TM 5-3805-280-24-1
Diagnostic Information
Arm Reduced Leakage Valve
Boom Reduced Leakage Valve
Boom Regenerative Valve
Operational Function
To prevent arm in drift caused by
To prevent boom down drift caused
To route return oil from head end
leakage from the cylinder back
by leakage from the cylinders back
to rod end of boom cylinder to
through control valve.
through control valve.
Control Problems
Sticking or stuck check valve or pilot
Sticking or stuck check valve or pilot
Sticking or stuck check valve.
valve. No pilot pressure signal to
valve. No pilot pressure signal to
shift pilot spool.
shift pilot spool.
Machine Symptoms
Arm drifts down. Arm in speed is
Boom drifts down. Boom down
Boom lower speed becomes
slow or jerky if check valve sticking
speed is slow or jerky if check valve
slow with check valve stuck
or does not open.
sticking or does not open.
closed. Cannot raise tracks off
the ground using boom down
with check valve stuck open.
Laptop Computer with
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Excavator Diagnostic
Software Self-Diagnostic
Functions
Laptop Computer with
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Excavator Diagnostic
Software Monitoring
Function
Harness Check
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Notes
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Description of Operation
See Boom and Arm Reduced
See Boom and Arm Reduced
See Boom Regenerative Valve
Leakage Valve Operation in Group
Leakage Valve Operation in Group
Operation in Group 9025-05.
9025-05.
9025-05.
Bucket Flow Control Valve
Operational Function
To restrict oil flow to bucket circuit in combined operation of bucket,
9025
arm in, and boom up to ensure oil flows to higher-loaded boom
15
function to raise boom.
11
Control Problems
Pilot valves and poppet valve sticking or stuck.
Machine Symptoms
Bucket speed is slow if poppet valve is stuck closed. Boom is not
raised in combined operation with poppet valve stuck open or pilot
valves are stuck open keeping the poppet valve open.
Laptop Computer with Excavator Diagnostic Software Self-Diagnostic
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Functions
Laptop Computer with Excavator Diagnostic Software Monitoring
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Function
Harness Check
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Notes
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Description of Operation
See Bucket Flow Control Valve Operation in Group 9025-05.
TX,15,GG2238 1913AUG9810/10
6-100