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.
Driver assistance systems operating unit
| Index | Explanation |
|---|---|
| 1 | Function illumination |
| 2 | Button for the warning function of the Adaptive Brake Assistant |
The driver assistance systems operating unit contains a button for switching the collision warning on and off. The operating unit is connected to the footwell module (FRM) on the LIN bus. A bus signal from the FRM notifies the ICM control unit when the button has been pressed.
| Index | Explanation |
|---|---|
| BE_FAS | Driver assistance systems operating unit |
| FRM | Footwell module |
The ICM does not allow the collision warning to switch on unless the entire system is working faultlessly. It is only then that a bus signal providing positive feedback is sent to the FRM in order to have the function illumination in the button light up. If, however, a fault is present in any part of the entire system, the function illumination remains off even if the button is pressed. From this, the driver can infer that the collision warning is not available.
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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.