sjeppell

2006 530xi

I had recently changed my oil and didn't screw the filler cap tight enough. The lack of pressure caused rough idle and stalling. Eventually, the "service engine soon" light came on. I popped the hood and found some oil around the filler cap and realized my mistake. I tightened down the cap and the idle problems disappeared. The service light stayed on. I decided to see if I could reset it using the button for the trip odometer. Mistakenly, I selected to reset the rear brake pad sensor. I had 20k miles left on it. After holding the button down a second time to say " yes" to the reset request, the sensor flipped to -15k and now I get a persistent warning that the rear pads need to be changed. Is there any way to fix this without using a full blown coder?

evolotion

more than likely you need to replace the pad wear sensor, its a two stage affair, it has one bit which sences when the pads have about 6mm left on them and flags a warning and records 0% when the pads have 2 ish mm on them. if you try to reset the break wear indicator while its inbetween these too then you get the result your seeing.

You may then also need diagnostic gear to reset it again properly.

the "service engine soon" message is like an engine managment light, but not as severe, usually will go away after a few cold starts, if not itll need diagnostic gear to reset it.

sjeppell

Thanks for the input. I'm not sure the series of events indicates pad wear. I got no warnings at all prior to mistakenly trying to reset the pad sensor.

evolotion

the sensor hits the first "stage" at say 60% wear. but that doesnt flag up a warning to change it. but if you attempt to reset it at this point it does what you describe. Basically it knows you have attempted a reset but not actually replaced the pads so its in a huff.

Allen

I had the same issue...although not involving the oil filter...but I reset the "light" when it showed 7500 (ish) miles before new pads required...it immediately went to -9000 or -15,000 don't remember which.

People will tell you all about how the sensor works, etc. Obviously, your sensor didn't go from good to bad by changing the oil. The sensors/computer relationship is a weird one...seems to be VERY "touchy" in terms of resetting the brake pad light...very aggravating. APPARENTLY...if you reset your light before it actually turns ON...you get into a "twilight zone" with regards to the computer...you can never tell what the light will do from that point forward...until you actually change the sensor...then all will be fine again.

Here's what I did...raised car, unplugged sensor, insert wire into plug going back to computer, went inside car, reset light again, then removed wire, inserted sensor into plug, all was ok...for a few months. Then the problem came back.