What are the lights saying?

[rikdee]

From time to time when driving I get a chime and the illumination of the 'brake' in the lower right of the cluster along with the lighting of the DSC icon mid-cluster. There are no driving or braking issues, there are no stored FCs, the brake fluid level is proper, and the symbols reset after a brief shut off of the ignition. And, it happens only periodically, not with each ignition cycle. Any thoughts?

[Meric]

Maybe alignment? Or speed sensor.

[rikdee]

Maybe alignment? Or speed sensor.

Alignment is perfect, flies as straight as your jet plane! I would think a failing speed sensor would trip an FC, no?

[GT172I]

Are the words red? That response is exactly what happens if you leave the parking brake on when the vehicle is in motion.

Since it's periodic and resets upon stopping (and presumably e-brake application) I'd check that sensor or remember to fully disengage the parking brake. The sensor that determines if the brake is applied is under the boot so really easy to access and check. Pulling up on it past a certain point connects to contacts which completes the circuit activating the light (and alarm if vehicle is moving). The contacts might just be out of alignment... and periodically vibrate/get bumped together.

Ok scratch that, misread your post and missed the DSC light. What color were the lights? I believe they can be yellow/red to indicate different things.

[LivesNearCostco]

I had this problem once. I say it's one of the following, in descending order of likelihood
1) Wheel speed sensor dirty or failing
2) Steering angle sensor failing or needs reset
3) Yaw sensor failing
4) DSC module failing

If you're comfortable getting under the car, you could remove and clean each wheel speed sensor. Each one is held in place by one small bolt. If not comfortable doing this, have a BMW dealer or indie plug in a DIS, GT1, or AutoLogic to read the DSC/ABS codes.

[rikdee]

I had this problem once. I say it's one of the following, in descending order of likelihood
1) Wheel speed sensor dirty or failing
2) Steering angle sensor failing or needs reset
3) Yaw sensor failing
4) DSC module failing

If you're comfortable getting under the car, you could remove and clean each wheel speed sensor. Each one is held in place by one small bolt. If not comfortable doing this, have a BMW dealer or indie plug in a DIS, GT1, or AutoLogic to read the DSC/ABS codes.


I and my friend are quite handy under-car. I might let the dealer read-out any codes and quote the work. Then I'll decide whether I fix it or have it fixed. This is often my method when dealing with unusual malfunctions/repairs. Thanks to all for their responses.

[shadowpuck]

what did you use to read codes? a typical obd-ii code reader might miss anything stored in this system.
are you running non-oem brake fluid, by chance? certain high-performance fluids can cause this behavior, but typically only in really cold temps so depending upon your locale, might not be applicable......just tossing out ideas.

if i run track brake fluid in my zhp and then drive with that fluid in cold ambient temps, i will sometimes get this behavior until the car warms up.

the lights are telling you that portions of the traction control and abs have possibly been disabled due to some fault in the system.

[rikdee]

what did you use to read codes? a typical obd-ii code reader might miss anything stored in this system.
are you running non-oem brake fluid, by chance? certain high-performance fluids can cause this behavior, but typically only in really cold temps so depending upon your locale, might not be applicable......just tossing out ideas.

if i run track brake fluid in my zhp and then drive with that fluid in cold ambient temps, i will sometimes get this behavior until the car warms up.

the lights are telling you that portions of the traction control and abs have possibly been disabled due to some fault in the system.

No, only OEM fluids have ever been used in the car. And yes, an OBDII code reader was used and ABS codes could have not read [part of the discovery]. We're all learning...thanks for your input.

[rikdee]

Dealer said code shows failing DSC pressure sensors (2), a mere $800.00 estimate. The DIY for this isn't too bad but my research shows the problem could be other things despite the pressure sensor code. I think I'll start with cleaning the wheel speed sensors as suggested in post #5 and see what happens. Additionally, I'm not sure if there is any "computer registration" necessary if the pressure sensors are changed. And if so, how in the hell is that done without a diagnostic computer? One thread I read said the ABS pump needed to be cycled after the pressure sensors are replaced. If so, how is that done in the absence of a diagnostic computer?
Thankfully, the lights are not coming on with every ignition cycle having happened maybe two or three times in the past two months. Guess I won't pursue the pressure sensor replacement unless the lights become a regular feature on the instrument cluster....Hmmmm.