Code 16 - Lift Down Valve - Short Circuit; Code 17 - Ground Control Module - In Fold Back; Code 18 - Alarm - Short Circuit - JLG 15MVL Series Service Maintenance Manual

Code 16 - Lift Down Valve - Short Circuit

Check For These Obvious Conditions First:
• Damaged wiring in the lift down valve wiring harness or a damaged lift down valve coil.
STEP
1. At the Ground Control Module, P1 connector, check the voltage across pins
10 and 3 to the lift down valve coil. Is reading within specification?
2. Remove the wire terminals at the lift down valve coil. Check resistance read-
ing of the coil. Is coil within specification?
3. With the terminals still removed from the lift down valve coil, check continu-
ity of the wires from pins 10 and 3 on the P1 connector to the lift down valve.

Code 17 - Ground Control Module - In Fold Back

Check For These Obvious Conditions First:
• Has machine been operating on a continuous grade or rough terrain for a long period of time.
STEP
1. Allow Ground Control Module to cool for 30 minutes. Does the machine
operate OK after cooling.
NOTE: If this is a recurring problem compare current draw of your machine with Ground Control Module specifications in
Table 6-3 - Amperage Draw for Various Components.

Code 18 - Alarm - Short Circuit

Check For These Obvious Conditions First:
• Damaged wiring in the alarm wiring harness or a damaged alarm.
STEP
1. At the Ground Control Module, P1 connector, check the voltage across
pins-13 and 6 to the alarm. Is reading within specification?
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.
3121231
Table 6-20. Code 16 - Lift Down Valve - Short Circuit
ACTION
Table 6-21. Code 17 - Ground Control Module - In Fold Back
ACTION
Table 6-22. Code 18 - Alarm - Short Circuit
ACTION
– JLG Lift –
SECTION 6 - TROUBLESHOOTING
SPEC YES
0 - 2V DC Go to Step 2
6 Ohms Go to Step 3
.00 Ohms —
SPEC YES
— —
SPEC YES
0 - 2V DC Go to Step 2
— Replace the Alarm
NO
Replace Ground
Control Module
Replace Coil
Repair or Replace
Wiring
NO
Replace Ground
Control Module
NO
Replace Ground
Control Module
Repair or
Replace Wiring
6-25