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.
Rear fog lamp
The rear fog lamps (10/46, 10/53) are activated by pressing the button for the rear fog lamps in the lamp switch module (3/111). The light switch module (LSM) transmits a request to light the lamps to the central electronic module (CEM) (4/56) using serial communication. The central electronic module (CEM) transmits the request to the rear electronic module (REM) (4/58) via the Controller area network (CAN). The rear electronic module (REM) activates the relay (2/49) and the lamps are supplied with power via the relay.
Central Electronic Module (CEM) transmits information:
- back to the light switch module (LSM) to light the LED in the button
- via the Controller area network (CAN) to the driver information module (DIM) (5/1) to light the indicator lamp for the rear fog lamps.
Information about the lamp circuit is obtained by the rear electronic module (REM) via a shunt (20/29). The rear electronic module (REM) sends the status of the lamp fault via the Control area network (CAN) to the central electronic module (CEM). In the event of a fault, the central electronic module (CEM) transmits data via the Control area network (CAN) to the driver information module (DIM) which displays a text message.
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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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