JLG 40H Service Manual - Manual (Page 130)

SECTION 3 - TROUBLESHOOTING
3-18
– JLG Lift – 3120240
High pump volume will not function. Boom above horizontal.
Horizontal limit switch out of adjustment.
Defective pump section.
Oil by-passing in step valve.
Electrical malfunction.
Lower boom.
Adjust limit switch to activate (close) with boom at
horizontal and below.
Repair or replace pump section.
Repair or replace step valve.
See proper wiring diagram.
High wheel motor speed will not function. Boom above horizontal.
Horizontal limit switch out of adjustment.
Two speed drive solenoid valve malfunctioning.
Drive pressure switch malfunctioning.
Valve orifice plugged.
Defective drive motor.
Grade too steep.
Lower boom.
Adjust limit switch to activate (close) with boom at
horizontal and below.
Repair or replace solenoid valve.
Replace pressure switch.
Unplug valve orifice.
Repair or replace motor.
Check tractability of machine.
TROUBLE PROBABLE CAUSE REMEDY