[shabbaranker]

Hi,

Wondering if anyone has had this happen to them, where you get a service warning on your iDrive that your front pads needs changing in say 900 miles. The following day it tells you they need changing in say 700 miles when there's no way you have done 200 miles in a day and then within a week the red warning comes up to say the service is over due. This has happened to me this week, I've had a look at the pads (on the outside) and there's still a bit on them - I haven't taken the wheel off to look on the inside but my gut tells me its the same....

Has anyone else experienced this?
Cheers

[Billfitz]

The pad sensors are on the inside pads, one in the front, one in the back. It's possible for the inside pads to be toast while the outside is still OK. It happened to me, front and rear.

[shabbaranker]

Thanks probably best for me to pop the wheels off and have a look to see what's going on.

Surely the pads should wear evenly (or as close to even as possible)?

[Billfitz]

They should, but this was my experience:
http://f30.bimmerpost.com/forums/sho....php?t=1471617

[Denny Swift]

I have a very similar situation:

My iDrive is saying that I have 3200 miles left on the front brake pads. I have 50k miles on the car. The front pads have about 6mm of thickness remaining. I removed the front wheels, and the pads are wearing evenly. I have about 6mm on all four front pads. I've got more than half the original thickness remaining so there is no way that I will need pads in 3,200 miles - more like another 50,000 miles. (I got about 85k miles out of my E92 front pads).

So I have two questions:

1st: How does the car sense the remaining thickness? I know there are trip wires, but how does the computer estimate remaining pad life before the the pads are worn anywhere close to the trip wires? Does it actually measure the extension of the pistons or are there two wires - one that trips at about 6mm and one that trips at 3mm?

2nd Question: How do I reset it?

Thanks.

[Billfitz]

The car doesn't sense the remaining thickness. Your iDrive is making an educated guess, based on the age of the car, the mileage and how you drive. Google 'BMW Brake Reset' to find youtube how-to videos.

[shabbaranker]

I read about the iDrive and how it based these settings on how you drive. What worries me is people resetting the brake sensor notification and then ruining not only the pads but the disks along the way.

Either way the wheels are coming off tonight and I'm going to do it the old skool way - have a look rather than rely on technology.

[Billfitz]

You can't reset the brake sensor notification without replacing the sensor. If you replace the sensor but not the pads the new sensor will be immediately tripped. The sensor notification is totally different from and not related to the maintenance message that comes up in the iDrive vehicle information.

[Denny Swift]

Originally Posted by Billfitz

The car doesn't sense the remaining thickness. Your iDrive is making an educated guess, based on the age of the car, the mileage and how you drive. Google 'BMW Brake Reset' to find youtube how-to videos.

Thanks. It's strange that the car would "calculate" 3,200 remaining miles. But now that I think about it, that would take me about 50,000 (I have just under 48,000 - I thought I was closer to 50 when I originally posted). Perhaps there is a 50,000 mile trigger kind of like the oil reminder, which is based on how you drive or 1 year if you don't put many miles on it.

Anyway, I was able to reset it. It would be nice if the reminder said, "Check brakes" rather than "service required", but I guess, checking is service...

[shabbaranker]

Originally Posted by Billfitz

You can't reset the brake sensor notification without replacing the sensor. If you replace the sensor but not the pads the new sensor will be immediately tripped. The sensor notification is totally different from and not related to the maintenance message that comes up in the iDrive vehicle information.

Your right...

I took the tyres off and there's a good 5mm of pad left on both sides of the car. So I tried to reset the warning on the iDrive by holding in the reset button and it said reset unsuccessful.

Is it that BMW expect you to replace the pads with 5mm left hence triggering the sensor? As I would have thought that was a little bit keen (obviously it would depend on driving technique).

Obviously Im going to have to replace the pads and sensor

[Billfitz]

It could be a faulty sensor. The usual trip thickness is 3mm.

[shabbaranker]

Would you be inclined to replace the pads and sensor given they are around the 4mm-5mm mark or just the sensor? I guess its a bit of a chicken and egg situation, if I replace the sensor and reset the pads will need doing soonish anyway and a new sensor would also be required again.

[Billfitz]

With all the work involved in changing the sensor I'd change the pads too. Even after changing the sensor you might not be able to do a reset without an OBD tool to clear fault codes.