Hello, I had an emergency and was forced to get front tires bigger than stock. For a little while the car drove fine, then the ABS light turned on (scan told of rear wheel sensors). I erased it with Ficom. I let the car sit for two weeks and after climbing to about 10mph, ESC flashes, the brakes stick (discs heat up) and throttle will not respond further. I rebuilt the caliper, replaced discs and pads but the issue persists.

Is the problem the wrong tire size or something else?

Please help me if you can. Any ideas would be greatly appreciated.


Also, if you know how to resolve this issue but require payment, we could arrange something through paypal.

Different tyre sizes tell the ABS /ESP sensor that the wheels are turning with different speeds which the system then ries to correct. Guess how ? By braking the wheel that turns too fast, which is the smaller one. So yes, the wrong tyres are the most likely reason for the problem.

New correct size tyres.

I replaced the rear tires with the same size as the front and the problem persists. I touched both front brake discs and it seems only the passenger side is heating and the grinding noise is coming from there.

Any other ideas? Thanks again for your time.

First check you have the correct size tyres as your first and last post contradict each other next 're look at both front calipers make sure they slide correctly on it's pins that the pads are not a tight fit on the guides and everything is seated correctly etc?

The pins slide correctly and the wheel turns freely. The car runs and brakes normally at low speeds (~ <10mph). As for tire size, it's not stock: 215/45ZR17 87W. I don't have money to change all four tires.


I would like to verify the rear wheel speed sensor but am having trouble finding a guide on removing it. Does anyone have a link to information on that?

Thanks again.

Forget the tyre sizes.. that's a complete red herring. The system won't complain as long as the wheels are going round.

It doesn't care about the relative rotation between the front and rear axles either.. it doesn't even care about the relative rotation between wheels on the same axle (although if you have different size tyres *on the same axle* that probably contravenes your local vehicle regulations. Different size tyres front to rear is usually permissible.

If one wheel is getting hotter than the others and you're *absolutely sure* the brake isn't binding (jack it up, spin it by hand) then the problem is almost certainly (as above) that the car ESC is braking that particular wheel. Unless your ESC is being a bit random, that suggests that the sensor on that wheel has simply packed up.

Swap the left sensor to the right of the car (and vice-versa) and see if the problem moves with the sensor or whether the problem persists on the same corner. A new sensor (if that's the cause) isn't too dear.


Ralf S.