System Overview

System overview

Control module




The primary task of the upper electronic module (UEM) is to manage the functions of the:
- Siren control module (SCM)
- Sun roof
- Mass movement sensor module (MMS)
- Rain sensor module (RSM)
- Interior roof lighting
- Cargo compartment lighting (V70 and XC70)
- Sun visor lighting
- Remote control
- Automatic rear view mirror anti-dazzle
- Seat belt reminder
- Tire pressure warning
- Indication of disconnected passenger airbag (PAD- Passenger Airbag Deactivated)
- Compass
The control module is integrated in the rear view mirror. If the control module is replaced, the rear view mirror assembly must also be replaced.
The upper electronic module (UEM) communicates with directly connected components and with other control modules and components via serial communication and the controller area network (CAN).
The control module checks activations and input and output signals via an integrated diagnostic system. A diagnostic trouble code (DTC) is stored if the control module detects an error. In certain cases the upper electronic module (UEM) replaces the faulty signal with a substitute value.
Any diagnostic trouble codes (DTCs) are stored in the control module memory. The data can be read off using VIDA.
A simple way to check that the upper electronic module (UEM) is supplied with power is to activate the seat belt reminder function. Activate the seat belt reminder by sitting in the driver's seat. Switch on the ignition, do not fasten the seat belt. If the seat belt reminder lights, the upper electronic module (UEM) is supplied with voltage. Another way of checking that the control module is supplied with voltage is to switch on one of the rear reading lamps.
For further information, also see Signal specifications.

Signals
The table below summarizes the input signals to and output signals from the upper electronic module (UEM). The signal types are divided into directly connected signals, serial communication and controller area network (CAN) communication. The illustration below displays the same information with the Volvo component designations.