ABS LIGHT SAYING ON

[shawsy]

My a3 SE FSI 2003 failed an MOT and ive replaced all the parts it failed on but still cant get the ABS light to go off. Is this a common problem and where's the first place to start looking to find this fault? I understand it could be many things but what would normally be the first thing to cause this light to stay on.

Thanks in advance

[Steve Q]

Hi David I'm not completely sure to be honest but I besides the usually culprits like failed abs sensors or abs wiring, I think rust can build up near to the sensors connectors in that area and it causes the sensor to think there is a fault. This area needs clearing of the surface rust and you should be good to go. 

The person who will know is Gareth (magnet) he's very good on this sorted of thing :) 

Cheers

Steve 

[Magnet]

Hello David,

I think Steve is on the right lines here. Just because I'm in my dotage, and probably have shirts older than him, he mistakenly believes I'm good with these things - bless him he's losing it! 

Yes David, I would be looking at the toothed rings (about 3 inchs in dia. in old language)  on the wheel ends of the front drive shafts, and I think (see, I'm not  so good on these things) just behind the rear hub at the back. 

As Steve says, check these rings carefully for rust, since the sensor picks up the gaps between the teeth. If one or more of them are rusted then the sensor can throw a wobbly. Clean off any rust you can find, but you are really looking for crusted rust rather than surface rust. Not sure if you may have to reset the light after?? Could be wiring or a faulty sensor if you find all looks well with he rings.

Last resort could - just could - be a fault in the ABS units. I know there was a "commonish" fault on these a bit later. This was fixable by replacing a "part AbS unit". Fingers crossed its just a bit of crusted rust.

Kind regards,

Gareth.

 

[Steve Q]

1 hour ago, Magnet said:

Hello David,

I think Steve is on the right lines here. Just because I'm in my dotage, and probably have shirts older than him, he mistakenly believes I'm good with these things - bless him he's losing it! 

Yes David, I would be looking at the toothed rings (about 3 inchs in dia. in old language)  on the wheel ends of the front drive shafts, and I think (see, I'm not  so good on these things) just behind the rear hub at the back. 

As Steve says, check these rings carefully for rust, since the sensor picks up the gaps between the teeth. If one or more of them are rusted then the sensor can throw a wobbly. Clean off any rust you can find, but you are really looking for crusted rust rather than surface rust. Not sure if you may have to reset the light after?? Could be wiring or a faulty sensor if you find all looks well with he rings.

Last resort could - just could - be a fault in the ABS units. I know there was a "commonish" fault on these a bit later. This was fixable by replacing a "part AbS unit". Fingers crossed its just a bit of crusted rust.

Kind regards,

Gareth.

 

There we are! I knew you would know the technical terms and the potential faulty parts Gareth :) don't doubt yourself Gareth! You always give fantastic answers and I remember a previous topic some months back where you diagnosed this fault correctly ;) 

[shawsy]

Cheers guys i'll have a look and get back to yous. Thanks again

[Steve Q]

10 hours ago, shawsy said:

Cheers guys i'll have a look and get back to yous. Thanks again

Your welcome :) glad we could help :)