does this unit have a zapi controller? does the unit move, when pushed by hand, with the battery plugged in, (brakes release with battery power)?
There is a 2 wire molex connector, as part of the harness near the motor and controller, that allows the electrical brake to power up (release) when it is connected, so the unit can be pushed or moved even if the motor or controller is bad. if this connector is connected, I think these are the codes you get when you attempt to drive it normally.