Hi,

My 5 year-old, so far very trustful A4 Quattro started giving me trouble:

1. When I break, and I am almost stopped (10-15 km.h) the break pedal suddenly starts pumping as the wheels would be slipping and the car stops promptly (like breaks would jam). When I release teh break pedal I can hear a 1-2 second buzzing noise.

2. After driving wiht high speed, or uphill on a hot day I hear a scary noise from the power-train, like fanblades hitting an obstacle in their way.

Could anyone, please, give me some hint?

 

sounds like you need to have a look at the condition of the pads/rotors, the peddle does pulse on breaking with ABS that's normal

 

Hi Dave,

Thank you for the reply. The discs and the pads were changed a year ago (approx. 20000km ago).

I should have mentioned that I can hear the ABS working (buzzing) below 6km/h, when it should actually turn off itself. This is when the sudden decelaration happens, as well. Where could I find a description of the Audi ABS system from other source than the Service Manual? Similarly where could I find a description of the Audi clutch or the entire transmission chain (for quattro)?

Best regards,

Emil.

 

any dummy lights on??

 

Thanks. No lights on. I took it to the autoclub and they did not get any fault from the OBD. The breaks are all good - pads and discs. The problem is that the break james when I decelerate to below 5-6km/h. I think this is when the ABS suppose to deactivate itself.

Ist there any electronics control box for the ABS?
How could I re-initialize this?
How could I clean the ABS sensors?

 

its definatelty one of your ABS sensors...same thing happened to my car and its just weird. I got a new sensor put in and everything went back to normal, the only thing that im questioning is my ABS and BRAKE dummy lights came on.

 

Thanks a lot. This is a much better use than having to change the pump. How did you find out which sensor is deffective? Was it a great deal for yourself to change the sensor? Does it require any "synchronization" afterwards or any other magic?