DSC, BRAKE light, and temporary loss of control / wobble

[ssyberg]

I'm driving on the highway over the weekend at about 65mph, dead straight, and all of a sudden, for just a blink of an eye, I kind of lose control of the steering. Hard to describe but it felt a little like a single caliper engaged hard and then immediately disengaged, so the car veered slightly to the right. It was a scary feeling, but I didn't have any trouble righting myself immediately. The DSC and BRAKE dash lights went on in conjunction with this and I drove (slowly in the far right lane) for another 2 hours without incident. I stopped once for gas, the lights both went off and then both went back on about 30 minutes later (this time without the scary braking).

I've seen a lot of posts about the DSC and brake lights on, but no one else has reported this weird steering/control issue. One thing I was thinking, I recently replaced brake pads and had a seriously difficult time removing my rusted/seized wheels which I finally got off but some pretty aggressive measures: hitting the tire with the spare, braking hard with the lugs a little loose, and finally slowly letting down the jack with the lugs loose (this is what finally worked). Did I damage something trying to remove the wheels that has now screwed the DSC? Did I mess up the wheel speed sensors? Messed up the alignment (it doesn't feel like it's pulling and goes pretty darn straight with my hands off the wheel)?

I'm going to bring it in the dealer next week for unrelated airbag/recall repairs, I'm hoping I can convince them to pull the brake light codes at the same time.

FWIW - not getting any brake rubbing, I'm always nervous about this so I often feel each wheel for heat right after a drive.

[jclausen]

Check for faults if the yaw pitch sensor is failing, it would think the car is starting to roll for instance activating safety systems. We had a car years ago that did that

[ssyberg]

Check for faults if the yaw pitch sensor is failing, it would think the car is starting to roll for instance activating safety systems. We had a car years ago that did that

This is along the lines of what I was thinking. Is that something that shows up in the normal OBDII scan?

[johnjmurray]

I don't think you can scan that w/out more advanced software like INPA. Try the simple stuff first: make sure the ABS sensors didn't get clobbered when forcing the wheels. Also peak at the sensor rings for corrosion.

[ssyberg]

So I solved this and just wanted to update in case someone else has the same problem. I ended up buying a MAOZUA C110+ (BMW Code Reader) and pulled the following codes:

5E4F (Continuous control)
5E3C (Rotation rate signal)
5E38 (Rotation rate sensor)

The tool itself wasn't specific enough to solve the issue, but with some googling was able to identify the front right ABS sensor as the culprit with a "Speed not plausible" error. My guess is the broken sensor would register a 0 km/h speed for a millisecond and the DSC system would respond by braking hard on the left wheel to try and get the to wheels in sync before realizing the registered speed was not plausible and throwing a code... SO I assumed this just meant the sensor was fried, so I replaced it with a new one from FCPEuro (~$25). It's been a few weeks and haven't had any issues so I think this solved it. It was incredibly easy to replace the sensor, probably took me 20 mins from start to finish.

Hope this helps someone else in this situation!

[Cu292fu]

​

So I solved this and just wanted to update in case someone else has the same problem. I ended up buying a MAOZUA C110+ (BMW Code Reader) and pulled the following codes:

5E4F (Continuous control)
5E3C (Rotation rate signal)
5E38 (Rotation rate sensor)

The tool itself wasn't specific enough to solve the issue, but with some googling was able to identify the front right ABS sensor as the culprit with a "Speed not plausible" error. My guess is the broken sensor would register a 0 km/h speed for a millisecond and the DSC system would respond by braking hard on the left wheel to try and get the to wheels in sync before realizing the registered speed was not plausible and throwing a code... SO I assumed this just meant the sensor was fried, so I replaced it with a new one from FCPEuro (~$25). It's been a few weeks and haven't had any issues so I think this solved it. It was incredibly easy to replace the sensor, probably took me 20 mins from start to finish.

Hope this helps someone else in this situation!

[jclausen]

For that price it would have to be the brake light switch?

[ssyberg]

with some googling was able to identify the front right ABS sensor as the culprit

[SloopJohnB]

​

ReRead the guy's post...right front abs sensor.

[ssyberg]

UPDATE: a few months in and this definitely solved the issue, haven't had a repeat code!