ABS and ESP lights - Brake pressure sensor fault - Help!


Registered User
I am grateful for all the practical help and advice on here!
I recently had ABS, ESP and flashing glow plug lights with no brake lights. This was cured by fitting a new brake light switch. Since then I have an intermittent problem with the ABS and ESP lights coming on when I brake and remaining on until the car is turned off and on.

I took the car (2003 A6 Avant 1.9 Tdi) to local specialists today. The VAG reader came up with
Brake Pressure Sensor 1 G201 01435

They suggested this could be a new ABS control unit at over £1000. I'm hoping it could be something simpler. Could it be connected to the new brake switch? Is this worth changing?
Any suggestions will be gratefully received!


Registered User
I think I may have cracked it! I reinstalled the brake light switch following the excellent instructions posted on
Since then I have had no ABS or ESP lights.
I think the problem was that the switch was installed so that it took quite a movement of the brake pedal before the rear brake lights came on. Thus the ABS controller was detecting pressure before it got the signal from the brake switch. I have now got the brake lights coming on with the slightest brake pedal movement.

I hope this is useful!


Thats no Moon, Thats a space station!
That helped me alot so thanks for the info as this happened to me this morning when i went to go to work. Quick trip to audi for a new switch followed the guide as per the link and hey presto car is all good again.

Just to say the brake switch i got from Audi today is a revised model so it looked completly different but hopefully works better than the last version.

Also the link to the vwvotex website is very useful as i manged to fit the switch without breaking it as it seems like it might be a little tricky othewise.
Last edited:


Registered User
Thank you very much wilkoa6. Your notes exactly describe my problem and the excellent link to the correct brake pedal switch installation procedure corrected it immediately. I had my ABS control box repaired by Control Units at Cullompton which was absolutely excellent service, but still had "implausible brake pressure" code. This was actually caused by the brake fluid pressure rising before the brake pedal switch told it that anyone had their foot on the brake. It didn't like that, but recalibrating the brake pedal switch to come on just as soon as the pedal is touched completely cured everything. Very useful advice. Thank you.