[Eamonn]

Have they actually been replacing the sensor each time? I don't think it needs a software reset, but it'd be easy to do.
Worth getting a VCDS scan to make sure it's not complaining about something more sinister.

 

[Eamonn]

Possibly, I didn't know that you could get pads with sensors attached for these cars. When I did mine, the pads had a gap which I filled with a sensor I bought elsewhere. I have a spare one in the garage.

As for Audi trying it and all being well briefly, they may have reset the fault one way or another, and it simply takes a few minutes for the car to verify the problem is still there. Where are you based by the way?

 

[Eamonn]

Audi only pads is total BS. Same goes for tyres, discs, anything remotely consumable.

 

[Eamonn]

Setting pad thickness shouldn't be a thing, setting the sensor off is mechanical.

If you see metal contacts on the end of the sensor, it's been set off. It's just a wire hidden in a plastic block. As your pads wear down, it wears too until it wears through the wire inside, which sets off the fault. I'll try to find a pic of a new healthy sensor.

 

[Eamonn]

Thanks Eamonn

Sounds like the solution is near .

I really thought that the only sensor was that bit dangling from one of the new pads that plugged into the bit dangling from the car .

It may well be. On the pads can you see any metal dots? If you see a pair of dots it's done for.

This is the sensor I used, it slotted into a notch a top the pad.

Obviously there be a plug on the other end.

 

[Eamonn]

After a quick Google it does look like you can get them built in to the pad, which sounds like what you've got... Bit of a mystery now. Not sure what to recommend.