ABS Woes (2003 1.4tdi 75)

[hoverdog]

Newbie here again, finally got my barn find A2 through the MOT and on the road, within a 100m of the testing station the ABS warning lights came on. OBD reader throws up codes 285 and 275 which both refer to the RHS front and rear. So far I've: replaced front right ABS sensor, removed and cleaned up (both) rear sensor rings (both rings were intact) but codes 275 and 285 persist. Logically, the next steps would be to a. replace rear RHS sensor and b. replace front sensor ring. Could any one give me a description of the sensor ring? Internet searches seem to be a bit vague as to what the ring looks like. Any info or advice would be most welcome.
On the plus side, Barney was a bit sluggish the first few days but having cleared some engine fault codes (18039,17554, 17553, 17978 and 18027) with the OBD reader, he is now a surprisingly nippy little mover.

 

[greywolfhound]

Newbie here again, finally got my barn find A2 through the MOT and on the road, within a 100m of the testing station the ABS warning lights came on. OBD reader throws up codes 285 and 275 which both refer to the RHS front and rear. So far I've: replaced front right ABS sensor, removed and cleaned up (both) rear sensor rings (both rings were intact) but codes 275 and 285 persist. Logically, the next steps would be to a. replace rear RHS sensor and b. replace front sensor ring. Could any one give me a description of the sensor ring? Internet searches seem to be a bit vague as to what the ring looks like. Any info or advice would be most welcome.
On the plus side, Barney was a bit sluggish the first few days but having cleared some engine fault codes (18039,17554, 17553, 17978 and 18027) with the OBD reader, he is now a surprisingly nippy little mover.

I had same but my issue was the yaw sensor ... If it is that with yours there are plenty available e bay s/h for that year car at a cheap price..not with my early one ..

 

[A2Steve]

Have you checked your abs looms for splits in the wire?

 

[hoverdog]

I had same but my issue was the yaw sensor ... If it is that with yours there are plenty available e bay s/h for that year car at a cheap price..not with my early one ..

I think any faults with the yaw sensor have a different code, thanks for the input tho

 

[hoverdog]

Have you checked your abs looms for splits in the wire?

all the cabling is well out of the way of moving parts and looks intact, I've checked continuity and it all is good.

 

[audifan]

Do yourself and every one else a favour and have a VCDS scan done. Generic are just that and many generic codes do not translate well to the A2. Just now you are guessing and "loading the parts cannon"

 

[hoverdog]

Do yourself and every one else a favour and have a VCDS scan done. Generic are just that and many generic codes do not translate well to the A2. Just now you are guessing and "loading the parts cannon"

Cheers, will do

 

[kp 115]

Newbie here again, finally got my barn find A2 through the MOT and on the road, within a 100m of the testing station the ABS warning lights came on. OBD reader throws up codes 285 and 275 which both refer to the RHS front and rear. So far I've: replaced front right ABS sensor, removed and cleaned up (both) rear sensor rings (both rings were intact) but codes 275 and 285 persist. Logically, the next steps would be to a. replace rear RHS sensor and b. replace front sensor ring. Could any one give me a description of the sensor ring? Internet searches seem to be a bit vague as to what the ring looks like. Any info or advice would be most welcome.
On the plus side, Barney was a bit sluggish the first few days but having cleared some engine fault codes (18039,17554, 17553, 17978 and 18027) with the OBD reader, he is now a surprisingly nippy little mover.

