Curtis Controller 1286 fault on Tomberlin

I need some help folks. I am getting a five five fault on the Curtis 1286 controller on my Tomberlin cart. Not sure I understand what it means or what to look for.

Fault code five five; Main Contactor Open.

The cart jerks but won't move very far. Not sure if it's the speed sensor, a solenoid or controller issue.

Any help is greatly appreciated!