Steering Wheel Angle Sensor
The steering wheel angle sensor is incorporated with the SRS contact reel, which in turn is installed on the steering wheel module (SWM). A code wheel is mounted inside the steering wheel angle sensor which follows the movements of the steering wheel. 9 optical digital sensors and 2 analog photo diodes read off the code wheel. The signal must create a specific pattern. This information is transmitted to the steering wheel angle sensor module (SAS) which uses these signals to calculate the steering wheel angle, speed and number of turns. In total, the steering wheel angle sensor can measure a range of +/- 720 degrees, although the steering wheel can only be turned a maximum of +/-540 degrees.
Due to the reliance of the DSTC (Dynamic stability and traction control) system on information from the steering angle sensor it is extremely important that the contact reel has been centered correctly and that only an original Volvo steering wheel is used.