Good evening all,

Have a Polo in the workshop today with an interesting fault.
We have a glow plug light flashing and a fault code of

"16955/P0571/001393 - Brake Light Switch (F): Implausible Signal"

i have not looked at the vehicle myself but an interesting conversation between me and my technician proves he has checked all the basics.

The vehicle has been presented to us with a selection of brake light switches, all fitted by previous garages, we now have a genuine new switch fitted! The brake lights work and we can see that pins 1 and 4 are correct.

Pins 2 and 3 are for the signal feed back to the ECU. Both are +ve untill the brake pedal is pressed, then one of the pins drops to -ve... So far, the pedal switch seems to work?

He has also checked and load tested the relevent wire back to the ECU with both ends disconnected and wiring seems ok with no shorts to +ve or -ve...

im going to have a look over it tomorrow morning just incase there is something he has missed, although i am very confident in his ability to carry out the above tests, we all make mistakes every so often..

the other thing got me thinking is the coding of the ecu.

Is there something we are missing?

Kris