# Brakes engage when cornering



## Wilber01 (Dec 18, 2014)

HELP!!

This is my first post and thank you for anyone who can advise on this mystery problem. I have a A4 2009 saloon, I noticed a cpl of weeks ago when cornering my transaction light flickers and the brakes engage and what feels like loss of power to the wheel in cornering. Then it was clear itself and drive normally until the next corner. It's been in the garage and the wheel sensors have been checked, all clear, all 4 wheels have been aligned, and it's been on Audi's machine and it DOESNT through any codes up at all! Not one. The mechanic is now thinking that it could be the YAW unit under the seat! But isn't sure. Has this happened to anyone before? Like I say, there are no lights on the dash at all until I corner and the transaction light flickers and the brakes sound awful, like a grinding noise.

Thankyou


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## Mr_Rally (May 3, 2003)

Just how agressive are you driving this car?


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## Wilber01 (Dec 18, 2014)

Mr_Rally said:


> Just how agressive are you driving this car?


Hello, not aggressive at all as I have my daughter in the car! The brakes engage at 10mph + on any camber of cornering!


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## Mr_Rally (May 3, 2003)

It does sound like a sensor issue. I'm no expert on that system. The accelerometer (yaw sensor) may not be calibrated correctly. Does the problem occur when cornering only to one side and not the other?


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## Wilber01 (Dec 18, 2014)

Mr_Rally said:


> It does sound like a sensor issue. I'm no expert on that system. The accelerometer (yaw sensor) may not be calibrated correctly. Does the problem occur when cornering only to one side and not the other?


Thanks for the reply, no it happens on both corners


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## jimbbski (Jun 3, 2007)

I'm not familiar with your car but try to see if you can disable the stability control system by pulling it's fuse.
It that works to cure your problem then I would have to agree that a sensor is the problem.
It could be calibrated wrong or is could be just loose and sending of readings that indicate more aggressive cornering then is actually occurring.


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## Wilber01 (Dec 18, 2014)

It's recently had a new steering rack fitted and that's been calibrated. I'm taking the car to another garage this morning so I'll post what the outcome is/was. I'm pretty sure it's a sensor issue so we'll see what this garage says today. Cheers


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## racerpoet (Apr 20, 2013)

So what was it? Was it the yaw sensor?


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## Wilber01 (Dec 18, 2014)

Still not fixed yet. Got to go back in new year so they can check the settings or something on the yaw sensor! Said something about re calibrating the unit! Hope it doesn't need a new yaw sensor as there not cheap!


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## petethepug (May 25, 2001)

VCDS should be picking up a code or the tech that replaced the rack allowed the ABS control module to lose it's programing. Is this an indie shop? Do they have adequate equipment to get the info they need?


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## Wilber01 (Dec 18, 2014)

Yes it's a indie shop. They've told me that a tech came from the audi garage with the top range of computer systems. No code is showing. When they put the machine on and drive the car the transaction light is on but the car doesn't do the problem when cornering! Makes me look a lier!! Hahaha. But as soon as they unhook the computer it starts with the problem again! Someone said its more than likely the yaw sensor. But this has only started when it came out of the garage from having a new steering rack fitted! It looks like the techs have made a mistake somewhere or broken something when changing the racks.


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## petethepug (May 25, 2001)

This is good news. It shows that the ABS module needs to be read and diagnosed at the dealership, by the dealer. Obviously if there's no issues when the car has Audi's diagnostic connected, the ABS needs to be read then verified it's not shifted over to thinking it's running a manual vs. auto trans or visa versa. 

The indy shop needs to pay to have the dealer see what's going on, period. Don't let them try to pull the empathy game with you that "they're losing money on fixing your car". $40 more an hour diagnosed and fixed correctly the 1st time is less expensive than letting an indy shop experiment with your car.


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