POSSIBLE CAUSES
Faulty relief valve, auxiliary disable valve, proportional control valve or
control valve section; Cylinder failure; Pump is bad.
PROBLEM 27
Boom handling cylinders will not extend or retract.
CHECKS
Check for 12 volts at auxiliary disable valve when enabling cylinders.
No Volts12 Volts
Check for 3,500 psi at auxiliary system disable valve while enabling any
upper valve assembly control in retract direction. (See Tes t
25.)
3,500 psi or more
3,500 psi or less
Check diagnostic display screen (bank 3) for
change of 4 when enabling cylinders.
Check disable
valve wiring.
Consult dealer /
factory.
Change
No Change
3,500 psi or less
3,500 psi or more
3,500 psi or less
Check for 3,500 psi at auxiliary system disable valve while
enabling any other adapter frame valve section in retract
direction.
Adjust auxiliary system disable valve and check pressure.
(See Tes t
25.)
Replace auxiliary system disable valve.
Enable boom handling cylinder extend and retract solenoid valves
and check that voltage is present.
Voltage
No Voltage
Disconnect adapter frame valve assembly from proportional
flow control valve and plug valves. Check pressure at
auxiliary system disable valve.
3,500 psi or less
3,500 psi or more
Repair or replace proportional
flow control valve.
Repair or replace adapter
frame control valve.
Check for 12 volts at boom handling cylinder switch wire #55.
Voltage
No Voltage
Replace appropriate diode to wire #89D1.
Replace appropriate switch.
Replace counterbalance valve.
Repair or replace cylinder.
Yes
No
Exchange boom handling counterbalance
valve cartridges. Does problem cylinder
operate when enabled.
Repair or replace valve section.
3,500 psi or more
3,500 psi or less
Check for 3,500 psi at auxiliary system disable valve
while enabling boom handling cylinder control in
retract direction. (See Te s t
25.)
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