JLG 1250AJP Troubleshooting Manual page 163

tower lift down angles less than 3°. This fault is most likely caused by a mechanical or hydraulic failure, preventing the
machine from responding. Before troubleshooting, warm up the oil to operating temperature.
Note Pretest Instructions
1.361.1
1.361.2
1.361.3 Connect a 1000 psi pres-
sure gauge to MP1 on the
main valve manifold
1.361.4 Connect a 5000 psi pres-
sure gauge to MP1 on the
main valve manifold.
Remove the solenoid from
the main tele proportional
valve
1.361.5 Swap the main dump car-
tridge with the PVG enable
cartridge. Connect a 5000
psi pressure gauge to MP1
on the main valve manifold.
Remove the solenoid from
the main tele proportional
valve
1.361.6 Connect a 5000 psi pres-
sure gauge to LS on the main
valve manifold. ANALYZER
⇒ ACCESS LEVEL 1 ⇒
SERVICE MODE ⇒ SET
PRESSURES ⇒
CODE(146005) ⇒ TWR
LIFT? ⇒ ENTER
1.361.7 Connect a 5000 psi pres-
sure gauge to LS on the main
valve manifold. ANALYZER
⇒ ACCESS LEVEL 1 ⇒
SERVICE MODE ⇒ SET
PRESSURES ⇒
CODE(146005) ⇒ TWR
TELE? ⇒ ENTER
1.361.8 Swap the tower lift enable
valve cartridge with the main
lift enable valve cartridge
1.361.9 Swap the tower tele enable
valve cartridge with the main
lift enable valve cartridge
3128411
SECTION 1 - FAULT DICTIONARY AND SELECTED TROUBLESHOOTING
Test
Examine the electrical connections at the
tower cylinder angle sensor [X092] and BLAM
module J3 connector [X088]. Is there any
loose connections or moisture or corrosion?
Is the tower angle sensor properly mounted to
the machine?
With the machine idling, does the gauge read
about 300 psi?
While activating main telescope in, does the
gauge read 3400 psi?
While activating main telescope in, does the
gauge read 3400 psi?
While activating tower lift UP , does the gauge
read 2755 to 3088 psi AND while activating
tower lift DOWN, does the gauge read 2755 to
3088?
While activating tower tele Out, does the gauge
read 2537 to 2871 psi AND while activating
tower tele IN, does the gauge read 2537 to
2871?
Will the tower now lift and is the fault cleared? Yes
Will the tower now lift and tele and is the fault
cleared?
1250AJP
Result Corrective Action
Yes Clean or replace any bad connections
No Go to step 1.361.2
Yes Go to step 1.361.3
No Remount the sensor
Yes Go to step 1.361.4
No Adjust the outside relief on the function pump till
gauge reads 300 psi. If adjustment does not cor-
rect the pressure, replace the control valve on the
function pump
Yes Go to step 1.361.6
No Adjust the inside relief on the function pump till
the gauge reads 3400 psi while activating the
function. If adjustment does not correct the pres-
sure, go to step 1.361.5
Yes Replace the cartridge originally from the main
dump valve
No Replace the control valve on the function pump
Yes Go to step 1.361.7
No Replace the tower lift PVG Section
Yes Go to step 1.361.8
No Replace the tower tele PVG Section
Replace the valve cartridge originally from the
tower lift enable
No Go to step 1.361.9
Yes Replace the valve cartridge originally from the
tower tele enable
No Go to step 1.361.10
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