Computer board problem.

Update:
Could it be also a weak battery (45ah) causing this problem?
I didnt know my car came with this battery until recently, is that every car dealers in UK have the bad habbit of selling a car with a weak battery? It is the second car I buy in UK with a weak battery from a car dealer!

Update:
I have found a new issue, isn't the clock and miles counter supposed to stay visible when I turn off the engine and take the keys off? I have seen that in other Passat's, so that tells me it is the problem, when I turn off the engine the clock and miles counter go blank, anyone has any idea of what that could be? Please help! It would save me a few quids.

Mr.Mhan said:

When I turn off the engine, the clock and miles counter go blank.

Click to expand...

That shouldn't happen. Look around under the dash to see if someone has done some "creative" re-wiring. Is there an after market radio installed? An after market alarm or remote-starter? If a circuit that should be connected to constant power has been rewired to switched power, you'd get that sort of problem. A wiring diagram would help you trace down which wires to look for. Probably one of the power feeds to the instrument cluster. The cluster uses the car battery power for this memory function.

It could also be a bad cluster.

I'm not sure if a failed ignition switch could cause this or not.