Yellow "BRAKE" warning light - what's the cause?

[str8shot]

I've gotten the yellow "BRAKE" warning light in the cluster, along with a picture of the car on a lift, a dozen or so times in the last two weeks.

It eventually goes away, but seems to come back just as quickly.

I know you lose hill-assist when it's illuminated. Can anyone tell me what triggers the fault?

[MZWIE]

Worn pads. Bad pad wear sensor.

[Focusedintntions]

It means just that...the hill hold feature is disabled. Generally i've only see that when doing very hard drive and the brakes are getting very hot. If you're getting it during normal driving conditions you should take your car to get it checked out.

[str8shot]

Originally Posted by Focusedintntions

It means just that...the hill hold feature is disabled. Generally i've only see that when doing very hard drive and the brakes are getting very hot. If you're getting it during normal driving conditions you should take your car to get it checked out.

How does the wear sensor work? Normally open, then closed by the rotor? Or normally closed, then burned through to trigger?

I'm thinking there might be a build up of pad material on the sensor cause a false positive.

Can't imagine the pads are gone already - I've only got 15k on them (few auto-x's, the rest street and 40% highway).

[Focusedintntions]

The pad wear sensor is a closed loop...when it burns through it'll open the circuit and cause a red warning on your dash showing it worn. The work around if you don't want to use pad sensors anymore is to strip the wires off the old one and splice them together...then wrap with a bit of electrical tape.

The sensor itself is just plastic and the wire is in it. So pad material building up on won't affect it. If there was an issue with the sensor I'd guess a red warning lamp would show up. What's your fluid level at? If your pads are getting worn maybe fluid is starting to get a bit low as more fluid goes into the line. Might just need a splash of fluid in there.

FYI a few auto-x's and 15k of mileage could be enough to wear pads out. Specially on the back where it pulls double duty due the "e-diff" action.

[verymau]

Hi Guys,

I have a similar problem. I have a used(from 2009) 120d coupe that I bought back in March. The warning light for the brake fluid is red. Does this mean I need to go to the garage straight away or is this just based on the time that the mechanic put there? The brakes look normal to me.

Also, should I do it with BMW or in another garage is fine? All the servicing has been done with BMW so far.

Cheers
Jorge

[str8shot]

Originally Posted by verymau

Hi Guys,

I have a similar problem. I have a used(from 2009) 120d coupe that I bought back in March. The warning light for the brake fluid is red. Does this mean I need to go to the garage straight away or is this just based on the time that the mechanic put there? The brakes look normal to me.

Also, should I do it with BMW or in another garage is fine? All the servicing has been done with BMW so far.

Cheers
Jorge

For what it's worth - I now have the red brake indicator, instead of yellow; and it's permanently on. My fluid level is perfect. I think I burned through a sensor. Gonna pull the right wheels tomorrow to check.

[wespar]

I had this very problem after a performance alignment done by BMW gone awry (resulting in the steering wheel not being centered when going straight) & BMW re-aligning it fixed the issue. Go figure.