If the reading is below 22 volts, recharge or replace the batteries.
Check to see if the code changes to the opposite side (ie, left to right). If the code changes, the problem is in a motor. If the code stays the same , the controller is bad.
At this point , both motors should be checked for open or shorted armatures. This is because sometimes the controller can`t tell its “right from its left”.
To test a motor, remove the motor plug from the controller. With your ohmmeter set on the 200 ohm scale insert the test leads into the bottom two terminals on the motor plug.
You should read between .8 and 4 ohms. If it is less there is a short in the armature. If it is high, or no reading at all, there is an open circuit. Check the motor brushes to see if they are worn or burned. If they appear to be good, then the motor/gearbox has to be replaced.
You should get a reading between 50 and 90 ohms. If there is no reading at all, the brake winding is open, or the microswitch on the body of the brake is broken. If it is too low, there is a short in the winding. In either case, it is non-