Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
System Functions: Notes
The function of the ACSM is to permanently evaluate all sensor signals in order to detect a crash situation. As a result of the sensor signals and their evaluation, the Crash Safety Module identifies the direction of the crash and the severity of the impact.
Also included is information on the occupants and whether they have their seat belts fastened or not. From this information, measures are taken to selectively trigger the necessary restraint systems.
The crash safety module monitors the system itself and indicates that the system is ready for operation when the airbag warning lamp (AWL) goes out.
If a fault occurs during operation, this is stored in a fault memory, which can then be read out for diagnostic purposes.
If a crash situation is detected, this is communicated to the other users in the bus-system network by way of a bus signal. The relevant control units respond to this signal by executing their own activities according to the severity of the crash.
The activities include:
- Opening the central-locking system
- Activating the hazard warning flashers
- Switching on the interior lighting
- Deactivating the fuel pump
- Switching off the auxiliary heating
- Automatic emergency call.
A function of ACSM is the seat belt reminder function, which uses optical and acoustic signals to remind the driver and front passenger to fasten their seat belts.
The functions of the ACSM are divided into:
- Crash-relevant functions
- System monitoring functions
- Additional comfort functions.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.