Calibrating Steering Angle Sensor
Important notes
A steering angle sensor (arrow) is attached to the steering column/steering shaft in the 911 Carrera (996) with PSM (Porsche Stability Management). PSM is standard in the 911 Carrera 4 (996).
The steering angle sensor (arrow) supplies information about the slip angle of the front wheels to the PSM control unit (intention of driver in relation to direction of travel).
Steering angle sensor position
The angle steering sensor has no defined zero position when new. The position for "straight ahead" direction of travel must be programmed. This is done by calibrating with the Porsche System Tester 2 with the wheels in straight-ahead position.
Important: Malfunctions in the PSM control range if the steering angle sensor is not calibrated or is calibrated incorrectly.
The steering angle sensor must be calibrated after:
- A new steering angle sensor has been installed.
- The PSM control device has been exchanged.
- The steering gear and / or components which change the zero position of the steering angle sensor have been exchanged.
- Accident repairs
- Suspension alignment procedures during which the previous wheel alignment values were changed.
The steering angle sensor actual value must be checked:
- After a suspension alignment which resulted in no changes being made to the wheel alignment values.
- As a check after steering angle sensor calibration.
Checking the steering angle sensor actual value
- Connect the Porsche System Tester 2 to the diagnostic socket (arrow).
- Select vehicle type and then enter PSM system. Entry takes place through the ABS system (automatic status change after PSM).
- Select steering angle sensor in the Actual values menu.
- Required display in the Tester display with wheels in straight-ahead position 00 ± 30.
- If the steering angle sensor actual value deviates or is doubtful, recalibrate the steering angle sensor on the measuring platform.
Calibrating steering angle sensor
See text for information on when calibration is to be carried out.
Important: Malfunctions in the PSM control range if the steering angle sensor is not calibrated or is calibrated incorrectly.
- Calibrate steering angle sensor with wheels in straight-ahead position on measuring platform.
- Check the steering angle sensor actual value with wheels in straight-ahead position before calibrating the steering angle sensor! Only recalibrate the steering angle sensor on the measuring platform if the steering angle actual value lies outside the tolerance or is doubtful.
- Drive vehicle onto measuring platform. Affix measured-value pickups to all wheels. Check wheel alignment values and adjust if necessary. If the wheel alignment values on the front and rear axles are correct, calibrate the steering angle sensor with the front wheels in straight-ahead position.
- Calibration description in following text.
- Select the "Calibrate steering angle sensor" menu with the Porsche System Tester 2 in the PSM system. Entry to the PSM system takes place through the ABS system (automatic status change after PSM).
- Confirm calibration start. The procedure can also be interrupted.
- Ensure that the wheels of the vehicle are in straight-ahead position.
- Then proceed (continue).
- The PST 2 now requests the 4 digit safety code.
Note: This safety code must be retrieved in the Actual values menu, Safety code submenu. This safety code changes automatically each time provided that PSM is called up again.
- Enter the 4 digit safety code with the cursor keys (4 keys center right). Then proceed with the Next key
- Confirm safety code input.
Important: The final possibility to interrupt the calibration is not to confirm the safety code input. To do this, press the appropriate function key for no.
Display in the Tester display after the safety code input has been confirmed: Steering angle sensor is being calibrated.
Note: The calibration procedure will be interrupted if an incorrect safety code is entered. This time-consuming procedure ensures that the steering angle sensor is not calibrated unintentionally.
- For safety reasons, read out the current steering angle sensor actual value after calibration. To do this, leave the PSM system. Then call up PSM again and select the steering angle sensor in the Actual values menu. Required display in the Tester display: 00 ± 30 when the wheels are in straight ahead position.
- Repeat the calibration if the value is not correct.
Note: The steering angle sensor can be calibrated several times. The value (the zero position) is stored in the steering angle sensor itself.