Error Code [251] (Abnormality In Overload Pressure Sensor) - Komatsu PC130-7 Shop Manual

TROUBLESHOOTING

Error code [251] (Abnormality in overload pressure sensor)

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