when the car is started all the lights on the dash should go out.....instead the brake,oil level and abs lights keep flashing as though the cars ignition is on only.......also the rev counter stops working then when it feels like rev counter kicks back in and all go's back to normal..............any idea'S ? Vcds shows no faults at all.......car is a 1996 'N' plate audi a4 1.8 petrol