Sunday, 18 June 2017

Fixing an ABS sensor warning

Yet again the dashboard warning lights were on that are comically referred to as the 'three amigos.'

There was also a forth general brake warning light on. The three amber 'amigo' lights, traction control, ride height and ABS, only indicate something wrong with the ABS system but not exactly where the fault is.


The trusty Nanocom to the rescue again. It pointed clearly to the rear left sensor.


Looking under the car it was a very easy diagnosis. The sensor cable had been rubbing against the wheel rim and worn through the cables!

I had a quick look on the Internet about how to replaced the sensor but according to a workshop service release from Land Rover in 2001, the sensor is deliberately supplied pre-installed in the hub because workshops are not usually clean enough to fit the sensor without getting grub inside which would affect the operation!

The sensors are therefore usually only available with a hub.

I will eventually have the hub replaced but for the time being I have done a pretty robust repair of the broken wires.





With the wheel off it was very easy to access the wire.


I've trimmed back the insulation and joined the wires. I made a splint out of a small spade connector. I could have soldered them but I am very reluctant to solder any wires on a vehicle.


I was taught that solder stops the strands in wires from flexing so the cable has a tendency to break at the margin between the solder and the free strands. As I've seen this myself, many times, I have no doubt.

I invariably use a crimp joint unless it is really not practical.



I wrapped the joint in several layers of insulation tape, followed by a layer of duct tape over the whole exposed length and then as further protection I've used spiral wrap over the top of that.




Once the car was back on the ground I checked which way the brake pipe and wire flexed. I've had to deliberately move it so it curves away from the wheel. I'll probably have to monitor it.

The test drive went well with everything working as it should and no warnings.

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