Komatsu PC130-7, Shop Manual

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20-404
PC130-7
TROUBLESHOOTING
(1)
E-1 Engine does not start
Trouble • Engine does not start
Related
information
• The engine starting circuit is equipped with the start lock function of safety lock lever type.
Possible causes
and standard
value in normal
state
Cause Standard value in normal state/Remarks on troubleshooting
1 Low charge level of battery
Battery voltage Electrolyte specific gravity
Min. 24 V Min. 1.26
2 Defective fuse No. 3 or 18
If the fuse is broken, the circuit probably has a grounding fault, etc.
(See Cause 10.)
If the fuse is not broken and the monitor panel does not light up, check
the power supply circuit between the battery and fuse box, too.
3
Defective starting switch
(Internal disconnection)
a
Prepare with starting switch OFF, then carry out troubleshooting with-
out turning starting switch.
H15 (male) Starting switch Resistance
Between (1) and (4)
OFF Min. 1 M
z
START Max. 1
z
4
Defective safety lock switch
(Internal disconnection)
a
Prepare with starting switch OFF, then carry out troubleshooting with-
out turning starting switch.
S14 (female) Safety lock lever Resistance
Between (1) and (3)
Free Min. 1 M
z
Lock Max. 1
z
5
Defective starting motor
cutout relay R11 or R13
(Internal disconnection or
short circuit)
a
Prepare with starting switch OFF, then carry out troubleshooting with-
out turning starting switch.
R11 (female), R12 Resistance
Between (1) and (2) 100 – 500
z
Between (3) and (5) Min. 1 M
z
Between (3) and (6) Max. 1
z
6
Defective starting motor
safety relay
(Internal defect)
a
Prepare with starting switch OFF (Disconnect only terminal C), then
turn starting switch to START position and carry out troubleshooting.
Relay terminal, A27
Starting
switch
Voltage/Resistance
Between B and
chassis ground Power
supply
START
20 – 30 V
Between E and
chassis ground
GND Max. 1
z
Between A27 (2) and
chassis ground
Genera-
tion signal
Max. 1 V
Between A27 (1) and
chassis ground
Starting
input
20 – 30 V
Between C and
chassis ground
Starting
output
20 – 30 V
If the power supply, GND, generation signal, and starting input are nor-
mal and the starting output is not normal, the starting motor safety relay
is defective.
7
Defective starting motor
(Internal defect)
a
Prepare with starting switch OFF, then turn starting switch to START
position and carry out troubleshooting.
Starting motor
Starting
switch
Voltage
Between B and
chassis ground Power
supply
START
20 – 30 V
Between C and
chassis ground
Starting
output
20 – 30 V
If the power supply and starting signal are normal and the starting motor
does not rotate, the starting motor is defective.
E-1