dover t3 trouble

have a car that is intermittently trapping people once a day or so, service mode is door disconnect, as if you are turning off the door switch in the controller.
any ideas thanks

I have had a TAC 20 do that and it was a bad door board. Like it was loosing communication. Replaced the door board and no more problem. How do you get it running again?

I believe the mechanic just puts it on inspection to reset. have not been there yet, was just looking for a clue before i go. being lazy ha ha