MCE direction loss

We have a traction 2001 vintage MCE intermittently shutting down in mid flight with a direction loss fault. The power supply checks good it was replaced about a year ago we have checked our safety string devices for good connections also went through all the hoistway doors and locks. Any one have any ideas on what could cause this?

Had a similar problem once, it turned out to be worn shoes on the selector tape. Maybe worth a look.

Ended up being a bad position encoder inside the selector. We replaced the selector guide shoes and then the car wouldn’t run on auto. That’s what clued us in on the selector.