intermittant abs warning light

[jonny87]

as title says, abs light on dash comes on and off randomly

get in car, its not on, few miles down the road notice its illuminated, get to destination may have gone off or the next time i go to drive the car it will have switched off, has been off for last few days...

when illuminated my abs is def not working (checked this by dropping anchors at 40mph)

have read threads on here about abs faults, couldnt find a thread that described my symptoms exactly, but have checked three fuses on top of battery, all looked ok but will replace anyway

other than being a faulty abs pump (which i hope it aint) i read it could be a wheel speed sensor?

i know it needs plugging in to get codes but currently dont have access to vcds or similar, so am just seeing if anyone would have any other suggestions for the mean time?

anyone know if the abs system is earthed via the rear diff, as i think my earth strap is shagged and this could be the cause of the problems?

any input appreciated
jon

 

[jojo]

Definitely need to VagCom it mate, it will show up any faulty ABS/Speed sensors in your circuit.

 

[audi5802]

hi mate i had same problem on my a4 b6 sport same symptoms.abs light and traction control light kept on coming on and off at same time. does the light seen to come on when your braking or randomly??? when you press your brake pedal do the rear brake lights come on still or not as after alot of messing about on mine it turned out to be a brake light sensor on my car cost me a tenner and taking bottom steering wheel dash off and taking old sensor out push in new one and twist. my problems were solved lol. takes 20mins max to fit. hopefully its that mate

 

[jonny87]

jojo, yer i know, could one of many things but wont be getting plugged in till next week earliest

audi5802, i havent noticed it coming on specifically when braking but then again i havent been watching it, but its def a possibility so will keep an eye on it today when driving, will check to see if brake lights still work, did yours not work then when you had the problem?
the sensor you mentioned is it the one that is located above the brake pedal, similar to the clutch switch? are they adjustable like the clutch switch?

 

[NHN]

Give the abs sensors a clean of brake dust/filings mate, also unplug them & check for any crap in the connectors as the sensors get caked up with this after a while, worth a try & its free as in your time only.