Gem code 66

I just got a gem car and it shows code 66 when i turn it on ,over current on the field wire? so without the field wire on it still has the same code. is the controller bad?

I would suggest checking the field wires to see if either chaffed through on the frame somewhere and grounded out. I have in the past noticed arcing on the motor itself where the cable lugs attach. Turns out, the the steel lugs had rusted. This accumulated rust created a current path and error code. Next, I would remove both field wires from the motor and check for grounding of the field winding. Then check the resistance of the field winding. The factory may be able to give you the values, or compare with a good GEM. If there is any reading to ground, or if the winding resistance is low, check to see if trans axle oil has entered the motor. This happens if the o ring or the sealed ball bearing fails. The o ring and bearing are available after market. If all else fails, the factory can test your controller. I believe Ride for Fun will also do this.


I have a code of -04. I just put new trojan batteries in it and it won’t run. Can anyone help?

-04 indicates normal operation and is not an error code.

Ok so it won’t run…What do you think it is? Also I have a few wires that are hanging loose I would like to send to you. Can I email them to you? I am in desperate need of help because those batteries weren’t cheap and the car won’t run. Thanks in advance!


Did the GEM run before the batteries were replaced? What year do you have? Do you here the main relay close after selecting forward or reverse?