again. If the lamp then flashes for a further 12 seconds, this indicates that the front passenger's airbag has been deactivated (disabled).

- If the Airbag Malfunction Indicator Lamp (MIL) - K75- does not go out after about 4 seconds, this means that there is a malfunction in the voltage supply for the Airbag Control Module - J234- Check DTC memory.
- If the Airbag Malfunction Indicator Lamp (MIL) - K75- goes out and comes on again, this indicates either that the control module has not been coded, or that the wrong control module has been installed, or that a malfunction has occurred. Check DTC memory.

WARNING:
- Wiring must only be checked by visual inspection.
- Never use electrical tests to check or measure continuity in the igniter circuits.
- Always switch ignition off before inspecting wiring.