Thanks for any answers. I will check.

Make sure your battery isn't dead/bad/out of water or that you're losing voltage somewhere when you put a load on the machine.

I've seen machines throw these codes when the voltage drops low when the contacts pull in. The increased load drops the battery volts, the contacts lose their holding current and drop out. Power comes back when the battery recovers cause the load is removed. It's like turning the key off and back on real quick.

Check your battery. Always check your power supply first.

check foward reverse lever/monotrol, brake switch, start switch, key switch, and all associated wiring if all these check good then problem is most likely in the control card