Renently my A3 1997 8l speedometer unit clock is not showing real car speed by less than 20 to 30 km/h less. The pointer or arrow showing speed stands below 0 km/k even when the car is at the minimum speed, while compared to other cars the speedometer arrow stands always at 0 km/h and not less than that only when car is off. I made the inpection and mechanics told me to change whole control panel cluster.
any idea what might be going wrong with that.