XC90 2.5T AWD L5-2.5L Turbo VIN 59 B5254T2 (2003)
Steering Mounted Controls Communication Module: Description and Operation
The steering wheel module (SWM) has the task of managing the signals for those functions which can be controlled via the steering wheel control stalks
and buttons. The signals are transmitted to the relevant control modules via the control area network (CAN). The actual functions are not in the steering
wheel module (SWM).
The steering wheel module (SWM) manages the control signals for the following functions:
Volume control and CD track / radio selection
Volume control during hands free carphone calls and menu selection for the phone module (PHM)
Menu selection for traffic information
Front windshield wipers/washers
Rear windshield wiper/washer (V70, V70XC/XC70 and XC90)
Turn signal lamps
High and low beam
Trip computer and displaying / erasing text messages in the driver information module (DIM).
The control module is integrated in the steering wheel bracket. The steering wheel must be removed to replace the control module. Control stalks, key
pads and switches can be replaced as separate units.
Cars with DSTC also have a steering wheel angle sensor installed in the contact reel in the steering wheel module (SWM). For further information, see
Design and Function, Steering Wheel Angle Sensor Module (SAS).
The steering wheel module (SWM) communicates with directly connected components and communicates with other control modules via the Control
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 control module replaces the faulty signal with a substitute signal.
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.
A simple way to ensure that the steering wheel module (SWM) is powered and grounded is to flash the headlamp high beam or to change the audio or
For further information, also see Signal specifications.