freeflyer

Six months ago the ABS warning light appeared on the dash of my Audi A3 1.8 TFSi (2007, 8P).

Using VAGCOM I found that the issue was with the rear right wheel speed.

I changed the sensor but this did not fix the problem, so I changed the wheel bearing (which has the magnetic ring on it) and found that the original was badly corroded. The new wheel bearing fixed the problem and all was good.

Recently the rear pads were badly worn - the pads on the wheel that had the corroded magnetic ring on the bearing were almost down to the metal.

I changed the rear pads but then shortly after the ABS warning light appeared again, Using VAGCOM I found that the issue was with the rear right wheel.again !

I could only presume that maybe the worn pads caused the sensor or the magnetic ring to fail, maybe by overheating or debris ?

So, I changed the sensor again but this did not fix the problem, then I changed the wheel bearing again but this did not fix the problem.

I checked the magnetic ring on the wheel bearing I removed using a magnetic viewing film and it seem to look fine...




When I log the wheel speed with VAGCOM and spin the wheel it permanently reads 0kph.

When I unplugged/plugged the sensor I sometimes heard a beep from the dash board and sometimes there was a blip on the signal logged on VAGCOM

I have connected some wires near to the sensor connector to look at the signal on an oscilloscope. The scope shows battery voltage so the sensor is getting power and therefore it cant be a wiring fault, but there are no pulses when I spin the wheel (the level remains at battery voltage).

The sensor air gap can be seen in the picture below...




My MOT is due in a week so I need to get this sorted but I'm at a loss as to what the problem is.

I bought the sensors and wheel bearings from GSF (fortunately with 60% discount)...

https://www.gsfcarparts.com/413vg0450

https://www.gsfcarparts.com/648vg0260

Surely the sensors or wheel bearings cant be faulty having replaced both of them twice ? Or are they very poor quality ?

Has anyone else had this issue or have any suggestions on how to fix ?

The fault description from VAGCOM is below...

Address 03: ABS Brakes Labels: 1K0-907-379-MK60-F.lbl
Part No SW: 1K0 907 379 AC HW: 1K0 907 379 AC
Component: ESP FRONT MK60 0101
Revision: 00H11001
Coding: 0021122
Shop #: WSC 06314 000 00000
VCID: 73EE262112AD8DDC2A-8026

1 Fault Found:
00287 - ABS Wheel Speed Sensor; Rear Right (G44)
008 - Implausible Signal - Intermittent