TAC 50-04 Velocity Tracking Fault 693

I have encountered this fault often on one of my units. I find the car floor level each time. I've rerouted the encoder wires outside of the controller to reduce RF interference. I've changed the encoder interface at the drive and the motor to no avail. The coupling to the motor shaft is tight. I was informed from a TKE engineer that door locks are a common denominator with this fault. I've gone through every lock and the gate to ensure they are .02ohms or less when closed. I didn't suspect this would solve the issue but I'm open to any suggestions. I came in this morning to find it was shut down with the same fault. Have any of you folks stumbled with this issue?

If you do an FLTN, when is the fault happening? How fast is it going, up or down, etc. What kind of drive and what kind of machine?

Check that there are MOV on the relay coils especially in the brake circuit