ABS problem on my TDI Quattro...

[RadCap]

Hi guy's, I have a problem with my A4. The ABS light comes on intermittently. I know there is an actual problem as my front right (o/s/f) locks up under heavy braking.
I did buy a new sensor assuming it was that corner that was the problem and fitted it but it hasn't gone away.
The other wheels seem to 'work' OK.
It varies day to day, when or how much it comes on.
But generally it's on all the time

I noticed while changing the front there was mud and crap on the ABS ring (which I cleaned)... But surely if it was that, it would come on all the time, yes?

 

[ian52]

what age is the car?

 

[RadCap]

Sorry, it's a '99

 

[aragorn]

you need to scan it with vagcom, which will tell you which sensor is causing the problem

 

[ian52]

my money is on the controll module. on the later b5's they seem to be prone to going.

 

[aragorn]

they tend just to fail outright though. Sounds more like a sensor fault to me?

 

[ian52]

mine was giving sensor faults but it was the unit itself.

 

[RadCap]

Thanks guy's. I went out today and it never came on until I hit a small bump in the road after about 30miles.
Like I say, sometimes it comes on straight away and sometimes not...

It's ****** annoying now though!

 

[aragorn]

I think with it being intermittant does sound like a sensor, but the only way to be sure is to scan it with vagcom, then take a look at the sensor in question.

The biggest issue is that it could be the sensor, the reluctor on the CV, the wiring, or none of those, and its actually the module thats dead.

I'm sure ians dead module was showing as faulty all the time?

 

[ian52]

It started out intermittent but got worse. On vagcom it was showing a sensor fault even after fitting a new sensor.

 

[RadCap]

Thanks, I wouldn't say it is getting any worse or better.
I am going to examine the wiring and sensors today as I'll be doing the pads all round...
But I take everyt