JLG 400CRT ANSI Service Manual - Manual (Page 44)

SECTION 3 - TROUBLESHOOTING
3-2 – JLG Lift – 3121111
.
Table 3-1. Elevation System Troubleshooting
TROUBLE PROBABLE CAUSE REMEDY
Platform Elevation System
No Response to LIft Control
Lift not performed within three seconds after lift
function switch is selected. Reselect lift function switch, then activate joystick
within three seconds.
Lift control switch inoperative. Repair or replace control switch.
Hydraulic system oil low. Replenish oil as necessary.
Restricted or broken supply line on valve
bank or pump. Clean, repair or replace line.
Control valve not functioning properly. Repair or replace valve.
Lift cylinder not functioning properly. Repair or replace cylinder.
Hydraulic pump not functioning properly. Repair or replace pump.
Platform will not raise.
Joystick not activated within three sec-
onds after lift switch is activated. Activate lift switch, then activate joystick
within three seconds.
Load capacity exceeded. (Personnel
and/or equipment on platform). Reduce load. (Refer to capacity placard).
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.
Lift cylinder not functioning properly. Repair or replace lift cylinder.
Engine does not respond when lift control
switch is moved to up position. Refer to Electrical System Troubleshoot-
ing - No response to control switch.
No electrical signal being sent to lift up control valve
cartridge. Refer to Electrical System Troubleshooting - No
response to control switch.
Platform will not lower
Joystick not activated within three sec.
after lift switch is activated. Depress lift switch, then activate control-
ler within three seconds.
No electrical signal sent to lift down con-
trol valve cartridge. Refer to Electrical System Troubleshoot-
ing - No response to control switch.
Lift down control valve cartridge not functioning
properly. Repair or replace lift down control valve
cartridge.
Lift cylinder not functioning properly. Repair or replace lift cylinder.
Engine does not respond when lift switch
is moved to down position. Refer to Electrical System Troubleshoot
ing - No response to control switch.
No electrical signal being sent to lift down
control valve. Refer to Electrical System Troubleshoot
ing - No response to control switch.
Platform raises and lowers erratically
Hydraulic system oil low. Replenish oil as necessary.
Restricted or broken hydraulic line or fit-
ting. Clean, repair or replace line.