Would you mind sending us a picture or short video of the issue you are having? If the motors are connected to the controller box, you will get this issue. Often with older chairs rush can build up on those connectors and cause a break in continuity which can give this an error. Your user manual should tell you which motor is getting the disconnect.
If the motors are connected properly you should not be getting an error code unless a motor is bad.
The way the controller knows if the motors are engaged is by the lever on each motor. There is a circuit in each one. These are called brake switches.
If your wires are plugged in, and your motors are engaged (in the locked position) your chair should not be throwing fault codes. If the problem persists take the controller to a local dealer for service.