GolfSteve in Calgary
Clean it. Maybe there's some scale blocking the mechanism.

Otherwise take the door apart and replace the part. I did this on an old Bosch. Fairly easy job, about $50 for the part.

The difficult thing to diagnose is if the control panel is bad - you have to check if the controller is sending the electrical impulse to open the door at the right time. At the end of the day I just replaced the part and luck was on my side.