Unable to reset rear brake service light

[minirips2]

I guess the title says it all. I purchased my 128i from a dealer who put new brakes at all 4 corners. The rotors had rust pitting where the pads contact them, and the pedal pulsated, which drove me nuts. Since the rotors were basically new, I just had them surfaced, and reinstalled them. That was two weeks ago, and the brakes feel mint. Plenty of pad left, both front and rear. So now I have a service light (car on lift), and the brake indicator light stays on. I tried to reset the indication with my Schwaben (Foxwell) tool, and it won't let me reset the rears. Any ideas? I'd check the rear brake sensor, but it's raining like a mother out!

[bNks334]

Originally Posted by minirips2

I guess the title says it all. I purchased my 128i from a dealer who put new brakes at all 4 corners. The rotors had rust pitting where the pads contact them, and the pedal pulsated, which drove me nuts. Since the rotors were basically new, I just had them surfaced, and reinstalled them. That was two weeks ago, and the brakes feel mint. Plenty of pad left, both front and rear. So now I have a service light (car on lift), and the brake indicator light stays on. I tried to reset the indication with my Schwaben (Foxwell) tool, and it won't let me reset the rears. Any ideas? I'd check the rear brake sensor, but it's raining like a mother out!

No idea what a Foxwell tool is, but service warnings are reset through the indicator stalk...

Was the old sensor worn down to the point where the service light was on previously? The dealer probably re-used the old sensor, or didn't put a sensor back in at all. If this is the case, you can cut the sensor wires and splice them together. The car will think a new sensor is installed at which point you should then be able to clear the light. You will have to manually check your brakes for wear every oil change or so...

[minirips2]

I'm not sure if the dealer replaced the sensors or not, but the service indicator didn't come on until after I removed the calipers and removed and reinstalled the rotors after I had them turned and trued. I went back out and ran a scan with the scan tool, and the ABS module showed a rear brake sensor fault. I will order a new sensor, and try that. I'd prefer not to bypass the sensor. Thanks for your quick reply. I'll report back when I've installed the new sensor.

[minirips2]

I ordered a BMW branded rear brake pad sensor and installed it yesterday. I was then able to reset the brake service light. Funny thing is, the old sensor looked fine, and the sensor never contacted the rotor. It was pretty easy to replace. I may have stressed the sensor wire when I hung the caliper to remove the rotor and replace the brake hose.