Design

Design

Steering wheel angle sensor




Steering wheel angle sensor is integrated in the SRS-contact reel, which in turn is integrated in the Steering wheel module (SWM).
For Steering wheel module (SWM) with more functionality the steering wheel angle sensor, up to and incl. model year 2007, features a disc with code groove.
A circuit with light-emitting diodes read off the code groove and measures the steering wheel angle during one revolution. The steering wheel angle sensor also measures the current number of steering wheel revolutions using an analogue magnet-resistive sensor. By comparing the different sensors' signals, the control module can decide the exact steering wheel angle. Diagnostic trouble code is generated at ± 2.0 revolutions.
From and incl model year 2008 the disc with code groove was replaced with another analogue magnet-resistive sensor. However, the comparison between sensors takes place in a similar way.
The steering wheel angle sensor gives the Brake control module (BCM) information about the steering wheel speed among other things. Information about the steering wheel speed is also used by the Electrical power steering module (EPS).
Steering wheel module (SWM) with less functionality is only equipped with the analog magnet-resistive sensor that provides the Electrical power steering module (EPS) with information about the steering wheel angle speed.
The Electrical power steering module (EPS) uses the information about the steering wheel angle speed to provide the correct pump pressure for the steering function. As a result, the steering wheel module (SWM) is critical to safety.
It is important that the steering wheel angle sensor is correctly installed and that only Volvo original steering wheels are used.
When replacing the steering wheel, the instructions supplied must be followed to ensure that the 0 position of the steering wheel angle sensor is correctly calibrated.

Steering wheel buttons




The steering wheel buttons control functions and menu selection for:
- traffic information (RTI) (option)
- audio (option)
- carphone (option)
- bluetooth (option)
- cruise control (option).
The signals from the steering wheel switch left (SWSL) and steering wheel switch right (SWSR) is transmitted via LIN communication.
The steering wheel buttons are connected to the steering wheel module (SWM) via contact reel in the steering wheel hub.
There are diagnostics for the steering wheel buttons.

Steering wheel control stalks




The steering wheel control stalks are directly connected to the steering wheel module (SWM).
The right-hand control stalk controls the following functions:
- windshield and tailgate wipers (5 door only)
- windshield, rear windshield and headlamp washers
- intermittent wiping
- rain sensor.
The left-hand control stalk controls the following functions:
- turn signal lamps
- high beam
- headlamp flash
- trip computer/timer start for the parking heater.
There are diagnostics for the functions of the steering wheel control stalks.