[jlE90]

My brake light came on recently while i was exiting from a freeway. So i got it checked and it turns out my rear pads are out. I've purchased 1 set of rear pads and 1 sensor. I did the install myself and it was basically a piece of cake. Until i tried to start the car, the brake and service light was still on. i've tried resetting it with http://www.e90post.com/forums/showthread.php?t=360706 and once i got to the RED rear brakes reset, i see -40miles. i'v held reset and after waiting for the clock to go away, it still says -40miles. i also took the car for a 10mile drive and still no luck. Is there another way to reset? the dam dealers over here in san francisco wont reset unless i've done the brake job there. my car is at 57k miles and i have no warranty

[ENINTY]

Humm... Maybe the CBS didn't reset correctly because you restarted the car before you reset the service indicator. Maybe you should try to unplug the sensor for a few mintues, then re-connect it, then re-set the CBS for the rear brakes, without first starting the car.

This is just a guess on my part and when I read it it doesn't make much sense but I'm thinking redoing the process of adding a new sensor back in the system will trick it into thinking you just did the brake service. When I did my brakes, I reset the service indicator before I started the engine and never had a problem.

Or see if you can find a local BMW owner that has the BT scan tool and reset the CBS from there.

[jlE90]

after i installed the new sensor my car was only in the on position just to get into the service menu. and ive tried to start to car hoping that it will register the new sensor but no luck.

also would even plugging the sensor in the harness but not in the brake pad worth it? i mean if the sensor never grinds down, it will never wear out (so no need to replace later) all the sensor seem like is a ceramic piece with 2 copper wires inside, and a small bridge continuing the current

any suggestions would be appreciated

[ENINTY]

Not sure why you'd not want to use the sensor. If you don't, then there is no way to monitor the pad use except for a periodic visual inspection. The sensor is plastic and has two loops of wire in it so the CBS can estimate brake pad wear. The sensor is $20, which is much cheaper than the time it takes to periodically look at the pads to check for wear.

[jlE90]

well i've tried 3 sensors, 2 aftermarket n 1 dealer and same thing is happening. wont let me reset the dam brake lights n yes aftermarket is cheap but quality is poor and sizing is a little bit off. dealer's basically the same but they wont back up their product. they wont let me exchange if i even mounted it, so f*@# the dealer

[ENINTY]

So I re-read your original post. I didn't read correctly the first time and didn't understand that the pad wear indicator light is still on; I thought just the CBS service indicator was on. So now I'm concerned you may have damaged the connector at wiring harness that goes to the body (behind the fenderwell lining). The circuit is simple. If the circuit is open (i.e. unable to pass electrical current) then the pad warning light stays lit, which is the condition when the sensor is worn out. When the circuit is closed (i.e. able to pass electrical current) the light goes off. If you've damaged the wiring harness connector then the circuit will not close even with a new sensor.

Check the circuit by using the old pad sensor (if you still have it). Take the old sensor and cutoff the head of it. Strip off the wire coating from the ends of both wires about an inch and twist them together. The modified sensor wire will then look like a closed circuit to the system. The plug in the old, modified sensor into the body harness and see if the light goes out. If it doesn't then I think the connector at the body side of the harness is damaged and the wire inside the molded connector is broken.

You can test this as well, but you'll need a volt meter to test the continuity of the wire from in front of (before) the body-side connector to behind (after) the body-side connector (i.e. the sensor wire). Take a small diaper pin and pierce the wire coating to get contact with the metal wire inside it on the body-side of the wire going into the connector. Then break the loop you made with the old sensor and attach the volt meter (set to continuity mode) to the pin and to the metal wire end on the old sensor and see if there is continuity in the wire through the connector. Do this for both wires. Make sure you keep the polarity correct so that you are not getting a false reading of un-continuity in the wire you are testing.

If you don’t get continuity then the connector in the harness is damaged and you’ll have to fix it with a new water-proof connector.

[jlE90]

if i do have a faulty harness can i just eliminate the harness and sensor? this brake sensor is causing more headaches then its worth. regret not getting it done in the dealership.

[govtec]

Originally Posted by jlE90

if i do have a faulty harness can i just eliminate the harness and sensor? this brake sensor is causing more headaches then its worth. regret not getting it done in the dealership.

Have you resolved your issue yet? Did you have any issues taking the old brake pads apart? I'll be changing my front brake pads soon and hopefully I won't have this same issue.

[jlE90]

nope still didnt fix it, i've tried ENINTY's way. I checked the harness with a volt meter when the car is in the on position and found that theres a current. I've tried bridging it with a paperclip but that didnt work either. I am about to take it to the dealer next week and hope its cheap since im out of warranty. if i were you, sacrifice your sensor indication and yank both your sensors out before it does wear down.

[jlE90]

i just called bmw and they want 198$ to diagnostic and 85$ to reset

[ENINTY]

I'm stumped now. Having the dealer look at it might be the best thing.

[govtec]

Ouch!!! Have you tried contacting a local reputable indy shop?

[pdav]

FYI, to any guys that are looking for "cheap" brake pad sensors, try rockauto.com and search by part number. I just bought rear and front with shipping for $22 listed with OEM part numbers. so i am pretty sure they will be identical as the dealer ones.

[bmw325i]

Originally Posted by jlE90

nope still didnt fix it, i've tried ENINTY's way. I checked the harness with a volt meter when the car is in the on position and found that theres a current. I've tried bridging it with a paperclip but that didnt work either. I am about to take it to the dealer next week and hope its cheap since im out of warranty. if i were you, sacrifice your sensor indication and yank both your sensors out before it does wear down.

Even if the sensor never gets worn down the warning light will stay on unless you replace the sensors.

[juice13]

Originally Posted by pdav

FYI, to any guys that are looking for "cheap" brake pad sensors, try rockauto.com and search by part number. I just bought rear and front with shipping for $22 listed with OEM part numbers. so i am pretty sure they will be identical as the dealer ones.

Did you install the very non-OEM sensors yet? I'd like to try them as well.

[Xander]

I'm having issues with mine too.

Magically at 70K the "brake" light on the dash went to RED. It was for fronts AND rears at the exact same time. The pads and sensors are fine. I feel like there is programming in the car that won't allow you to "ghetto" reset the warning at a certain point. My pads have a TON of life left (about 3/8" per pad).

I'm thinking of trying another set of Sensors at $22, but still WTF. I know on my VWs in the past I could use a wire splicer to connect the 2 and be done with it, however I was under the impression that we have 2 step sensors where the first part wears down to the yelow "brake" light to have you be aware that they are getting close, but not quite worn out yet. If that is the case there should be 3 or 4 wires to attach. I am going to try and take one of them out and see.