Make sure the right motor brake is releasing. If you removed or replace the motor, make sure all cables were installed correctly. Check ohm reading from motor cable connections to frame, should not read. Make sure all cable connections from ESTOP, key switch, controllers and motors are clean and tight. When you have a code with an R or L, this usually means right or left motor or controller. Good Luck.

Updated with serial number.

Do you have a serial #