[Remo_Valentino]

The Red "BRAKE" warning light recently illuminated on the dashboard, accompanied by the "car on lift" light. Message center details state "Brake Pads have worn to the minimum thickness. Have the pads replaced by the nearest BMW center."

When in I go into the Service Required menu, however, it says the rear brake pads are "OK" with replacement due in 6,000 miles. Front brake pads are "OK" and due in 36,000 miles.

It seems to me that these messages are conflicting. Anyone know what is going on here? Thanks.

[Demz760]

Also replace the brake sensors.

[Efthreeoh]

Okay, so Abnob doesn't know what he is talking about. I'm going to address what he said. The system uses dual stage consumable brake pad sensors to (a) help estimate the predicted amount of pad life remaining on the brake pads, and (b) notify the driver when the pads have reached minimum thickness and require replacement. If the brake system has not been properly maintained, meaning the pads and sensors are not replaced together and the system properly reset, the system can get out of whack. The CBS uses an algorithm that calculates brake pad wear on a pre-determined standard. Once the pad wear sensors reach their first stage (a wire loop in the sensor breaks from rubbing on the brake rotor), the CBS then has a real-use data point for wear rate. The CBS can then better predict the estimated miles left in the pads. These calculations are done independently for each axle set of brakes. When the second loop of wire in the sensor breaks, then the red brake light icon (the same one used when the parking brake is pulled up) lights up and stays lit and the CBS provides audible and visual notification that brake service is due.

While Abnob states you can simply reset the CBS notifications, that is really not true with the brake monitoring system, because the system relies on the pad wear sensors sensing when the pads are worn out. As I previously stated, resetting the pad wear indicator without replacing the pads and wear sensor (there is just one sensor per axle) the notification will not go away; there are many threads on that subject. For the other CBS service items (like engine oil) you can ignore the system and simply reset the menu items, but it's kind of stupid to do so.

So your case is unusual. I don't have experience with the I-drive system, but lots of experience with the CBS brake monitor system. If you do not know the service history of your car, then it is possible that previous owners have not properly maintained the brake system (i.e. have tied off the sensors or left old sensors in the system and shorted the wires to falsely reset the indicator). Since the front brakes show 6,000 miles left, you should look at them first and measure the pad thickness. The minimum pad thickness is 3.7MM for both front and rear brakes. Being the rear brakes show 36,000 miles left, it would seem you are due just for front brake service. I always replace pads, disks and the sensor as a set.

[Dapper93]

Amazing explanation, EfThreeOh. Similar error that OP described happened to me. Picked up a new-to-me E90 2 weeks ago, iDrive System Check stated F/R brake replacement in 12/15K KMs, and this morning I got the same message described.

Originally Posted by Remo_Valentino

"Brake Pads have worn to the minimum thickness. Have the pads replaced by the nearest BMW center."

Only thing different was that the message goes away when I park/shut off the car. Thought that was odd, since I wanted to park and then check the iDrive to confirm which axle was tripped, but it still said all was OK.

I'll be getting some new hardware and checking the pads although probably prudent to replace the pads/discs anyways.

Cheers

[Bimmer_Bro]

Originally Posted by Dapper93

Amazing explanation, EfThreeOh. Similar error that OP described happened to me. Picked up a new-to-me E90 2 weeks ago, iDrive System Check stated F/R brake replacement in 12/15K KMs, and this morning I got the same message described.

Only thing different was that the message goes away when I park/shut off the car. Thought that was odd, since I wanted to park and then check the iDrive to confirm which axle was tripped, but it still said all was OK.

I'll be getting some new hardware and checking the pads although probably prudent to replace the pads/discs anyways.

Cheers

I hate the brake sensors on these cars. They get tripped when there is still 40-50% pad left. There is one for the front and one on the rear. Last time I did my brakes I just spliced the wires and closed the loop. I check my own brakes regularly anyway so I didn't need sensors.

[Dapper93]

I hear that's a popular opinion/solution. I'd probably get tired of the sensors eventually but I think I'll ride it out for a bit.

I think I might have mucked it up, in hindsight. Car has coils and I was raising them up for the winter. I was a little *ahem* generous with the brake parts cleaner and the degreaser to get the road muck off. Thinking that might have done something for the sensor but now the front pads are squealing so it could just be coincidence.

[Wolf 335]

You guys still use these sensors? Mine have been cut and wires connected since the first time a brake message popped up.

[IllSic_Design]

Originally Posted by Wolf 335

You guys till use these sensors? Mine have been cut and wires connected since the first time a brake message popped up.

Same, right when the message came on I cut the sensor and soldered the wires. Never have to worry about it again

[dtatch]

hey peeps
have cut an joined my brake sensors but I have an issue with the reset of the brake warning message not showing a miles left so the warning does not go away... any idea's

[ky0u]

Originally Posted by dtatch

hey peeps
have cut an joined my brake sensors but I have an issue with the reset of the brake warning message not showing a miles left so the warning does not go away... any idea's

Have you tried reseting it using the BC menu?

[dtatch]

yes thanks.
thats where i get the reset but it doesnt include the miles to next change.
is it that the system algorithms are looking for a new sensor to indicate a new session??

[dtatch]

Originally Posted by ky0u

Have you tried reseting it using the BC menu?

yes thanks.
thats where i get the reset but it doesnt include the miles to next change.
is it that the system algorithms are looking for a new sensor to indicate a new session??

[frodmyster]

Did you fix this?

[frodmyster]

Mine won't reset. Stay on at the miles to next change is -------- can anyone please help