A2 abs fault

[tidla]

hi all.
Warning light on the dash came on, fault code read which pointed at nsf abs speed sensor fault. the wiring to the sensor was checked and found to be split/open circuit and possibly touching each other.
This was repaired, rechecked, same code back again.Wheel sensor also replaced. Dash cleared and no codes returning.
On test drive however the abs kicks in under low low braking at all speeds.
A speed signal is received from all wheels in vcds and a scope of the pattern looks good from each wheel.

Abs pump/ ecu time?

thanks.

[zollaf]

normally in this situation i would expect to see a sensor dropping out to trigger the abs. electronically its checking out ok as no light or codes, so i would check all air gaps and abs rings. give everything a clean up and see what happens. often it can be a bit of rust on a reluctor ring or even a broken one. i have just fixed a similar fault on an lt35 and that was rust pushing both rear sensors up, thus the airgap was too big.

[boustie]

sympoms of dirt on one of the ABS sensors