A few months ago, the instrument cluster on my Audi TT started behaving very oddly for the first twenty seconds after I started the car in the morning. As time passed, twenty seconds became thirty, forty, … and then up to two minutes before returning to normal behavior. The colder the weather, the longer it lasted.
So, exactly what do I mean by oddly? Well, the needles on the temperature and fuel gauges would slam back and forth wildly. The tach and speedometer gauges would jump from zero to very high RPMs or speeds, respectively, then fall back to zero. Diagnostic lights would come on and go off, with their accompanying beeps. See for yourself.
It got so bad that finally the instrument cluster stopped talking to the immobilizer. This caused the immobilizer to think the car was being stolen, so it kept killing the engine when I tried to start it.
At that point, I had to have the instrument cluster replaced. Although this is a common problem with TTs, Audi has yet to issue a recall in the US.
And, no, the mice had nothing to do with this.