Service Manual

SECTION 6 - TROUBLESHOOTING
3121228 – JLG Lift – 6-23
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.
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.
Table 6-17. Code 16 - Lift Down Valve - Short Circuit
STEP ACTION SPEC YES NO
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?
0 - 2V DC Go to Step 2 Replace Ground
Control Module
2. Remove the wire terminals at the lift down valve coil. Check resistance read-
ing of the coil. Is coil within specification?
6 Ohms Go to Step 3 Replace Coil
3. With the terminals still removed from the lift down valve coil, check continu-
it y of th e w ir es fro m p in s 1 0 a nd 3 o n t he P1 co nn ec to r to th e l if t do wn v al ve .
.00 Ohms — Repair or Replace
Wiring
Table 6-18. Code 17 - Ground Control Module - In Fold Back
STEP ACTION SPEC YES NO
1. Allow Ground Control Module to cool for 30 minutes. Does the machine
operate OK after cooling.
——Replace Ground
Control Module
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.