ABS Light on A3 Tdi

[BigBazza]

Hello Everyone,

Im a closet Audi fan, the Mrs never drives anything but, and I am trying to help my nephew save a few quid with his.

He has a 1999 A3 Tdi, and its just failed MOT as it has the ABS warning light on permanently - he is being quoted silly amounts by auto electricians just to locate the fault, not to fix it.

Just wondered if anyone had this fault and if so, what you did about it?

Thanks

[carrotchomper]

[NicholasCage] Take the FACE OFF, the FACE OFF... sorry. take the bulb out? [/NicholasCage]

[dubkiller]

you need a vag com man to help you .

[BigBazza]

He cant do the bulb out, wire cut thing as the bulb is supposed to illuminate for 2 seconds on ignition then go out.

Diagnostics guys are going to charge him and arm and a leg.

Thanks for suggestions so far.

[dubkiller]

most independants charge about 1/2 hr labour ish to put on vag com.
£20 ish ?
at least you will know which sensor at fault.

[rfisher]

I've just bought a fault code reader on Ebay for £15 for this problem on my A3 Tdi.

[Ahonen]

I only have an old Quattro but the principle might be the same so I'll offer an answer.

Sometimes the ABS sensors get nudged slightly if the car has had some recent work done on the suspension or brakes. On mine it happened after a the strut tops were changed - one of the sensors was too far away from the ring and couldn't 'see' it, so permanently thought that the wheel was locked. A quick fiddle with each of the sensors (cleaning and realigning) in turn eventually located the cockeyed one and all was fine again.

Could also be caused if the ABS ring is particularly dirty and full of gunge, as the sensor won't read pulses properly. This has also happened to mine.

Modern cars (mine's a 1990) might be more complex, but it's worth a couple of hours of tinkering before sending it to someone who'll charge silly money.

Edited by Ahonen on Tuesday 3rd July 20:42

[dubkiller]

oh. also if you have access to a ohm meter , as a general rule each sensor will give about 800 - 1500 ohms .
always worth testing.

[LaSarthe&Back]

tell him to sign up on audi-sport.net

Then post this info and ask if anyone close to him can do a VAG-COM scan on his motor. This should point towards the fault, and help towards fixing it.

have ALL the fuses been checked?

[roosevelt]

Just wondering, can they fail the MOT for a warning light? What if the brakes are ok and its aomething else (eg electrical fault) causing the light to be illuminated... anyway if the ABS warnig light is on the brakes still work... is an ABS car with failed ABS system (but working brakes) doomed to fail and a non-ABS car with working brakes to pass??

ps please to hear the best way to get an answer as I have this on my Mk3 Golf.. ABS warning light comes on and stays on for rest of journey (occasionaly not always!), then is OK next time when engine started!!

[LaSarthe&Back]

roosevelt said:

Just wondering, can they fail the MOT for a warning light? What if the brakes are ok and its aomething else (eg electrical fault) causing the light to be illuminated... anyway if the ABS warnig light is on the brakes still work... is an ABS car with failed ABS system (but working brakes) doomed to fail and a non-ABS car with working brakes to pass??

I believe so. I think they class it as a failure of equipment or something like that. Much like an airbag light, if it's on, it could go off as soon as you leave the test station. Just like the brakes could fail when you leave.