ABS Pump stays on (buzzing) even when car is off

[tonerrrr]

Cross post from S14.net since I didn't get any response there, this is regarding a 90 M3:

My ABS light had come on at some point over the weekend which I thought "oh maybe it's that relay fuse that was busted in my other e30 and I fixed easily..." well, the light went off the next time I drove the car, then it came on again, and again. So it must not be that relay fuse but I suppose it could still be that.

The real problem (aside from no ABS racecar status) is that last night, when I parked my car and shut the engine off, the ABS pump was buzzing away. I unplugged Fuse 6 (abs) and the pump stayed on, I started the car then turned it off and the pump stayed on, so ultimately I just disconnected the battery to save it from dying.

Anyone else have this problem? Looking around it seems the first thing to do is clean the ABS sensors, then I'll check that relay though it would be weird for the pump to stay on if that fuse was broken... Also, I'm going to try and reconnect the battery, maybe I didn't have it off long enough to reset whatever and see what happens.

Any insight is much appreciated, I'd like to try to and fix this before going full racecar, so "ditch the ABS" comments are not helpful until I've toiled over this problem for at least a few weeks ha!

[jlevie]

The ABS unit buzzing with the car stationary sounds like a problem with the ABS module or ABS unit.

[tonerrrr]

It turns out it was just a relay in the ABS pump stuck in the on position. To test this, I just hooked the battery back on, pump was buzzing away, and I lightly hit the black cover of the ABS with a socket wrench and it immediately turned off.

For those possibly googling, more on s14.net: http://www.s14.net/forums/forumdispl...-M3-Discussion

Once I get the problem completely fixed I'll update this thread with what relay part I went with/fixed it with.