Machine Cannot Be Easily Steered Or Lacks Power - Komatsu ecot3 PC300LC-8 Shop Manual

40 Troubleshooting
H-20 Machine cannot be easily steered or lacks power
Trouble • Machine is not steered well or steering power is low.
Related infor-
• Set the working mode in P-mode before start.
mation
Malfunction of travel PPC
1
valve (steering spool)
Malfunction of travel junction
2
solenoid valve
Malfunction of travel junction
3
valve
Malfunction of merge-divider
4
solenoid valve
Possible causes
and standard
value in normal
Malfunction of merge-divider
state
5
valve
Malfunction of travel control
6
valve (spool)
Malfunction of travel control
7 valve (pressure compensa-
tion valve)
Malfunction of travel control
8
valve (suction valve)
Malfunction of LS shuttle
9
valve (bucket)
Defective seal of check valve
10
of LS pressure sensing part
Malfunction of travel motor
11
(safety valve)
Malfunction of travel motor
12
(check valve)
PC300, 350-8
Cause Standard value in normal state/Remarks on troubleshooting
a
a
Travel junction valve may have malfunction. Check it directly.
a
Merge-divider valve may have malfunction. Check it directly.
Spool of travel control valve may have malfunction. Check it directly.
Pressure compensation valve of travel control valve may have mal-
function. Check it directly.
Suction valve of travel control valve may have malfunction. Check it
directly.
LS shuttle valve of bucket control valve may have malfunction.
Check it directly.
Seal of check valve of LS pressure sensing part may be defective.
Check it directly.
Seal of safety valve of travel motor may have malfunction. Check it
directly.
a
Seal of check valve of travel motor may have malfunction. Check it
directly.
a
Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
Travel lever
Both sides in neutral
Either side operated
Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
Travel lever
Both sides operated
Either side operated
Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
Travel lever
Both sides in neutral
Either side operated
Motors of same type on forward and reverse sides or on right
and left sides may be checked by replacing them with each
other and seeing change of condition.
Motors of same type on forward and reverse sides or on right
and left sides may be checked by replacing them with each
other and seeing change of condition.
SEN02633-03
PPC valve output pressure
(steering)
2
0 MPa {0 kg/cm }
Min. 2.7 MPa
2
{Min. 28 kg/cm }
Solenoid output pressure
2
}
0 MPa {0 kg/cm
2.84 – 3.43 MPa
2
{29 – 35 kg/cm }
Solenoid output pressure
2
0 MPa {0 kg/cm }
2.84 – 3.43 MPa
2
{29 – 35 kg/cm }
1
23