Steering Angle Sensor: Service and Repair
Removing And Installing Steering Angle Sensor
- A steering angle sensor -C- is attached to the steering column/steering shaft in the 911 Carrera and 911 Carrera 4 with PSM (Porsche Stability Management).
- The cover -D- remains fitted during removal and installation of the steering angle sensor. In general the removal of the cover -D- is not authorized.
A - Universal joint of steering shaft
C - Steering-angle sensor. From amended version of 2003 model.
D - Cover
Important Note On Steering Wheel Position For Removal And Installation
- Lock the steering wheel and the front wheels in straight-ahead position. Make sure that this position is retained for reinstallation. Refit in the same position during installation.
- If this is not done, the airbag contact unit (spiral spring) can be damaged. Also, the steering wheel can be crooked with the front wheels in straight-ahead position after installation of the steering angle sensor.
Removal
1. Remove driver's seat.
2. Switch ignition off.
3. Remove air guide channel.
4. Turn front wheels to straight-ahead position. Affix the front wheels and the steering wheel in this position.
5. Undo hexagon-head bolt on universal joint -A-. Detach universal joint -A- from the upper steering shaft and push into the lower steering shaft (-direction arrow-). Disengage cable guide -B- in the direction of travel.
A - Universal joint of steering shaft
B - Cable guide
C - Steering-angle sensor
D - Cover
NOTE: Pull at the plug housing only. Never pull the electrical connections.
6. Pull oft steering angle sensor plug. The connector should be removed sideways -direction arrow- or forwards (depending on the steering angle sensor model). Disengage the steering angle sensor -C- forwards. To do this, press the sensor carefully through the opening in the cover -D- (-direction arrow-).
Note On The Replacement Of The Steering Angle Sensor - Vehicles Before Mod. 03
A new steering angle sensor -C2- will be installed from the 2003 model onwards (3 programmes). This intrinsically modified steering angle sensor -C2- differs (externally) from the previous steering angle sensor -C1- by its larger plug connection which is positioned differently. New steering angle sensor -C2-: axial plug connection (underneath steering shaft)/previous steering angle sensor -C1-: radial (lateral) plug connection.
- In the case of replacements, the new steering angle sensor -C2- can be installed retroactively in place of the previous model -C1-.
- When installing the new steering angle sensor -C2- for the first time in vehicles prior to the 2003 model, a new cable guide -B2- must be installed (in place of the old one) together with an adapter lead -E- because of the modified plug connection (larger connector, connector position and modified connector assignment).
- The main difference between the old cable guide -B1- and the new one -B2- (series installation after 2003 models the cable deflection on its end. The cable shaft (ribs) of the new cable guide -B2- are interrupted in places to install the guide (ribs in old cable guide -B1- are not interrupted).
- The adapter lead -E- is installed (assembled) between the new steering angle sensor -C2- and the available (previous) lead -X-. The connected leads -X and E- are then installed with the plug connection in the cable shaft of the new cable guide -B2- and fixed with the tie-wrap -arrow-.
NOTE: Fold the fines -E and X- before installing in the cable shaft so that the lines are correctly positioned on top of each other.
- Component Survey
PIN assignment of the adapter lead -E-
Installation
CAUTION:
No airbag function if the spiral spring on the airbag contact unit is damaged. Observe mounting specifications.
- Avoid uncontrolled movements of the steering wheel to the wheel position (by turning the steering wheel when the cardan joint on the steering wheel is disassembled). This includes: If the assembly steering wheel is turned by the steering angle sensor, the steering wheel and the spiral spring in the airbag contact unit must be replaced in the same position before the cardan joint is assembled.
- Before assembling the cardan joint on the upper steering shaft, the front wheels, the steering wheel and the airbag contact unit must be correctly positioned in relation to one another. This means that they should be in the same position in relation to one another as they were before removal (central position of steering wheel and spiral spring and straight-ahead position of the wheels).
NOTE:
- The steering angle sensor and the auxiliary adapter on the steering angle sensor must lock with an audible click.
- Use new fastening screws on the cardan joint. Observe tightening torque of the screw.
- When replacing steering angle sensors in vehicles prior to the 2003 model, make sure that the components are allocated correctly in the surroundings (dependent on the steering angle sensor model).
- The steering angle sensor has no defined zero position when new. The position for "straight ahead" direction of travel must be programmed. This is done by calibration with the Porsche System Tester with the wheels in the straight-ahead position at the measuring station.
1. Attach the steering angle sensor 'in 2 steps' to the steering column (steering shaft). '1st step: Attach' adapter -1- to the steering shaft (engage). '2nd step:' Attach steering angle sensor to adapter -1- (detailed instructions are provided in the text below).
1 - Auxiliary adapter
2 - Steering angle sensor driver
3 - Inner lug (to attach to the upper steering shaft)
4 - Outer lug
5 - Lock (notch) to driver
Detailed instructions:
- First of all disengage auxiliary adapter -1- from the driver -2- of the steering angle sensor -lock 5- and remove.
- Push the auxiliary adapter -1- onto the steering shaft. The lugs -3 and 4- must be pointing towards the steering wheel. The inner lug -3- must engage fully in the steering shaft cutout -6-. Carry out tightness test: The auxiliary adapter -1- must not be allowed to pivot on the steering shaft. To ensure that the cutout in the steering shaft -6- is visible in the opening of the cover -D-, move the steering wheel beforehand out of the original position as required. Then move the steering wheel back into the original position.
- Push the steering angle sensor -C- over the installed auxiliary adapter. The steering angle sensor driver -2- is pointing in the direction of the steering column. The outer lug -4- on the auxiliary adapter must engage fully in the driver lock. To ensure that the lug -4- is visible in the opening of the cover -D-, move the steering wheel beforehand out of the original position as required. Then move the steering wheel back into the original position.
NOTE: If the steering wheel was not fixed before removing the steering angle sensor or the steering wheel was turned before installing the steering angle sensor on the steering shaft, the contact unit (spiral spring) may no longer be in the correct position. In this event, remove steering wheel and move contact unit to centre position.
2. Attach steering shaft (cardan joint) -A- in the correct position - same position as before removal (straight-ahead position of the wheels, centre position of the steering wheel and spiral spring) - to the upper steering shaft.
3. Attach connector to the steering angle sensor (attach cable) and engage cable guide -B-. 'Only install the new cable guide with the adapter lead (text below) when using the modified steering angle sensor - version C2 - for the first time in vehicles before the 2003 model'.
Conversion - new steering angle sensor in vehicles before 2003 model
When converting from the old to the new steering angle sensor model -C2- the new cable guide -B2- with an adapter lead -E- (large connector on steering angle sensor) must be installed in place of the old cable guide and the previous lead (small connector on steering angle sensor). To do this:
- Assemble new cable lead -B2- (engage on the steering column) and install the adapter lead -E-.
- Attach the large connector on the adapter lead -E- to the new steering angle sensor -C2- (engage).
- Link up the connector on the available lead -X- with the connector on the adapter lead -E-.
- Install available lead -X- and the adapter lead -E- together with the plug connection in the cable shaft and fix in place with a thin tie-wrap -arrow-. Fold the lines before installing in the cable shaft so that the lines are correctly positioned on top of each other.
4. Install air guide channel.
CAUTION:
Malfunctions in the PSM control range if the steering angle sensor is not calibrated or is calibrated incorrectly.
- The steering angle sensor has no defined zero position when new. The position for "straight ahead" direction of travel must be programmed.
- Calibrate steering angle sensor with the Porsche System Tester with the wheels in the straight-ahead position at the measuring station.
5. Calibrate steering angle sensor.