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Can you post the make and model number of the appliance please?
F43 means no tachometer signal from motor.
Check the wiring harness from the motor to the main power pcb.
Check the motor carbon brushes.
The worst case scenario; you may need a new motor or power module.
To open the door, unplug the appliance, wait 5 minutes then while it's unplugged try opening the door.
Hope this helps
Let me know how it goes or if you need more help