[fate_f30]

Need some help. I had a warning light come up the other day for low front brake pads. I had brand new brake calipers, rotors, brake pads, and brake pad sensors installed less than 4 months ago. Visual inspection without taking the wheels off shows everything is fine. I tried to reset the senor but it's "unsuccessful". Before I bring this to the dealer and they charge me $500 for a $18 dollar part. Could this be a bad brake pad sensor? Thanks

[Orion4]

Its possible, but usually if the pad sensor / cable is bad, they are bad immediately. Haven't heard of one failing some time after install unless some sort of damage occurred to brake assembly. You could check the sensor connector to the chassis harness to confirm it is completely seated. Other option is take back to whoever did the brake work. Just for clarification, you are not referring to the iDrive Alert for brake service, correct?

[fate_f30]

Originally Posted by Orion4

Its possible, but usually if the pad sensor / cable is bad, they are bad immediately. Haven't heard of one failing some time after install unless some sort of damage occurred to brake assembly. You could check the sensor connector to the chassis harness to confirm it is completely seated. Other option is take back to whoever did the brake work. Just for clarification, you are not referring to the iDrive Alert for brake service, correct?

Hi sorry, Perhaps I should have been more clear. Yes, It's the iDrive warning light. See attached photo.

[Orion4]

In that case, it sounds as if your CBS was not reset for the Front Brake pads when replaced. Were you close to 0 miles left on the front brake wear readout on the iDrive? That is only an estimate based on driving style and miles. If so, the 4 months of driving since the replacement has probably taken your estimated mileage left to 0. CBS does not take any direct input from the pad sensor until it trips and you get the warning on the instrument cluster.

If that is the case, take beck to who ever did your brake work and have them finish the job- reset the Front Brake mileage in the iDrive.

[fate_f30]

Originally Posted by Orion4

In that case, it sounds as if your CBS was not reset for the Front Brake pads when replaced. Were you close to 0 miles left on the front brake wear readout on the iDrive? That is only an estimate based on driving style and miles. If so, the 4 months of driving since the replacement has probably taken your estimated mileage left to 0. CBS does not take any direct input from the pad sensor until it trips and you get the warning on the instrument cluster.

If that is the case, take beck to who ever did your brake work and have them finish the job- reset the Front Brake mileage in the iDrive.

I tried to reset the brakes with the trip reset button but it said "unsuccessful reset". Are you telling me that there's 2 ways of resetting the brake pad indicator? Trip Reset and in the iDrive?

[Orion4]

Is this the sequence you use:
1. Press Stop/Start once (do not/not press the brake or clutch). The instrument cluster will light up
2. The service reminder will pop up. Wait for it to disappear
3. On the bottom left of the instrument cluster is the trip meter, press and hold it. Trip will zero out but keep holding it.
4. Now all service values that can be reset will appear, which you can go through by pressing the trip meter reset button for each value that can be reset (e.g. oil, brake, etc). When you find the value you want to reset, press and hold. It will prompt Reset?
5. Now, press and hold again until the value resets. This should take a few moments not 10's of minutes.
6. Press stop/start to turn off the car.

I have always done my resets via the BT tool software so have not used the above.

[fate_f30]

Hey thanks! I'll give this a try in the morning.

[fate_f30]

Originally Posted by Orion4

Is this the sequence you use:
1. Press Stop/Start once (do not/not press the brake or clutch). The instrument cluster will light up
2. The service reminder will pop up. Wait for it to disappear
3. On the bottom left of the instrument cluster is the trip meter, press and hold it. Trip will zero out but keep holding it.
4. Now all service values that can be reset will appear, which you can go through by pressing the trip meter reset button for each value that can be reset (e.g. oil, brake, etc). When you find the value you want to reset, press and hold. It will prompt Reset?
5. Now, press and hold again until the value resets. This should take a few moments not 10's of minutes.
6. Press stop/start to turn off the car.

I have always done my resets via the BT tool software so have not used the above.

"Reset unsuccessful" At this point I'm thinking it's something loose along the line that may need to be tighten or the senor needs to be completely replaced. Maybe once the computer reaches it's countdown goal the sensor "has" to be replaced as the computer may not recognize it anymore? I'm going to try to drop my car off to my local garage and see if they can troubleshoot it so I don't have to bring it to the stealership. I'll let you know my results.

[bimmer456]

Usually if you get new brakes it is covered for at least 6 months if something goes wrong.

[fate_f30]

Update: Changed out the brake pad sensor this afternoon and that fixed the problem. We are thinking once the brakes were installed the brake sensor was never reset so when it went to zero to created a fault in the CPU and wouldn't allow you to reset it until the brake pad sensor was changed out. Good to know for future reference.

[IAmATeaf]

Isn’t the brake pad sensor one time trip use? Thought once it had been activated it had to be replaced?

[Orion4]

Yes! It mechanically fails once the sensor is worn though be the rotor. If you have the pad replace alert you will need to replace the sensor when you install new pads.

[Garth2079]

Originally Posted by Orion4

Is this the sequence you use:
1. Press Stop/Start once (do not/not press the brake or clutch). The instrument cluster will light up
2. The service reminder will pop up. Wait for it to disappear
3. On the bottom left of the instrument cluster is the trip meter, press and hold it. Trip will zero out but keep holding it.
4. Now all service values that can be reset will appear, which you can go through by pressing the trip meter reset button for each value that can be reset (e.g. oil, brake, etc). When you find the value you want to reset, press and hold. It will prompt Reset?
5. Now, press and hold again until the value resets. This should take a few moments not 10's of minutes.
6. Press stop/start to turn off the car.

I have always done my resets via the BT tool software so have not used the above.

Thanks from me as well. I got the "drive moderately" message yesterday and also assumed it was the wear sensor, since I changed the brake pads about 5,000km ago before the sensor was tripped (and the new ones have 90% remaining). It turns out the message just means "time to check pad wear please". After a CBS reset, it now says I can ignore them for another 50,000km. Which seems like a long time to me but hey.

Perhaps a "Brake pad inspection overdue" warning would be more appropriate than "drive moderately and head straight to your local dealer". It seems a bit too alarmist to me.

You just saved me the hassle of jacking up the car and pulling the wear sensor off only to find it was working correctly.

[Billfitz]

The brake warning system is AFU. Since there are only two sensors and eight pads you can't rely on the sensors to tell you if you need pads. The iDrive estimate of remaining pad life is as accurate as a blind person throwing darts. The only way to know the condition of the pads is to visually examine all of them on a regular basis, say every 10k miles or yearly, whichever comes first. I do mine yearly in the fall as part of my tire rotation ritual, which includes cleaning the insides of the wheels, touching up the paint on the rotor hubs and calipers, checking the differential fluid levels and spraying undercoat on anything that's starting to rust.