Service Manual

SECTION 6 - TROUBLESHOOTING
6-24 – JLG Lift – 3121228
Code 18 - Alarm - Short Circuit
Check For These Obvious Conditions First:
• Damaged wiring in the alarm wiring harness or a damaged alarm.
Code 19 - Alarm - Disconnected
Check For These Obvious Conditions First:
• Damaged wiring in the alarm wiring harness or a damaged alarm.
• Activate a function to check if alarm beeps.
Code 20 - Beacon - Short Circuit
Check For These Obvious Conditions First:
• Damaged wiring in the beacon wiring harness or a damaged beacon unit.
Table 6-19. Code 18 - Alarm - Short Circuit
STEP ACTION SPEC YES NO
1. At the Ground Control Module, P1 connector, check the voltage across
pins-13 and 6 to the alarm. Is reading within specification?
0 - 2V DC Go to Step 2 Replace Ground
Control Module
2. Remove the wire terminals at the alarm, check continuity of each of the
wires from pins 13 and 6 on the P1 connector to the alarm end.
— Replace the Alarm Repair or
Replace Wiring
Table 6-20. Code 19 - Alarm - Disconnected
STEP ACTION SPEC YES NO
1. Check voltage at the P1 connector on the Ground Control Module between
pin-13 and pin-6. Is reading within specification?
2 - 4V DC Replace Ground
Control Module
Go to Step 2
2. Remove the wire terminals at the alarm, check continuity of each of the
wires from pins 13 and 6 on the P1 connector to the alarm end.
— Replace the Alarm Repair or
Replace Wiring
Table 6-21. Code 20 - Beacon - Short Circuit
STEP ACTION SPEC YES NO
1. At the Ground Control Module, P1 connector, check the voltage across
pins-12 and 5 to the beacon. Is reading within specification?
0 - 2V DC Go to Step 2 Replace Ground
Control Module
2. Remove the wire terminals at the beacon, check continuity of each of the
wir es f ro m p ins 12 an d 5 o n t he P1 c on nec to r t o t he beac on end .
— Replace the
Beacon
Repair or
Replace Wiring