Replacing Front Wheel Sensor Wiring

Replacing front wheel sensor wiring
The wiring to the front wheel sensor is integrated into the engine compartment wiring. In the past, damage to the wheel sensor wiring has meant replacing all engine compartment wiring. A repair kit for the front wheel sensors is now available as a replacement part.

Note: The earlier repair kit, P/N 9442120-3, should no longer be used

Replacing wheel sensor cable harness
Raise the car and remove the wheel on the side on which the wiring is to be replaced.

Disconnect cable harness from:

- Wheel sensor
- Brackets on spring strut and in wheel arch.
- Clip on brake pipe
- Clip in engine compartment
Pull up the cable harness in the engine compartment.





The new cable harness should be routed in the same way as the old to avoid damage caused by rubbing.





Cut off the old cable harness approximately 20 cm from the cable duct and discard.





The routing and attachment of the cable harness varies with model year and variant. The new cable harness is too long. Cut down as follows. The table contains the cable harness length in mm. "Left" and "Right" in the table refer to the cable harness for the left or right sensor.

Strip cable harnesses





Strip the new cable harness and strip the cut cable harnesses in the car.
Use cable stripping tool 951 2641-3.

Strip insulation





Strip 25 mm of the outer insulation on the existing cable harness, and 65 mm on the new cable harness.
Open the cable stripping tool and position it where the insulation is to be cut.
Twist the tool round a few times in the max direction to score the insulation.
Turning the tool in the Max direction cuts into the insulation deeper than turning it in the Min direction.





Bend the cable several times at the score. Pull off the insulation.
Check that the stripped sections are 65 and 25 mm respectively.





Thread the larger piece of heat-shrink tubing onto the new cable harness.





Cut off the two smaller pieces of heat-shrink tubing to 30 mm long.
Thread them onto the 65 mm long, stripped cables.

Strip cable pairs





Strip insulation on the 4 cable ends 13 mm with pliers 951 2620.

Twist cable ends





There may be a thin plastic film residue on the white (tinned) conductor units.
Untwist the stripped cable ends a little and twist them together again. For safety reasons, do the same with all four stripped cable ends.

Splice the same colored cable ends





Position a crimping sleeve in the crimping tool 951 2649, in crimping slot "A" (This is easier on a workbench).
Squeeze the crimping tool a little to secure the crimping sleeve in the tool.

Install crimping sleeve





Place both cable ends (same color) in the crimping sleeve in the crimping tool. Insert cables in crimping sleeve so that their insulation comes up to but not into the crimping sleeve. Both cables should be inserted from the same direction (parallel).

Note: Insert cables in the crimping tool on the side without text!

Press crimping sleeve tight.
Check by hand that crimping sleeve is secure.

Splice the cable pairs








When the cable ends are together solder the tops of the conductor units outside the crimping sleeve. This work may only be performed by a professional, accustomed to soldering electric components.
Set up an extractor by the soldering site.
Take care of adjacent cables. If necessary set up a heat shield.
Heat the crimping sleeve/conducting unit ends with the soldering iron. Heat thoroughly. Apply solder so that some runs into the crimping sleeve covering the conducting units.

Install a section of heat-shrink tubing onto the cable splice





Fold both cable splices as illustrated (arrow).
Carefully pull the heat-shrink tubing over the soldered cable splices.

Heat the heat-shrink tubing





The heat-shrink tubing is intended to provide good electrical insulation.
Hold a putty knife behind the heat-shrink tubing and heat at close range using a hot air gun. Heat the heat-shrink tubing quickly to avoid heating up the area around the site.
It is important to fully shrink the heat-shrink tubing around the crimping sleeve. The ends should be sealed.
If necessary set up a heat deflector.
Twist cables as much as possible before pulling the large heat-shrink tubing over the heated and heat-shrink covered cable splices.





Pull the heat-shrink tubing over the cable splices.





Heat with a hot air gun to seal the heat-shrink tubing at both ends.
The new, spliced cable harness should be routed down to the wheel sensor in the same way as the old to avoid damage caused by rubbing Secure the new cable harness in the same way as the old one.
Reinstall wheel.
Tighten wheel nuts alternately to 110 Nm.

Checking ABS system





After repairs are complete it is important to check the ABS system.
- Ignition off.
- Connect adapter 951 1354 to control module connector on wiring side (see illustration)
- Connect breakout box. 981 3190 to adapter.
- Control module disconnected.





- Take readings described in the table