Here's the story. 1998 manual 528i with sports/premium package.
Bought the car with ABS/ASC lights on. Took it to an independent BMW dealer. The scan tool said front right speed sensor is out, so replaced it and cleared the codes. On the test drive, the car started braking on it's own at exactly 12km. The light came on again, and from then on drove alright. Back to the shop, cleaned the RF sensor, rechecked, cleared codes and test drove again, with same results, being at 12kmph the car braked by itself and the light came on again, and would drive ok(system shut down?)
Brought back, put the scan tool on the port and test drove withe tool attached while tech watched the screen in the passenger seat. The RF sensor indicated 5km, when the other 3 wheels indicated 15km (same all the way upto 30km)
I suggested the new sensor is faulty.
The hub was replaced on the same wheel by previous owner, and the tech says the hub may have been installed wrong, and results in a wrong reading from that wheel, or the module is faulty. I'm going to switch the front sensors around tommorow and do a little test of my own. Anyone else had a similar issue guys? Thought of checking before I started throwing any more $$$ away.
For your help