JLG 1250AJP Troubleshooting Manual page 107

Note Pretest Instructions
1.191.13
1.191.14 Disconnect main dump
solenoid [X074].
1.191.15 Disconnect main dump
solenoid [X074]. Ground
meter.
1.191.16 Disconnect main dump
solenoid [X074]. Start
machine. Fully stow boom,
center turntable between
rear wheels. ANALYZER ⇒
ACCESS LEVEL 1 ⇒ SER-
VICE MODE ⇒ MAIN LIFT.
Enter code 55050.
1.191.17 Ensure machine is in same
condition as step 1.191.16
Pretest Instructions. Fully
stow boom. Ground meter.
Take the following measure-
ment by backprobing. (See
Section 6. Multimeter
Basics on Pg. 319 for
details.)
1.191.18 Install a high pressure gauge
at the "MP1" port on the
main valve block. Remove
coil for the main tele propor-
tional valve [X072], but
leave harness connected.
1.191.19 Turn off machine. Discon-
nect PVG enable [X068].
Measure resistance of PVG
enable solenoid.
1.191.20 Swap cartridge from PVG
enable valve [[X068] with
the one in the main dump
valve [X074]
1.191.21 Turn off machine. Discon-
nect PVG enable [X068].
Ground meter. (See Section
6. Multimeter Basics on Pg.
319 for details.)
3128411
SECTION 1 - FAULT DICTIONARY AND SELECTED TROUBLESHOOTING
Test
Swap cartridge in main dump valve [X074]
with the one in the PVG enable valve[X068].
Does fault clear?
Measure resistance across the solenoid. Does
the solenoid measure approximately 7.2Ω?
Is there continuity between the black wire in
the connector for the main lift enable valve
solenoid [X082] and ground?
WHEN THE STABILITY CONTROL
IS OFF, THE MACHINE WILL TIP IF
USED INCORRECTLY.
Measure voltage across main dump solenoid
[X074] while operating boom lift. Only lift a
few feet or operate it several seconds. Does
the meter read about 12 VDC?
WHEN THE STABILITY CONTROL
IS OFF, THE MACHINE WILL TIP IF
USED INCORRECTLY.
Measure voltage at ground control module J2
pin 13 [X002.13.pin] while operating boom
lift. Only lift a few feet. Does the meter read
about 12VDC?
Start engine. While activating main tele,
observe pressure. Adjust pressure with the
adjustment screw under the high pressure
relief adjustment cover nut on the function
pump. Does the pressure read or adjust to
3400 psi?
Is resistance approximately 4.7 Ω?
Does fault clear?
Is there continuity between the black wire in
the connector of the PVG enable solenoid
[X068] and ground?
1250AJP
Result Corrective Action
Yes Replace cartridge originally in the main dump
valve [X074]
No Go to step 1.191.14
Yes Go to step 1.191.15
No Replace solenoid
Yes Go to step 1.191.16
No Repair/replace harness to ground including MTB
ground bus connector [X009]
Yes Go to step 1.191.18
No Keep machine in same condition. Go to step
1.191.17
Yes Turn off machine. Repair/replace harness
between ground control module J2 [X002] and
main dump solenoid [X074]
No Turn off machine. Replace ground control mod-
ule.
Yes Keep machine in same condition. Go to step
1.191.19.
No Repair/replace function pump or high pressure
relief circuit on the function pump
Yes Keep machine in same condition. Go to step
1.191.20.
No Replace PVG enable solenoid [X068]
Yes Replace PVG enable valve [X068] cartridge
No Go to step 1.191.21
Yes Go to step 1.191.22
No Repair/replace harness to ground including MTB
ground bus connector [X009]
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