Replacing an ABS sensor

Typically the first you will know of an ABS fault is when your wheels lock under braking and your tyres screech to a halt. The orange light on the dash that signifies the ABS system is not active is also a dead giveaway.

Diagnosing which ABS sensor is at fault

The first issue is how to tell which of the ABS sensors has failed. To diagnose which ABS sensor is at fault you need a multimeter and the diagrams below. The pictures show the ABS unit plug for a MK1 and MK2 106. Check the alignment of your gold pins to see which one applies to your car:

MK1 106 ABS Plug

MK1 106 ABS Plug

MK2 106 ABS Plug

MK2 106 ABS Plug

1) Open the bonnet and remove the air filter housing.

2) Look under the battery and carefully wiggle the large red clip outward while pulling on the loom plug gently. Eventually the red clip will retract and you can pull the plug free.

3) Using the diagram below and your multimeter set to resistance, test each of the two pins in order to see if any return a resistance of 1.

4) The 3 working ABS sensor should offer a resistance of zero so you will be able to isolate which is the problem.

 

Replacing a front ABS sensor.

This is much easier than the rear sensor.

1) Loosen the wheel and jack the car up and safely secure on Axle stands. Do not work under the car without them.

2) Remove the wheel

3)  Reach underneath and trace the ABS sensor wire back behind the chassis leg. There is a cover with two small lugs you can undo with your fingers revealing the blue loom plug. Squeeze the clip on the loom and pull the blue plug free.

4) Double check the sensor is dead by putting your multimeter pins on the ABS loom plug pins. The resistance should be 1.

5) Now you are left with the ABS sensor secured into the hub. Luckily Peugeot have been sensible for once, and made it easy to remove the sensor in situe as it is secured to a small metal bracket behind the brake disc. Turn the steering wheel to gain easier access. Undo the 10mm nut, plastic sensor cover, and the two 13mm and 10mm bolts respectively. You should then be able to remove the bracket from the hub with the sensor in situe.

6) To remove the old broken sensor from the hub, you’ll probably need to use some WD40 and brute force. Secure the bracket in a vice and find your best hammer. Using a drift or similar, hammer the sensor free of the bracket. Eventually after some time it will come free.

7) Clean the bracket with a wire brush or dremel tool then add a little grease. Fit the new sensor in it’s place – it may need a few gentle taps to secure.

8) In true Haynes Manual style refitting is then the reverse of removal, remembering to secure your wheel bolts and check tightness after 50 road miles.

 

 

 

 

 

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