ABS Issue/Anti-Lock Light

[E30Bastard]

The inside of my hub...just in case...idk... Sent from my Pixel 2 XL using Tapatalk

[moatilliatta]

Id try the old axles again.

[VitalkaE30]

Bump. Was this ever solved? Currently chasing the same issue

[zaq123]

Bump. Was this ever solved? Currently chasing the same issue

Unplugged all the sensors and did spin test - Both front sensors set the light off and both new rear sensors do not.

It's kind of hard to follow OP's posts in this and his other linked thread about CV axle issues. If all sensors are unplugged, how can front sensors set the light off?


In any event, here is some useful info from the man - the legend himself

ABS Diagnostics

The ABS system on an E30 is pretty simple. It consists of a wheel speed sensor at each wheel, and ABS module & relay above the steering column, and the ABS unit in the engine bay. It has no connections to any other parts of the car.

If the ABS light comes on when the ignition is turned on and doesn’t go off when the engine starts the relay, module and unit are all suspect. There is a fusible link in the ABS relay that, if blown, will cause this. The fuse (a simple piece of wire) can be replaced, or better yet get a new relay. If that fails to solve the problem the ABS module or the ABS unit are the next suspects. The ABS unit contains relays that have been known to fail and can be replaced with OE parts. So you have two choices. replace the ABS module with a known good unit, or replace the relays or the entire ABS unit. I start with the ABS module.

If the light comes on with ignition, goes out with engine start, and comes back on once the car starts moving, one (or more) of the wheel speed sensors is bad or the ABS module is bad. A simple test of the speed sensors is to disconnect all but one and see if the light comes on while driving. Since the ABS system only gets speed data from the wheel speed sensors, a good sensor will cause the light to come on as the module doesn’t see data from the other sensors. Repeat this test with each of the other speed sensors. A bad one will cause the light not to come back on as the ABS module can’t tell that the car is moving. Replace that sensor(s) and see what happens. It is possible that one or more of the input channels in the ABS module are bad.

[hopeful]

There has to be some form of diagnostic process to this aside from what's above? I can't imagine this is what dealer Tech's we're doing when the abs light came on. Maybe some older generic abs scanner would work?

[ghrays]

I had a similar issue with intermittent flashing of the ABS dash light. Turned out to be due to a faulty connection at C101 (pin 20).