I'm getting code 21 with the new style PTU as soon as I turn the ignition on without starting the engine. If i try to reset it will come right back. The odd thing is the car starts and runs perfectly without any hesitation or things like that. I have tried to clean PTU-harness, ground connections, swapped to another PTU with no luck. Is there anything else that may throw 21? Ignition coils?
The car is a 1990 TT euro-model. Thanks in advance.