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.
Audio Module (AUM) (2001-2007): Function
The audio module (AUM) functions as a sound unit in the car and is also connected to other control modules on the Controller area network (CAN). The audio module (AUM) receives the vehicle speed signal via the Control area network (CAN). Volume increases with speed (if the function is selected; the function can be switched off).
If a factory-installed carphone (option) is installed, the audio module (AUM) is muted during telephone calls.
If an accessory electronic module (AEM) is installed, the audio module (AUM) is muted if either a handsfree telephone is used (accessory) or back-up gear is selected if the car has a back-up warning system (accessory).
If the car has the Road Traffic Information system (RTI) (option), voice information is played back through the existing loudspeaker.
The keypad for remote operation (option) on the steering wheel is directly connected to the steering wheel module (SWM) via serial communication. The remote control keypad is on the right-hand side of the steering wheel. It is possible to control the volume (increase-decrease) and change the preprogrammed radio stations via remote operation. The buttons are used to select a track when playing a CD, cassette or Mini-Disk.
The steering wheel module (SWM) communicates with the audio module (AUM) via the Controller area network (CAN).
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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.
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