Machine Is Not Steered Well Or Steering Power Is Low; Travel Speed Does Not Change - Komatsu PC130-7 Shop Manual

TROUBLESHOOTING
H-19 Machine is not steered well or steering power is low
Trouble

• Machine is not steered well or steering power is low.

Related
• Carry out the troubleshooting in working mode A.
information
Malfunction of travel PPC
1
valve
Possible causes
and standard Malfunction of travel junc-
2
tion valve
value in normal
state
Malfunction of travel control
3
valve (spool)
Malfunction of travel control
4 valve (pressure compensa-
tion valve)
Malfunction of travel control
5
valve (suction valve)
Malfunction of travel motor
6
(safety-suction valve)
H-20 Travel speed does not change
Trouble

• Travel speed does not change.

Related
• Carry out the troubleshooting in working mode A.
information
Possible causes
Malfunction of travel speed
and standard 1
shifting solenoid valve
value in normal
state
Malfunction of travel motor
2
(speed shifting section)
PC130-7
Cause Standard value in normal state/Remarks on troubleshooting
aPrepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
FORWARD or REVERSE position
The travel junction valve of the control valve may have a malfunction.
Check it directly.
The spool of the travel control valve may have a malfunction. Check it
directly.
The pressure compensation valve of the travel control valve may have a
malfunction. Check it directly.
The suction valve of the travel control valve may have a malfunction.
Check it directly.
The safety-suction valve of the travel motor may have a malfunction.
Check it directly.
Cause Standard value in normal state/Remarks on troubleshooting
aPrepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Travel speed switch
Lo position
Hi position
The speed shifting section of the travel motor may have a malfunction.
Check it directly.
Travel lever
Neutral position
Travel lever
Neutral position
FORWARD or
REVERSE position
H-19, H-20
PPC valve output pressure
0 MPa
2
{0 kg/cm }
2.84 – 3.43 MPa
2
{29 – 35 kg/cm }
Solenoid valve output
pressure
0 MPa
2
{0 kg/cm }
2.84 – 3.43 MPa
2
{29 – 35 kg/cm
20-519
}
(1)