Not again – 00290 ABS Wheel Speed Sensor

[andybaggies]

I’ve just had this code ping up again for the same wheel, rear left, as 3 months ago. In that instance Audi replaced pretty much all the parts, sensor, cable and finally the bearing which cured the problem.


However it’s now returned, it was ok the night before when I parked up, and appeared when I drove off in the morning. So I’m starting to worry it may be the main (expensive) ABS controller that may be duff.


Has anyone had experience of such & if there’s any way of diagnosing the issue?


Cheers,

Andy B

 

[timmus]

Has the bearing slipped slightly (in the left-right direction) such that the excitor ring is no longer in range of the sensor? I've known this happen on the A2's front bearings, but I don't know whether it's possible at the back.

Tom

 

[spike]

Has the bearing slipped slightly (in the left-right direction) such that the excitor ring is no longer in range of the sensor? I've known this happen on the A2's front bearings, but I don't know whether it's possible at the back.

Tom

The rear hub unit incorporates the bearings and oil seals and is held in place by a large nut which is hidden by a tin dust shield. (I think the sensor ring is incorporated within the inner oil seal) If the nut loosens, the whole hub could move axially and loose the signal from the ABS sensor ring as you suspect.
It should be easy to detect by jacking up the car and 'working' the back wheel to check for excessive end float.

Cheers Spike

 

[andybaggies]

Thanks guys. I'll have a look at the weekend and also give the sensor/connectors a clean and squirt of WD - hopefully as the sensor is only a couple of months old it shouldn't be seized in solid.

I'm assuming the nut is nylocked, but it's a little concerning the hub nut could of loosened....

Cheers,

Andy B

 

[spike]

The nut is self locking and it would be very unlikely to come loose providing it was torqued correctly and the old nut was not re-used.

Cheers Spike

 

[andybaggies]

Well this has also being resolved by Vince. With the knowledge of the replaced sensor & wiring he suspected the bearing was probably amiss so to test the idea he decided to swap them over between the rear wheels. And when doing so he noticed there was an awful lot of brake dust & assorted debris. A quick clean and replacement and all was sorted.

So I'm now wallowing in the luxury of not having 3 beeps within the first 100 yards and a continuously flashing exclamation mark for the rest of the journey. Such joy

Andy B

 

[timmus]

So I'm now wallowing in the luxury of not having 3 beeps within the first 100 yards and a continuously flashing exclamation mark for the rest of the journey. Such joy

I know how you feel! I tolerated the beeping and the flashing for some months before handing this job to Vince when he did my gearbox. It really is a luxury to return to dash normality.