Komatsu PC130-7, Руководство по ремонту

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20-350
PC130-7
TROUBLESHOOTING
Error code [251] (Abnormality in overload pressure sensor)
User code Error code
Trouble
Abnormality in overload pressure sensor
(Governor and pump controller system)
– 251
Contents of
trouble
• The signal voltage from the overload pressure sensor is below 0.3 V or above 4.72 V.
Action of
controller
• Sets the boom cylinder bottom pressure to 0 MPa {0 kg/cm
2
} for control.
• If the cause of the failure disappears, the system resets itself.
Problem that
appears on
machine
• The overload caution function does not operate (The load pressure on the boom cylinder bottom side
cannot be sensed).
Related
information
a
If the 5-V circuit (B) and ground circuit (A) of the pressure sensor are connected inversely, the pressure
sensor will be broken. Accordingly, take extreme care when checking.
Possible causes
and standard
value in normal
state
Cause Standard value in normal state/Remarks on troubleshooting
1
Defective sensor power
supply system
If error code [226] is displayed, carry out troubleshooting for it first.
2
Defective overload pres-
sure sensor (Internal
defect)
a
Prepare with starting switch OFF, then hold starting switch ON or start
engine and carry out troubleshooting.
A70 Voltage
Between (B) and (A) Power supply 4.5 – 5.5V
Between (C) and (A) Signal 0.5 – 4.5V
The pressure sensor voltage is measured with the wiring harness con-
nected. Accordingly, if the voltage is abnormal, check the wiring har-
ness and controller, too, for another cause of the trouble, and then
judge.
3
Disconnection in wiring
harness (Disconnection in
wiring harness or defective
contact in connector)
a
Prepare with starting switch OFF, then carry out troubleshooting with-
out turning starting switch.
Wiring harness between C01 (female) (22) and
J07 and A70 (female) (B)
Resistance
Max. 1
z
Wiring harness between C01 (female) (10) and
A70 (female) (A)
Resistance
Max. 1
z
Wiring harness between C01 (female) (7) and
A70 (female) (C)
Resistance Max. 1
z
4
Short circuit with chassis
ground in wiring harness
(Contact with ground cir-
cuit)
a
Prepare with starting switch OFF, then turn starting switch ON and car-
ry out troubleshooting.
Between C01 (female) (7) - A70 (female) (C)
wiring harness and chassis ground
Resistance
Min. 1 M
z
5
Short circuit with power
source in wiring harness
(Contact with 24-V circuit)
a
Prepare with starting switch OFF, then turn starting switch ON and car-
ry out troubleshooting.
Between C01 (female) (22) – J07 – A70
(female) (B) wiring harness and chassis ground
Voltage Max. 1 V
Between C01 (female) (7) – A70 (female) (C)
wiring harness and chassis ground
Voltage Max. 1 V
6
Defective governor and
pump controller
a
Prepare with starting switch OFF, then turn starting switch ON and car-
ry out troubleshooting.
C01 Voltage
Between (22) and (10) Power supply 4.5 – 5.5 V
Between (7) and (10) Signal 0.5 – 4.5 V
[251]
(1)