ABS issue

[H9 DUB 0]

I have a 95 VR6 which has been trouble free untill the other week, when i did a trackday at my local circuit (Knockhill). Now the breaks did take a fair pounding and they were smoking a bit when i first came off the track :lol: Returned home later and everything was ok.

However the next day when i turned the car on the abs light would not go out as it usually would once the car was running. Was hoping someone would have a rough idea of what might be wrong?

I have stripped all the breaks Discs,pads,callipers, carriers and hoses for an overhaul over the past couple of days, i checked the abs sensors and rotors and they are all intact and in the right positions, gave the sensors a good clean as there was a fair bit of brake dust. Now im just waiting to get the new discs to fit it all back together, but im wondering if i will need to change a sensor.

Could a fault occur on a sensor purely due to high temperature or does this sound like something else?

Will try and get the car onto VAGCOM once the brakes are rebuilt to see if there are any fault codes, ive got my MOT due on the 20th so need to get this sorted!

 

Any ideas?? :?

[dirtytorque 0]

See what vagcom says.

It the only way to isolate the fault sensibly.

anything else would be just guessing if you can't see anything obvious with the sensors,cables etc.

 

 

Its probably just a tired wheel speed sensor or it could be that you just need to clear the fault codes which sometimes works as well.

 

good luck.

[StuartFZR400 0]

I take it you're aware that there are different VAGCOM connectors depending on the car. Being a 95 I'd guess yours is the large female-plug, found under the cover that goes over the gear stick. Make sure your fiend/garage has the right one.

 

VAGCOM will give you the answer and save you buying stuff for no reason. Buying a full set of 4 sensors is not cheap - I know.

 

I presume you looked at front and back. And presume the front discs came off - cannot remember if you said. Therefore also check rears are clean. And I presume when you turn the ignition on now that the light still stays on. Putting new front discs on the front will make no difference as if they're like mine, the holey ring for the ABS is not part of the disc-brake.

 

Worth disconnecting the ABS sensors at the front, clean them with contact cleaner and put back together, as dust could've got in there. The rears are sealed up until where they connect under the rear seat/bench. NB: harsh blows to the sensor can knacker them, as they're magnetic. GSF ones are kinda-cheap and easy to install.

 

HTH 8)

[H9 DUB 0]

Cheers guys, yeah i thought VAGCOM would be the best place to start. staurtFZR400 Yeah checked front and back sensors and all the brakes have been stripped as i destroyed a pad on the trackday and scored a disc, thats the only reason im replacing them.

New Black diamond discs arrived today just waiting on Goodridge hoses and i can put the whole lot back together 8)

[dinkus 10]

It could be that the temperature has distorted one of the ABS cages, or dislodged a sensor.

 

I really wouldn't do a track day with the ABS running though as you're likely to cook the ABS pump. It's designed to be used every now and then and using it every few seconds on the track will likely damage it.

 

The best way to disable it is to just yank a sensor wire - one of the ones on the front suspension struts are the easiest to get to.

[H9 DUB 0]

Do you mean an ABS rotor Dinkus? If so i did check these for distortion and cracks also and they appear to be fine. I didnt realise that it wasnt a good idea to run with the ABS at track days, never really felt it coming in as i was trying to progressivly brake rather than braking late and stamping on the anchors. But i understand what you mean and will try it if i ever do another trackday

[dinkus 10]

If you weren't using it much then you should be ok - some people go around stamping on the pedal and letting the ABS do all the work then wonder why all their brake fluid is gushing out of the ABS pump after 3 laps :lol:

 

My guess would have been the rotor thingies with the slots in, yeah. If they all look ok then not sure really, but VAG-COM should be able to tell you.

[H9 DUB 0]

Ok dinkus , that will be my next port of call !

 

Cheers Ewan 8)

[dinkus 10]

Yeah sorry - after all that back to the time honoured "plug it into VAG-COM mate" :lol:

[mr.ots 10]

You could always check the resistance of the wheel sensors using a multi meter. I changed my NSF one today and it's cleared the fault I had.

 

The resistance doesn't need to have increased too much from the average value of around 1100 ohms to cause a fault as my NSF sensor was reading 1400 ohms which was putting the ABS warning light on. If you had generated a lot of heat through the brakes while on track it may have heated up the sensor enough to cause a permanent increase in its resistance.

 

Might be worth checking first if you don't have immediate access to VAGCOM.

 

The GSF sensor is only £18 so quite a cheap fix if that's your problem.

[yeti 0]

The GSF sensor is only £18 so quite a cheap fix if that's your problem.

 

i payed vw prices last week and the standard rrp is about £40 a side! :oops: i should hahve called them

[H9 DUB 0]

Ok will try metering the sensors then mr.ots Cheers

[H9 DUB 0]

Measured the resistance of the abs sensors today - the passenger side is 1075 ohms and the drivers side was off the scale, so it appears i may have a faulty sensor.

Cheers for the advice mr.ots :D