I drive a A4 2.0 TDi S-Line 05 plate and have been experiencing the following for several months, but what was an occasional issue (once a week) is now daily.

When I start the car it's fine, I can turn the ESP light on and off with no problems.

After I've been driving, sometimes a few minutes, othertimes half an hour, all of a sudden the ESP light comes on and I'm unable to turn it off. Once the engine is turned off and on again, it is okay.

The car feels no different at all to drive when the light is on.

What could it be, any suggestions?

I've read in my manual that this could indicate there is a fault with the ABS, however the brakes also seem the same, no change in operation.

Cheers
Richard

 

is the light solid or flashing? i believe it flashes when you lose traction and the system is activated. if it stays solid without you pressing the button i think it means a system malfunction, which could be the brakes (part of stability/traction control), the anti-slip program, or other parts of the whole ESP system. if it was intermittent and now constant i would guess its a worn/broke sensor that got worse over time.

have you safely tested the system on an empty road? done a hard brake check to activate the ABS? tried to make the tires spin to see if the ESP flashes and cuts engine power like normal?

 

Couldn't log in using facebook this time but managed to get into my original account.

I will try out the breaking etc.

It is a solid light, the last time it was flashing was during the snow but I'll try your suggestions and report back.

Cheers
Richard

 

Testing concluded, braking seems to be the same when there is no ESP light on or when it's consistently on due to malfunction.

I restarted the engine twice on my journey to work this morning so I could test both phases. I also did a wheel spin when the light wasn't on an it flashed.

I'm assuming this indicates that it is not a ABS issue, and that the light coming on more and more over time is the sensor.

 

That's good, seems to be working mechanically but I guess its bad news that its prolly an electrical connection or sensor somewhere. Im not sure if there is a trouble code associated with this light but if you have a good reader or a friend has one, try that. Idk if the cheap ones at AutoZone would work. Then have the dealer or Audi specialist check it out.