I have a 1997 a4 tdi avant auto, and my ABS light remains on along with the red brake warning light flashing continuously.

My local garage has identified a problem with the nearside wheel sensor and replaced it with a sensor taken from an audi 100.

Now the ABS light remains on but it does dim after a couple of seconds - and the ABS is functioning fine. Unfortunately this won't help my car pass its impending MOT!

My local garage is at a loss what to do next! Could someone please advise. Thanks