This is not another infamous flashing ABS how do I fix it question. However it is unique. 2002 a-4 abs 3 light deal comes on ONLY when I turn on headlights. If I turn on running/parking lights, it's ok. As soon as I go one more click to headlights, DING.....FLASH.....FLASH.... Ever hear of that one? It will do it 3 out of 5 times after starting car. They never come on after a few minutes of driving.

 

I believe you might have aftermarket HID headlights on your A4, if that's the case the electronic module is mounted very close to your ABS module and is causing interference, this is not a proven problem but as soon as they move their elctronic module for the HID headlights the problem goes away. There's a thread here and one in Audizine, here I think Pa4l knows how to move it but I'm not 100% sure.

 

i believe its the passenger headlight hid ballast thats can be moved. Although if u avoid turning on your headlights while in reverse i notice the problem tends to stop. i always turn on my lights either right when i turn on the car oorrr once im out the drive way and in drive.