Hi all, this is my first post so I'm hoping someone can help me...

Had my A4 B6 1.9 TDi 130 Avant Sport for nearly 2 years now, and very pleased with way it runs efficiently and reliably even on 190,000 miles! However past month or so I have had problem with ABS & ESP cutting in when not needed.
ESP cuts engine power on nearly every corner I take.
Also under braking (except very light braking) what feels like the ABS cuts in modulating the pedal up and down, but not with a regular rhythmic feeling it's a lot more random, harsher and slower. It is a bit worrying when it happens as the brakes pedal looses its feeling, drops, then comes back up. The brakes never fail, i can always apply them, just with this strange feeling in the pedal and an ABS biting noise from the front brakes.

I ran a VCDS scan with no relevant fault codes appearing under engine or ABS brake system. I thought the most likely culprit would be the wheel speed sensors, so I took all 4 out, cleaned them, replaced, and checked connections, all OK. I checked measuring blocks for the 4 wheel speeds on a log and all read approx. the same speed give 1-2 km/h. Loosing no brake fluid, and I fitted new pads and discs around 3 months ago.


Any one have any idea what could be causing this, as it's making driving very annoying? Worth an ask before I spend £160 on new sensors all around or have to look into the ABS module being at fault.

 

It could be your brake light switch under the dash. My ESP went on due to the broken switch. My brake lights never went on unless applied although the switch was still causing ESP problems.