That is not the proper way to diagnose or fix a modern car.A simple scan with DIS or ISTA will tell you the problem with a very high probability to be fixed at first attempt.
Here is how the valvetronic works:the TB is closed at start-up and opens completely a few seconds after the engine is running.The function of the TB (regulating engine RPM and output) is performed by the Valvetronic:min valve lift=idle,max valve lift=max power,and everything in between.If there is a malfunction in the Valvetronic system registered by the ECU,valve lift is set to max and the Valvetronic is disabled.At this point the engine is controlled exactly as a conventional engine-with the TB.