V50 L5-2.4L VIN 39 B5244S7 (2005)
Steering Mounted Controls Communication Module: Description and Operation
The steering wheel module (SWM) has the task of managing the signals for the steering angle sensor and 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) or using LIN communication.
Steering wheel module (SWM) is available, from and incl. model year 2005 up to and incl. model year 2008, in two different versions. One version with
more and one with less functionality.
Steering wheel module (SWM) with more functionality is installed in vehicles with Dynamic Stability and Traction system (DSTC). From and incl.
model year 2009 there is only Steering wheel module (SWM) with more functionality.
The steering wheel module (SWM) manages signals for the following functions:
steering wheel angle information (only vehicles equipped with DSTC)
steering wheel angle speed for electro-hydraulic power steering
volume control and CD track / radio selection
volume control for hands-free calls and menu selection for Phone module (PHM), which includes starting, ending and receiving calls
volume control for hands-free calls and menu selection for Bluetooth phone module (BPM), which includes starting, ending and receiving calls
menu selection for traffic information (RTI)
windshield washers and wipers
tailgate wiper and washer
turn signal lamps
high and low beam
trip computer and displaying/erasing text messages in the driver information module (DIM)
rain sensor module (RSM)
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.
The Steering wheel module (SWM) communicates with directly connected components (steering wheel buttons) via LIN communication.
The control module also communicates with other control modules via both CAN and LIN communication.
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 a fault. For further information, see: Diagnostic functions See: Diagnostic Functions
The diagnostic trouble code (DTC) is stored when the ignition is switched off.
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.
A simple way to ensure that the steering wheel module (SWM) is powered and grounded is to activate the turn signal lamps or to change the audio or
For further information, also see Signal specifications.
The table below summarizes the input signals to and output signals from the steering wheel module (SWM). The signal types are divided into directly
connected signals, LIN and CAN communication. The illustration below displays the same information with the Volvo component designations.