Traction Control Issue... Need Help
Thread Starter
Intermediate
Joined: Jun 2004
Posts: 36
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From: Warr Acres OK
Traction Control Issue... Need Help
I am trying to help someone with a 05 C6 A4 that has different size wheels/tires than stock. The research I've done is that with the stock wheels/tires, the rears are 1.5" taller than the fronts. With the combo he's running now, the rears are .2" smaller than the fronts. This is causing the Traction Control to activate when at highway speeds. Right now, he is putting the car in Comp Mode everytime he starts the car to avoid the problem. Is there any fix for this? I have HP Tuners, but before I spend the money to license the car, I need to see if there is a fix for this in the PCM. My gut feeling is this is a BCM issue or some other module that is sensing the wheel speed sensors, thinking traction is lost because the rear wheels are now truning faster than the fronts.
rear smaller than fronts?
Thread Starter
Intermediate
Joined: Jun 2004
Posts: 36
Likes: 0
From: Warr Acres OK
The car has 275-35-18 in front and 315-30-18 in the rear so they don't look noticably smaller, but when the TC system is expecting a 1.5" taller tire in the rear and it is seeing a .2" smaller tire, it apparently is enough to cause a problem.
The system isn't set up to work correctly without the proper stagger in tire diameter. Change the tires.
