JLG 110HX ANSI Service Manual - Manual (Page 131)

SECTION 3 - TROUBLESHOOTING
3120636 – JLG Lift – 3-11
Machine will not travel in forward.
Hydraulic system oil low. Replenish oil as necessary.
Restricted or broken hydraulic line or fitting. Clean, repair or replace line or fitting.
Control valve not functioning properly. Repair or replace valve.
Drive motor(s) not functioning properly. Repair or replace motor(s).
Circuit breaker open. Determine and correct cause; reset circuit
breaker.
No power to wheel motor speed switch. See proper wiring diagram.
Two speed valve sticking. Repair or replace valve.
Counterbalance valve sticking on return side. Adjust return counterbalance out 3 turns - cycle
drive - return to original position.
Motor turns slowly in the direction of the last com-
mand.
Valve not returning to neutral. Check neutral springs.
Function speed switch malfunction. Replace function switch.
Sticking spool due to contamination. Remove end cap and check spool freedom.
Repair as necessary.
Motor turns slowly at maximum command.
Valve spool is not traveling far enough due to: Repair or replace drive motor(s).
Worn, leaking drive motor(s). Repair or replace drive motor(s).
Engine RPM’s set too low. Properly adjust engine RPM’s.
Low control pressure supply. Replace pressure regulator if necessary.
Function speed switch malfunction. Replace switch.
Amperage too low on controller. Correctly adjust controller.
Defective pump, low oil volume. Repair or replace pump.
Poor response, function shuts off slowly
when command is removed.
Low spool spring preload. Check for correct spring and shims in end caps.
Sticking spool due to contamination. Remove end cap and check spool freedom.
Ramp set too high in controller. Adjust controller.
Sticking control handle. Repair or replace controller.
Table 3-4. Chassis Assembly - Troubleshooting
TROUBLE PROBABLE CAUSE REMEDY