5-45
5
TROUBLESHOOTING
AUXILIARY HYDRAULICS
Proportional control is not possible
1
Check the operation of
actuators other than of
the auxiliary piping
Normal
2
Check
the proportional
controller
Faulty
Repair
or replace the propor-
tional contr
oller
Normal
3
Check
the proportional
control solenoid valve
Faulty
Repair
or replace the propor-
tional contr
ol solenoid valve
1. Check the operation of actuators other than of the
auxiliary piping
Determine if only the auxiliary piping is faulty by check-
ing
the operation of actuators for the devices listed in
the table on the right. If one of them is faulty, check the
main relief valve and the hydraulic pump (P3).
“5-8”
2. Check the proportional controller
“4. Disassembly and assembly, Proportional con-
trol”
3. Check the proportional control solenoid valve
a. Disconnect the hose connecting the solenoid valve
and the control valve (auxiliary section) from the
control valve.
b. Fit the pressure gauge to the hose just disconnect-
ed.
c.
Operate the proportional control lever on the left pi-
lot
valve. If the pressure is between 0 and 3.4 MPa
depending on the lever angle, the proportional con-
tr
ol solenoid valve is normal.
Lever to operate Device to check
Bucket Relief valve R3 Pump P3
AUXILIARY HYDRAULICS
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