Service Manual Owner's manual
SECTION 3 - TROUBLESHOOTING
3-4 – JLG Lift – 3120728
Table 3-2. MC-1 ERROR CODES
(Indicated by rapid LED flashing and periodic beep)
ERROR
CODE
LED’S
FLASHING
PROBABLE CAUSE REMEDY
0 8 System Overvoltage - Charger Unplug Charger
0 8 System Overvoltage - Driving down long steep grade Operate ground controls to reduce voltage
1 7 Controller Overtemperature Turn unit off and allow to cool
28
Drive Motor Plug - Open Circuit - check connectors
X103 & X104
Properly attach wires or pins A1 & A2
28
Drive Motor Plug - Open Circuit - check motor con-
nections at motor
Properly attach wires or pins (WHT & BLK wires)
3 6 Brake Safety Relay Replace Controller
4 2 Brake Short Circuit Replace Brake
52
Brake Left Open Circuit - D-connectors to X103 &
X104 switched
Switch D-connectors - Left Motor to X103; Right
Motor to X104
52
Brake Left Open Circuit - Check pins 3 & 5 of X103
and brake wires
Properly attach wires or pins
52
Brake Left Open Circuit - Check brake wires or plug at
drive motor
Properly attach wires or pins
62
Brake Right Open Circuit - Check pins 2 & 5 of X104
and brake wires
Properly attach wires or pins
62
Brake Right Open Circuit - Check brake wires or plug
at drive motor
Properly attach wires or pins
7 2 Brake Open Circuit on one or both brakes See above
8 9 Switch Short Circuit (Joystick) Replace Joystick Box
9 6 Power Circuit Defect Replace Controller
10 1 Battery Low (< 16.5 v) Charge Battery
11 9
Check pins & wire connections at X102 & joystick
box connector
Properly attach wires or pins
11 9 Joystick defective Replace Joystick Box
12 8
Check pins & wire connections at X102 & joystick
box connector
Properly attach wires or pins
12 8 Joystick Box Replace Joystick Box
16 7
Current Limiting - Motor Short Circuit - Gearmotor
defective
Replace Gearmotor
21 6 36v supply Replace controller
24 5
Configuration Lost Reprogram using MC-1 software, if error reoccours
then replace controller
25 6 RAM ROM Replace controller