its been 30 days since my 2005 A6 showed ESp fault light on my dash. Weird thing is it only happens in the morning at standstill. I would start the car and after a minute the light comes on. Turn the engine off and on again and it does not come back all day long. No other lights.

I have changed the following since I had the code when first light came on. 1. Steering angle sensor, after that it showed low pressure pump so 2. fuel pump and filter was changed, after that high pressure code showed so 3. HFP pump was changed with 4. fuel pressure sensor and 5. fuel pressure module. After that it was fine for couple of days and started coming back but no codes shows in VAG. We hooked up the VAG and waited for the beep in the morning and no code showed for anything. Weird. Everything was checked and cleaned; brake light switch, all sensors (ABS, Wheel sensors, MAP throttle sensor, ABS module connection were cleaned), battery check was done holds constant 12.4 overnight, fuses checked, alternator checked, break fluid checked, trans fluid checked. When light is not on, ABS and ESP performs just fine (tried on gravel road)
Any other suggestions, anyone? It's really annoying that its only happening in the mornings, otherwise car is just fine and runs great with 140k.

 

Its only a matter of time until it will happen every time you start your car. You ABS Sensor is going out. This is a very well documented problem with our cars and with the Bosch sensor's in general. You can replace it to the tune of 1800 plus labor or remove it and send it off to any number of tech's that can repair it and send it back to you.