Audi Rotation Rate Sensor

audi
a6

#1

I have an '02 Audi A-6 3.0 Quattro with 75,000 miles. I have a major problem with the anti-lock break system. It started with the ABS light coming on, then led to the anti-lock breaks kicking on intermittently at random moments while driving, with my foot on the gas. This has went on for the past few years, sometimes not happening for months. I’ve had it in to the dealer a number of times to get this checked out. They could not get the car to replicate the problem, suggested replacing the YAW/rotation rate sensor but could not guarantee it would fix the problem. The breaks kicked in at 60 mph a couple months ago, pulling me off the road and making me skid to a stop and pulled to the right. Luckily, I was not hurt, got the car in right away and had the sensor replaced. Now, the ABS light just started coming back on again at random moments. I’m scared for my life in this car b/c it is not safe. I’ve tried getting help from Audi of America on this and they have denied my requests, saying it was not under warranty. You would think they would go out of their way to help with this very dangerous problem. Everyone is telling me to sell the car right away, but it’s a couple months from being payed off and I just want this fixed! Any suggestions???


#2

If I owned a car in which the brakes applied themselves, I wouldn’t drive it one day, much less several years.

I’m not aware of anything in the ABS system which could make the brakes apply themselves, but then, I’m not an Audi expert. Maybe we have a new category: Unintended Deceleration.

Have you contacted the NHTSA? National Highway Traffic Safety Administration.

If not, I suggest you do so.


#3

I think in the event of an accident that can be traced to loss of control due to erratic braking a lawyer would make short work of both you (because you had prior knowledge of the problem) and to a much lesser degree the Dealer that made the half-a**** repair. By continuing to drive this car you are playing with fire. Selling this car without telling the buyer about this problem should be considered criminal.


#4

It’s not the ABS system applying the brakes, it’s the stability control system commanding the ABS to apply the brakes on specific wheels. This system’s purpose is to try and prevent skids and such. Apparently because and a faulty sensor or module or wiring, it thinks the vehicle is going into a skid and is trying to bring it out of it.
I don’t know about the Audi, but on most cars with stability control systems, you can turn the system off by pressing a button every time you start the car. I would do that until this is resolved.


#5

Thanks, tardis. I never thought of that. It makes sense now.

Stability control, indeed.

Doesn’t seem to stable to me. Seems like something Audi would be concerned about, regardless of the age of the vehicle.


#6

From your description of what is happening, I also agree that it is most likely the stability control/traction control system that is having an issue.

I would recommend replacing the two rear wheel speed sensors, and have them inspect the reluctor rings back there for any damage.

Since its an AWD car, have you been changing the 4 tires all at the same time?
Have they been getting rotated from front to rear on a regular basis?
Do you have aftermarket rims and tires, or different size tires than what originally came stock on the car?
Has the car ever been in an accident?

Start with the rear wheel speed sensors, or all 4 if you can afford it.
Chances are one or more of them might be having an issue, and that is causing the car to think its starting to lose control, which leads to the crazy braking.

BC.


#7

Be aware that these cars (like many) have a yaw rate sensor. This is basically like a gyroscope (only solid state) that senses any changes in velocity (speed and direction) that the car make experience. The system compares this input to the wheel speed inputs and the steering wheel angle sensor. If all don’t agree, then it assumes that the car is out of control and it applies brakes to turn the car back in the correct direction. Since it is causing a skid, it is reasonable to conclude that the problem is the yaw sensor or the steering angle sensor (or the control module or wiring). An issue with a wheel speed sensor wouldn’t cause a skid. At most it would reduce power or braking.


#8

It sounds like Tardis has the same educated guess that the dealer concluded. If it were my car there’s no way I’d postpone getting it fixed while searching for a guaranteed fix. I’d go with the yaw sensor.


#9

Folks, isn’t it wonderful to know that we may soon be mandated to have these systems on all our cars? I’ve made no secret of the fact that I thought this system was a problem waiting to happen. Anything that can apply your brakes for you without your input is subject to dangerous malfunctions. Having read this post, I can finally rest my case.


#10

Thanks for your post. Yes, all 4 tires were replaced last year, have been rotated, were not aftermarket or a different size, and the cars never been in an accident.
I believe the next step for me is to get the rear wheel speed sensors replaced.


#11

I had the YAW/rotation rate sensor (same thing) recently replaced…and the ESP light started flashing back on at random moments a week after it was replaced, which is how this problem started, with the light coming on at random moments, then followed by the breaks kicking in for seconds while the light flashed on, and progressing to the skidding off the road @ 60 mph incident.
I turn the ESP off every time I start the car, but with this system malfunctioning, I have no confidence that hitting the ESP button is actually turning the system off.
I will be contacting the NHTSA and have absolutely no confidence in Audi anymore.
When I am broke, need a way to work, can’t sell the car and therefore need money to pay for endless tries at fixing this problem, I have no choice but to drive the car. Trust me, I have a death grip on the wheel while driving, but what else can I do???