Had the same problem on my VW Passat 2002 1.9TDI Estate...glow plug light flashes and the ''ENGINE WORKSHOP!'' light comes on! These lights come on when a fault is detected by the engine management system (on board computer). The brake lights come on automatically and stay 'ON' as a safety feature, as long as the glow light stays on i.e. 'fault condition'. When the fault disappears or is attended to, the brake lights go off autamatically.
This fault occured to me twice:-
1) In the first instance I got away by revving the car sensibally and applying/releasing the brakes using the brake padel -'pumping' (while stationary!). Fault disappeared!! Everything back to normal....
2) At the 2nd intant the fault symptoms came back after an oil change and some 30-40 miles of driving! At the time I was in my drive trying to reset my service interval display and the fault just popped up! So tried the revving bit..didn't work...had forgotten about the brake pumping bit!... checked forums on the internet and there was mention of brake switche etc... Bingo.....! It came back to me and I went out and pumped the brakes and sure enough the fault cleared.... the brake lights are off and I don't have to leave my battery disconnected to stop it from being drained!
I hope that's the last I see of it ..otherwise the brake switch near the pedal is a definate suspect in my book and will need replacing....!
I hope anyone out there benifits form my little contribution....
Thanks for reading!
Kool
June 2009