FR TDi ABS Issue

[st@rgixxer]

Righto folks, got an ABS sensor issue in my car, Nearside Rear this time, had the Offside Rear go last year, which just needed a new sensor.

So this time, I've changed the sensor, but still getting the same fault codes...

00290 - ABS Wheel Speed Sensor; Rear Left (G46)
012 - Electrical Fault in Circuit - Intermittent
00290 - ABS Wheel Speed Sensor; Rear Left (G46)
003 - Mechanical Failure - Intermittent

... which obviously bring up the ABS, TP monitor, TCS and Steering warning lights on the dash.

So I did a graph log on the car with the new sensor in (graph compares nearside rear (red) to offside rear (green). The Red line looks very erratic to me....



Does anyone know of a way to test the wiing loom to the sensor (i.e. what resisitance it should be..?).

Apart from that, from some research looks the the ABS ring on the back of the hub may have gone (it does look a bit corroded - car is on 77k) - which would be a new hub...

Any advise or ideas much appreciated...

Cheers, Kev.

 

[James_R]

The mechanical fault is the hub, the hub is probably so corroded its started cutting into the abs sensor. Common issue, take the hub off to confirm.

 

[st@rgixxer]

Yeah, looking from underneath with a torch I can see the ring is a bit corroded and the old sensor was being rubbed, I had to put a thin washer between the new sesor and the rear of the hub to create a 1mm gap.

Thanks for confirming, I'll get a hub ordered up.

What is the fitting inside the cap, apparently a special socket required??? (I've got the splines for taking the caliper mount off).

 

[James_R]

It's a large spline, either m14 or m16. A breaker bar and scaffold pipe normally makes easy work of them.

 

[Nath.]

Can't you use a wire brush attachment on a drill to remove the rust from the ABS ring?


Another good way to remove rust from steel is to soak it in vinegar. Here's a before/after pic http://zedomax.com/blog/wp-content/uploads/2009/02/diy-rust-removal.gif


Give it a go as it may save you some £

 

[st@rgixxer]

Well, finally got the new hub fitted today, turned out to be M18 Spline tool needed (borrowed one from my local indy garage tonight).
Job wasn't too hard after all, although I did need to get a mate who is 'slightly larger than me' to help me crack the hub bolt off..... 170ft/lb my @rse... was on atleast 200!

My torque wrench only goes to 153, so did that and a good bit more and some loctite.... faults all gone.

Thanks for your input guys.