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
• fuel level (Bi-fuel)
• shut-off valve (Bi-fuel)
• rear fog lamps
• back-up lamp
• stop lamps
• high level stop lamps
• rear windshield wiper/washers
• rear demist
• cargo compartment lighting
• rear 12 V socket
• parking assistance (applies only to the XC90 2003-2004).

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 car.

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.