Main Lift Pvg Valve Obstructed - JLG 1250AJP Troubleshooting Manual

Note Pretest Instructions
1.213.5 Take the following measure-
ment by backprobing. See
Backprobing on Pg. 319 for
details. Turn on machine
after setting up measure-
ment.
1.213.6 Take the following measure-
ment by backprobing. Turn
on machine after setting up
measurement.

1.214 MAIN LIFT PVG VALVE OBSTRUCTED

Flash Code: 4-5
Main lift PVG valve obstructed. Main lift PVG valve spool is not free to move completely. This could be from contamination
inside the valve or a blocked filter.
Note Pretest Instructions
1.214.1
1.214.2
1.214.3
1.214.4 Mark to identify the main lift
PVG valve actuator [X065]
using string, tape, etc. Swap
it with an actuator that
doesn't have a fault.
1.214.5
1.214.6 Inspect all 4 hydraulic filters
and housings and replace all
4 filters: output of function
pump, platform filter (If filter
is not external to platform
valve it must be updated.),
return filter and charge filter
(for drive pump). Take note
of filters/housings that have
contamination.
1.214.7
3128411
SECTION 1 - FAULT DICTIONARY AND SELECTED TROUBLESHOOTING
Test
Is there about 12VDC between ground module
J2 terminal 11 [X002.11] and any terminal on
the MTB ground bus -12 pos. [X009]?
Is there about 12VDC between ground module
J2 terminal 11 [X002.11] and ground module
J8 terminal 1?
Test
Is there dirt in the hydraulic module part of the
valve, especially around the spool?
Is the filter at the main lift PVG valve [X065]
pilot oil inlet blocked?
Is the fault clear?
Perform 5.4 Calibrating Boom Valves on Pg.
296. Does fault move to new location of actua-
tor?
Does the return filter have contamination in fil-
ter media or housing?
Cycle boom from fully lowered and retracted
to fully extended and then back. Test hydraulic
fluid. Does it test bad, appear cloudy, appear
dark, smell burned or is otherwise abnormal?
-OR- Was there any contamination in the filters
or housings?
Do machine hydraulics function properly?
1250AJP
Result Corrective Action
Yes Repair/replace harness from main lift PVG valve
[X065] to ground J2 [X002] and the MTB ground
bus -12 pos. [X009].
No Go to step 1.213.6
Yes Repair harness between ground module J2
[X002] and MTB ground bus -12 pos. [X009]
No Reprogram/replace ground module
Result Corrective Action
Yes Clean and repair as needed.
Go to step 1.214.2
No Go to step 1.214.2
Yes Clean and repair as needed.
Go to step 1.214.3.
No Go to step 1.214.3
Yes Go to step 1.214.5
No Go to step 1.214.4
Yes Replace PVG valve actuator that was initially on
the main lift PVG valve [X065].
Go to step 1.214.5
No Replace hydraulic module of main lift PVG valve
[X065].
Go to step 1.214.5
Yes Go to step 1.214.6
No Troubleshooting complete
Yes Replace all hydraulic fluid
Go to step 1.214.7
No Go to step 1.214.7
Yes Troubleshooting complete
No Replace hydraulic components that are not func-
tioning properly. Focus first on components
upstream of any filters/housings with contamina-
tion. Calibrate if necessary.
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