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.
Control module
The rear electronic module (REM) handles functions for:
- alarm (certain functions)
- locks (certain functions)
- inclination sensor module (ISM)
- headlamp range adjustment position sensors (Bi-Xenon)
- fuel level (Bi-fuel)
- shut-off valve (Bi-fuel)
- diesel filter preheating (Diesel)
- rear fog lamps
- back-up lamp
- stop lamps
- high level stop lamp
- rear windshield wiper/washers
- rear demist
- rear 12 V socket
- parking assistance system
- electrical connections on the tow hitch
- rear parking lamps/license plate lighting
- rear window lift mechanisms.
The control module is installed as a separate unit in the rear relay box. This is under the left-hand cargo compartment panel.
The rear electronic module (REM) communicates with components which are directly connected and also with other control modules and components via serial communication and the control area network (CAN).
The control module checks activations and input and output signals using an integrated diagnostic system A diagnostic trouble code (DTC) is stored if the control module detects an error. In certain cases the control module replaces the faulty signal with a substitute value.
Any diagnostic trouble codes (DTCs) are stored in the control module memory. This information can be read off using VIDA via the data link connector (DLC) in the vehicle.
Lock and unlock the rear doors to check whether the rear electronic module (REM) is grounded and powered. The control module is powered and grounded if the doors lock and unlock. Another way to check whether the rear electronic module (REM) is powered and grounded is to switch on the rear fog lamp.
For further information, also see the relevant Signal specifications.
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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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