Auto-Decelerator Does Not Work; Fine Control Mode Does Not Function Or Responds Slow - Komatsu ecot3 PC300LC-8 Shop Manual

SEN02633-03
H-5 Auto-decelerator does not work
Trouble • Auto-decelerator does not operate.
• Carry out this troubleshooting if auto-decelerator does not operate when travel lever is operated.
Related infor- (Shuttle valve (in PPC valve) is installed between PPC valve and oil pressure switch of only in travel
mation circuit.)
• Set the working mode in P-mode before start.
Possible causes
and standard
Malfunction of travel PPC
value in normal
1
valve (shuttle valve)
state
H-6 Fine control mode does not function or responds slow
Trouble • Fine control performance or response is low.
Related infor-
• Set the working mode in P-mode before start.
mation
1 Malfunction of LS-EPC valve
2 Clogging of LS circuit orifice Orifice of LS circuit may be clogged. Check it directly.
Possible causes
and standard
value in normal
state
Defective adjustment or mal-
3
function of LS valve
4 Malfunction of servo piston
12
Cause Standard value in normal state/Remarks on troubleshooting
a
Cause Standard value in normal state/Remarks on troubleshooting
a
a
Measured oil pres-
Pump discharge
pressure
LS valve output pres-
sure
If oil pressure does not become normal after adjustment, LS valve
may have malfunction or internal defect. Check LS valve directly.
Servo piston may have malfunction. Check it directly.
Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
Travel lever
Neutral
Operated
Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
Travel speed Travel lever
Lo
Hi Lifting operation
Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
sure
All levers in neutral
Almost same pres-
40 Troubleshooting
PPC valve output pressure
0 MPa {0 kg/cm
Min. 2.7 MPa
{Min. 28 kg/cm
LS-EPC output
pressure
Approx. 1.4 MPa
Neutral
{Approx. 14 kg/cm
0 MPa {0 kg/cm
Oil pressure ratio
Travel with no load
(Lever operated
halfway)
sure
Approx. 3/5
PC300, 350-8
1
2
}
2
}
1
2
}
2
}
1