well knowing a little bit about the ray/cat trucks they are very similar to the raymonds, when they show a code 83 it is an E-Stop error.
Without knowing for sure what system is in your truck i'm just throwing this out here, it may or may not help.

Runtime FMEA has detected that the E Stop button was down.

System response-
-Alarm sounds: yes
-Operators Display:'Lift Emergency off button' turn key OFF
-PC contactor: denergised
-VM Display: 83
-Brake activated: no

Problem in the estop circuit

Possible causes:
estop switch defective
carriage board defective
mast cable bad
VM bad

this information may or may not help