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 Boxster and Boxster S with PSM (Porsche Stability Management).
- The cover -D- remains fitted during removal and installation of the steering angle sensor. In general, removal of cover -D- is not permissible.
A - Universal joint of steering shaft
C - Steering-angle sensor. As of model 2003 modified versions
E - Cover
Instructions On Steering Wheel Position For Removal And Installation
- Lock steering wheel and front wheels in straight-ahead position. Make sure that this position is retained for reinstallation. Refit in same position during installation.
- If this is not done, the airbag contact unit (spiral spring) can be damaged. Also, the steering wheel can be misaligned with the front wheels in straight-ahead position after installation of the steering angle sensor.
Removal
1. Remove driver's seat with the convertible top open (to facilitate work).
2. Switch ignition off.
3. Remove air duct.
4. Turn front wheels to straight-ahead position. Fix 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 direction of travel.
A - Universal joint of steering shaft
B - Cable guide
C - Steering-angle sensor
E - Cover
NOTE: Pull at the plug housing only. Never pull the electrical connections.
6. Pull off steering angle sensor plug. The plug is pulled off to the side -direction arrow- or to the front (depending on the steering angle sensor version). Disengage steering angle sensor -C- forwards. To do this, press the sensor carefully (-direction arrow-) through the opening in the cover -D-.
Instructions On Replacing Steering Angle Sensor - Vehicles Before Mod. '03
As from model 2003 (3 range) there is a new steering angle sensor -C2- installed. This internally modified steering angle sensor -C2- is distinguished (externally) from previous steering angle sensors -C1- by the plug connection being larger and in a different position. New steering angle sensor -C2-: axial plug connection (below steering shaft); previous steering angle sensor -C1-: radial (side-mounted) plug connection.
- In the event of replacement, the new steering angle sensor -C2- can be installed retroactively instead of the previous version -C1-.
- When installing the new steering angle sensor -C2- for the first time in vehicles before model 2003, because of the modified plug connection (larger plug, position of plug and modified pin assignment), a new cable guide -B2- (instead of the old cable guide) together with an adapter lead -E- must be fitted.
- The old cable guide -B1- is distinguished from the new cable guide -B2- (series implementation as of 2003 model) mainly by the cable rerouting at the end. The cable duct (ribs) of the new cable guide -B2- are for laying the lead in sections (ribs in old cable guide -B1- are uninterrupted).
- The adapter lead -E- is inserted between the new steering angle sensor -C2- and the existing (previous) lead -X-. Next the joined leads -X and E- together with the plug connection are inserted in the cable duct of the new cable guide -B2- and fixed with a tie-wrap -arrow-.
NOTE: Before insertion in the cable duct, the leads -E and X- are folded so that they lie one above the other and are positioned neatly.
Overview Of Components
PIN assignment of adapter lead -E-
Installation
CAUTION:
The airbag will not function if the spiral spring of the airbag contact unit is damaged. Observe installation instructions.
- Avoid uncontrolled turning of the steering wheel at the wheel position (by turning the steering wheel when the universal joint is disassembled from the steering shaft). This means: If the steering wheel is turned to install the steering angle sensor, then the same position of the steering wheel, and hence of the spiral spring in the air-bag contact unit, must be reproduced before fitting the universal joint.
- Before fitting the universal joint to the upper steering shaft, the front wheels, steering wheel and airbag contact unit must be positioned correctly relative to each other. This means in the same relative position as before removal (steering wheel and spiral spring in mid-position and wheels in straight-ahead position).
NOTE:
- The steering angle sensor and the hub adapter of the steering angle sensor must audibly engage.
- Use new fastening screw on universal joint. Observe tightening torque of screw.
- When replacing steering angle sensor in vehicles before model year 2003, observe the correct allocation of components in the surrounding area (depends on steering angle sensor version).
- 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 calibrating with the Porsche System Tester with the wheels in straight-ahead position on the measuring station.
1. Mount steering angle sensor 'in two steps' on the steering column (steering shaft). 'Step 1:' Fasten adapter -1- to the steering shaft (snap in). 'Step 2:' Mount steering angle sensor on adapter -1- (detailed instruction follow below).
1 - Hub adapter
2 - Steering angle sensor driver
3 - Inner lug (fastener to upper steering shaft)
4 - Outer lug
5 - Detent (cut-out) on driver
Detailed instructions:
- First disengage hub adapter -1- from driver -2- of steering angle sensor (-detent 5-) and pull out.
- Push hub adapter -1- onto steering shaft. Lugs -3 and 4- must point towards the steering wheel. Inner lug -3- must engage fully in the cut-out of steering shaft -6-. Check for secure fit as follows: Hub adapter -1- must not turn on the steering shaft. So that the cut-out in steering shaft -6- will be visible in the opening of cover -D-, first turn the steering wheel from the initial position as required. Then return the steering wheel to the the initial position.
- Push the steering angle sensor -C- over the hub adapter already fitted. The driver of the steering angle sensor -2- points towards the steering column. Outer lug -4- of hub adapter must engage fully in detent of the driver. So that the lug -4- will be visible in the opening of cover -D-, turn the steering wheel from the initial position as required. Then return the steering wheel to the the initial position.
NOTE: If the steering wheel was not fixed before the steering angle sensor was removed or the steering wheel has been turned during fitting of the steering angle sensor to the steering shaft, the position of the contact unit (spiral spring) may no longer be correct. In this event, remove steering wheel and move contact unit to mid-position,
2. Fasten steering shaft (universal joint) -A- in the correct position on the upper steering shaft - same position as before removal (wheels in the straight ahead position, steering wheel and spiral spring in mid-position).
3. Push plug onto steering angle sensor (connect cable) and engage cable guide -B-. Install new cable guide with adapter lead (see figure) 'only if the modified steering angle sensor (version C2) is being fitted for the first time in vehicles before model year 2003'.
Conversion - new steering angle sensor in vehicles before model year 2003
For conversion of the old to the new steering angle sensor version -C2-, instead of the old cable guide and the previous lead (small plug on steering angle sensor), the new cable guide -B2- with adapter lead -E- (large plug on steering angle sensor) must be installed. To do this:
- Fit new cable guide -B2- (snap onto steering column) and insert adapter lead -E-.
- Push large plug of adapter lead -E- onto new steering angle sensor -C2- (snap on).
- Connect the plug of the existing lead -X- to the connector of the adapter lead -E-.
- Insert existing lead -X- and adapter lead -E- together with plug connection into cable duct and fix with a thin tie-wrap -arrow-. Before inserting leads in the cable duct, fold them so that they lie one above the other and are positioned neatly.
4. Install air duct.
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 wheels in straight ahead position on the measuring station with the Porsche System Tester.
5. Calibrate steering angle sensors.