hi,
my saphire cosworts abs light come on sometimes and stays on untill i turn the ignition off again. it became more frequent and now basicall ay soon as i pull away it comes on. sometimes its ok and dousent come on at all. it passes its self check when the ign is switched on (lamp illuminates and then goes out)
iv measured the resistance of al 4 sensors, they are all ok @ around 1000 ohms.
one thing iv noticed is that both rear sensors are cracked where the bolt goes through but they seem secure and still inserted all the way, but could this be my cause?? the wiring by the turbo seems ok.

 

Check the AC voltage produced by the sensors. Jack the car up, turn the wheel at approx 60 rpm and measure the voltage - should be 0.15V.

 

yer good shout. il do that nnext, an occillascope would be easier, mite picup a dodgy tooth on a fing gear. thanks il try that

 

Had the same problem a few years back and it was caused by the passengers side front wheel sensor. From memory the resistance between the two wires read O.K. as yours do but the earth shield is not at earth potential and was shorting to earth through a chaffed outer insulator. At the ABS module connector check the resistance between the earth shield side of the cable and actual vehicle earth and see if one reads different to the other 3. Just a thought. Actually have the same problem again now but haven't looked into it yet.

 

ok i will do that thanks buddy

 

just to update, my abs is fixed, i replaced both front wheel speed sensors and bingo.