intermittent ABS light issue

[deejames]

Hi,

sometimes my ABS light does n`t go out when i start the car, normally the next time i start it or at least by the next day it goes out as normal. Not sure what to suspect at this point - i`ve read a few posts but have n`t found one describing the exact same set of symptoms. The car is a 1998 A4 Avant auto.

Thanks in advance

 

[Ian2012]

sounds to me like the abs brain on the side of the abs pump is failing, is it temperature dependant??? a scan with vcds will tell you,it may say something like "intermittent or sporadic communication" if it is that problem then the brain can be removed from the pump and sent away for repair.

 

[deejames]

Hi Ian,

there doesn't seem to be any pattern to it, some times the light goes out sometimes it does n`t. Yesterday morning it was fine but in the evening it wouldn't go out again. Sometimes if you restart the car it goes out. I did think it might be a dodgy connection somewhere but it does seem to be happening more often.

 

[Ian2012]

Classic sign of brain failure, usually it's worse when it's cold as temps rise both air temp and engine temp (heat soak) expands the connections and it's usually ok again. that was my experience, this is what i wrote on another forum
ABS Controller Repairs - Audifans.net

 

[deejames]

cheers for that Ian, i`m going to send off for a lead from Gendan and download the vag com lite software (probably going to come in handy more than just this occasion) to confirm it but it does sound like you're right. Hopefully i can locate a replacement rather than having to send it off for repair

thanks for your help

 

[Ian2012]

Brain removal is easy, it screws to the side of the pump, you can still drive the car without abs whilst the pump is being repaired, you really don't want to be fitting a complete new pump as that's just a ball ache trying to bleed them