Hi, i just had my brake pads and rotors changed on a 328ci, but the brake pads warning lamp won't go away. i didn't change the sensors and i'm wondering if this has anything to do with it. the mechanic said i need to break-in the new brakes before the light goes away. does anyone know if this is true?

thanks.

Hi, i just had my brake pads and rotors changed on a 328ci, but the brake pads warning lamp won't go away. i didn't change the sensors and i'm wondering if this has anything to do with it. the mechanic said i need to break-in the new brakes before the light goes away. does anyone know if this is true?

thanks.


Pop the cluster and take the bulb out, those sensors are useless. By the time that light goes on it's too late for your rotors.

Was the light on before the brake work? If so you have to replace the sensors (left front & right rear). Once the sensors are replaced turn the key to position 2 (ignition on), wait 30-45 seconds, then turn the key off.

Pop the cluster and take the bulb out, those sensors are useless. By the time that light goes on it's too late for your rotors.
The sensors are useful. When they trip you have roughly 2mm of pad left, or enough for about 1000mi of ordinary street driving.

BMW rotors seldom last for more than one set of OE pads. The total allowable wear is only 2mm (1mm/side) and even a soft set of OE pads will usually wear the rotors down that much. So waiting for the light doesn't decrease the life of the rotors.

A better approach than pulling the bulb is to simply tie wrap up a good pair of sensors to the brake line where they can't get hung up on anything. The next owner can install the sensors if they want and everything will work as expected.

Mine have been tied out of the way since I started tracking the car. Partly because I'll be checking the pads for wear at least every month or so and partly because I don't want to risk damaging the sensors every time I change pads. I go through 2-3 sets of pads & rotors each track season.

Once the circit in the sensors are tripped you have to replace with new ones from the dealer, approx $12 each (theres two, one on the front and one on the back).

The sensor definately needs to be replaced.
Once the sensor is replaced, and the light still doesn't go off, the ignition must be turned to position 2 (position right before cranking the car to start), until the light has gone off.

I know this, as I replaced my brakes about 3 weeks ago. I probably wouldn't go to that mechanic anymore. Don't listen to people saying the sensors are worthless either. It's good to have them, as in my case, I hadn't noticed any deterioration in my braking, but a while after the light came on, I noticed it. The sensor did it's job.

Thanks everyone for your input. A mechanic from the dealership told me to change both front and back sensors which I'll do soon.

If you only got the front brakes done just change the front sensor, unless you're going the tie it out of the way route then might as well do em both.
~CHUBBIE~

Yeah, if you replaced the front brakes, only replace the front sensor, and then turn the key to position 2, and wait for the brake pad light to go off.

If you need rear brakes, replacing the sensor won't do anything, as the new sensor will become triggered as well. It'll be just a waste of money. What was the mechanic thinking? Surely he didn't mean to say that, or maybe he thought you replaced the rear brakes as well (benefit of doubt).