The EuroVan uses an electronically controlled transmission which sets the shift points based on engine load and rpm information that is tuned to your specific driving habits. Sometimes this information gets garbled or for whatever reason may need to be reset to the default patterns so that it can begin to re-learn from your driving habits. The correct sequence is:
Turn on ignition without starting engine.
Turn off ignition.
Turn on ignition again without starting engine and depress the accelerator pedal all the way to the floor and hold it there for at least ten seconds.
Release the accelerator pedal and turn the key to start the engine in the regular manner.
Drive away going through all four gears.