JLG 26MRT ANSI Service Manual User Manual
Page 48
SECTION 3 - TROUBLESHOOTING
3-4
– JLG Sizzor –
3120791
Table 3-2. Chassis Troubleshooting
TROUBLE
PROBABLE CAUSE
REMEDY
Drive System
No response to drive controller
Enable switch not activated. .
Activate enable switch
Controller not activated within three sec-
onds after enable switch is activated.
Activate enable switch, then activate drive
controller within three seconds.
Enable circuit not functioning properly.
Replace enable circuit card.
Hydraulic system oil low.
Replenish oil as necessary.
Hydraulic pump not functioning properly. Repair or replace pump.
Restricted or broken pump supply line.
Clean, repair or replace line.
Drive motor not functioning properly.
Repair or replace motor.
Damaged wiring on drive controller.
Repair or replace wiring.
Drive controller not functioning properly. Repair or replace controller.
Drive brake not releasing.
Determine cause and repair or replace
brake.
Machine drives erratically
Microcircuit on controller improperly
adjusted.
Adjust microswitch on controller for
proper operation.
Machine will not travel forward
Enable switch not activated.
Activate enable switch.
Drive controller not activated within three
seconds after enable switch is activated.
Activate enable switch, then activate drive
controller within three seconds.
Enable circuit not functioning properly.
Replace enable circuit card.
Hydraulic system oil low.
Replenish oil as necessary.
Restricted or broken hydraulic line or fit-
ting.
Clean, repair or replace line or fitting.
Control valve not functioning properly.
Repair or replace valve.
Drive motor not functioning properly.
Repair or replace motor.
Brake not functioning properly.
Repair or replace brake.
Engine will not respond when enable
switch is activated and drive controller is
activated .
Refer to Electrical System Troubleshoot-
ing - No response to control switch.
No electrical signal being sent to the drive
valve cartridge.
Refer to Electrical System Troubleshoot-
ing - No response to control switch.
Machine will not travel in reverse
See: Machine will not travel forward.