[velkin]

2008 328xi, 54Kmiles, 4100miles shown for front pads, 7000miles for rears, Brake fluid due in July. On June 19th my Yellow Brake warning light and a Yellow car on the lift icon turn on. The brake in yellow stays on.

I checked the brake fluid - 1/2 inch over the min. I reset the change fluid interval and right after Check Control came up OK. Next time when starting the car the same Yellow indicators came on.

I searched the forum and could not find a similar condition.

Question: Does anyone know the different conditions for Yellow and Red color on the Brake warning light?

[PINeely]

Brake sensor wire may be hanging loose. How much left on the pads?

[diamondbimmer92]

Originally Posted by velkin

Question: Does anyone know the different conditions for Yellow and Red color on the Brake warning light?

Im pretty sure bmw uses the yellow light as a 'service due soon' light and then presents how many miles until that service... and the red light is for 'service past due' and will show a negative mileage symbol next to it.

[velkin]

diamondbimmer92, it is reasonable that a yellow light would warn about the impending service. The red light would say do it now, like a worn pad sensor.
I wonder if anyone knows how much warning would a yellow indicator give. As I described in the first post, the closest thing in the service intervals was the brake fluid change in July. I reset it and it shows June 2014 now. The yellow BRAKE indicator lights up anyway. The Check Control shows a car on the lift.
The next indicated service is 4,100 miles to the front brakes. It seems like a long warning, as many people would drive 6 months to make the 4.1K.
Perhaps resetting the fluid change is not enough? Perhaps some sensor needs to be reset? I could not find an answer to that on the forum.

[Brad from the OC]

Originally Posted by velkin

diamondbimmer92, it is reasonable that a yellow light would warn about the impending service. The red light would say do it now, like a worn pad sensor.
I wonder if anyone knows how much warning would a yellow indicator give. As I described in the first post, the closest thing in the service intervals was the brake fluid change in July. I reset it and it shows June 2014 now. The yellow BRAKE indicator lights up anyway. The Check Control shows a car on the lift.
The next indicated service is 4,100 miles to the front brakes. It seems like a long warning, as many people would drive 6 months to make the 4.1K.
Perhaps resetting the fluid change is not enough? Perhaps some sensor needs to be reset? I could not find an answer to that on the forum.

Resetting the fluid change will not affect removing the yellow indicator for replacing your front pads. If you really want to remove the yellow warning for the front pads, you need to reset your CBS for the front brake pads. I'm not sure if doing that is effective though. Since the yellow warning has already lit up, from what I understand, the CBS will not reset for the front brake pads. If you reset your CBS before the yellow warning, your CBS will reset to a mileage somewhere around 50K as it thinks you installed new pads. So you probably wouldn't want to do that.

Regarding 4.1K being a long warning, I wouldn't worry too much about that. I don't believe the CBS actually knows how much brake pad thickness you really have. I believe it is merely an estimate based on the expected life of the pads when they were new. I really don't even know if when the light is red meaning to change the pads now, if that means you have minimum pad material left. I think the red light merely indicates that your 4.1K yellow warning is running low.

If you really want to know how much pad thickness you have left, you need to do a visual inspection or have someone else do it for you. The eyes don't lie although a crooked mechanic can lie about the need to replace pads.

I'm convinced that the CBS cannot determine the condition of what it is supposed to monitor. It doesn't know your brake pad thickness, it doesn't know if your cabin air filter is plugged, it doesn't know if your brake fluid is contaminated, it doesn't know if your spark plugs are fouled. It appears that it is nothing much more than an electronic note pad that counts down 2 years for a brake fluid change, 100K for spark plugs, 50K for brake pads, 2 years for cabin air filter, etc.

[velkin]

How does one know that the yellow BRAKE warning is for the front pads. It never told me so. Only a yellow car on the lift when starting an a yellow BRAKE warning constantly on. That is why I figured that it perhaps the fluid change sinse it was close. The pads still have some life left.

[Brad from the OC]

Originally Posted by velkin

How does one know that the yellow BRAKE warning is for the front pads. It never told me so. Only a yellow car on the lift when starting an a yellow BRAKE warning constantly on. That is why I figured that it perhaps the fluid change sinse it was close. The pads still have some life left.

I would use the CBS to verify which brake pads (front or rear) show the earliest mileage before needing to be changed. But in reality, the CBS doesn't really know how much brake pad you have left. When it says 4K life left, it just means it thinks that you wore out the pads based on the expected mileage life of the pad. To determine pad thickness, you need to look at the pads or measure them.

If your brake fluid needed to be changed, you would get a brake fluid service needed indication on your CBS. The brake fluid doesn't give you a warning, just when the 2 years are up since the last fluid change.

[velkin]

I wonder if anyone knows:
OPTION A. BRAKE yellow; car on the lift when starting (this is what I have)

a. Change fluid soon triggers at:

• XX days before due date
• X,XXX miles before change

b. Change pads soon triggers at:

• XX,XXX miles on the odometer
• Less than X,XXX miles on the maintenance computer
• When the sensor triggers
• Other?

c. Inspect something else in the brake system

OPTION B. BRAKE yellow plus, plus... (make your own, I have nothing to show)
OPTION C. BRAKE red (make your own, I have nothing to show)

a. Pad sensor tripped
b. Fluid low
c. Other issue