Hi hoverdog,
This is a photo of a AMF 1.4 tdi
Front hub/wheel bearing assembly, abs ring is shown by blue arrow with attached debris

 

[hoverdog]

Hi hoverdog,
This is a photo of a AMF 1.4 tdi
Front hub/wheel bearing assembly, abs ring is shown by blue arrow with attached debris View attachment 87557

Now that's what I'm looking for and thanks for posting it. From what I gather, on the interweb there appear to be two different types of ring - one looks to be solid (as on the rear bearings) and the other looks to be slotted (making the ring look almost like a very narrow toothed wheel). I wonder what the blue arrowed one looked like when the assembly was new?
Cheers mate

 

[kp 115]

Now that's what I'm looking for and thanks for posting it. From what I gather, on the interweb there appear to be two different types of ring - one looks to be solid (as on the rear bearings) and the other looks to be slotted (making the ring look almost like a very narrow toothed wheel). I wonder what the blue arrowed one looked like when the assembly was new?
Cheers mate

I’ll post a picture tonight when I get home I’ve got one in my box,
But it’s a semi opaque surface with the magnetic segments underneath, all that debris is sitting on top of the segmented ring!!!
Rust & fillings from the disc etc.
But it s actually the surface directly at the tip of the blue arrow.

 

[hoverdog]

I’ll post a picture tonight when I get home I’ve got one in my box,
But it’s a semi opaque surface with the magnetic segments underneath, all that debris is sitting on top of the segmented ring!!!
Rust & fillings from the disc etc.
But it s actually the surface directly at the tip of the blue arrow.

Any luck with that photo mate?

 

[kp 115]

Any luck with that photo mate?

Sorry at work 90 miles from home will get photo of old & new bearing but it’s exactly where the arrow touches all the debris on the photo, not the ring around the bearing it’s only accessible from the rear of the disk/driveshaft area , put wheel on full lock to the right & you should be able to see the sensor coming through the hub

 

[audifan]

So I take it you have had a VCDS scan done and from that concluded it is a bearing issue?

 

[spike]

Not exactly the best description but this youtube video shows the magnetic sensor ring which is integral with the rear bearing seal
Cleaning off any debris from the surface of the seal is worth a try but may not be the solution

Cheers Spike

 

[kp 115]

Any luck with that photo mate?

It’s the brown ring, second photo shows faint tangential lines , it’s really hard to photograph.

 

[kp 115]

Not exactly the best description but this youtube video shows the magnetic sensor ring which is integral with the rear bearing seal
Cleaning off any debris from the surface of the seal is worth a try but may not be the solution

Cheers Spike

That is what I’ve been trying to capture , ?
Thanks
Spike

 

[hoverdog]

That is what I’ve been trying to capture , ?
Thanks
Spike

Spike, you are a gentleman and a scholar! I followed your advice for checking the sensor from the back of disc/driveshaft and the ring has delaminated, an endoscope into the hole left by removing the sensor also confirmed this. The bearing itself seemed to nice and smooth in rotation tho. Seeing as you have to take the bearing out to replace the ring I might as well just replace the bearings (once I find a local garage with that snazzy bearing removal tool). Cheers, Paul.

So I take it you have had a VCDS scan done and from that concluded it is a bearing issue?

Didn't get as far as the VCDS scan, just followed Spike's suggestion for visually checking the ring and it was kaputt. Once (and if) the weather clears I'm going to hook up the rear sensor to an oscilloscope and check the sensor output on rotating the hub. Cheers mate.

 

[hoverdog]

Spike, you are a gentleman and a scholar! I followed your advice for checking the sensor from the back of disc/driveshaft and the ring has delaminated, an endoscope into the hole left by removing the sensor also confirmed this. The bearing itself seemed to nice and smooth in rotation tho. Seeing as you have to take the bearing out to replace the ring I might as well just replace the bearings (once I find a local garage with that snazzy bearing removal tool). Cheers, Paul.

Didn't get as far as the VCDS scan, just followed Spike's suggestion for visually checking the ring and it was kaputt. Once (and if) the weather clears I'm going to hook up the rear sensor to an oscilloscope and check the sensor output on rotating the hub. Cheers mate.

ABS Sorted!! But what a journey. New front bearings, new NSF CV joint (old one had seized driveshaft), new OSF speed sensor, new OSR speed sensor (after helicoiling in a new mounting thread for the mounting screw-the old screw was seized in the thread). Next on my to do list will be to find out how I can achieve the 60+ mpg often referred to on the forums, my best yet is 52.