Komatsu Galeo PC800-8, Shop Manual

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30
PC800, 850-8
SEN00793-02 40 Troubleshooting
E-13 Hydraulic oil temperature gauge does not display correctly
Circuit diagram related to hydraulic oil temperature sensor
Failure
phenomenon • Hydraulic oil temperature gauge does not dis-
play correctly
(1) Hydraulic oil temperature rises normally, but the dis-
play does not exceed the white range (C).
(2) Hydraulic oil temperature remains stable, but the
display rises up the red range (H).
Relative
information • Input from the hydraulic oil temperature sensor can be confirmed in the monitor function.
(Code No. 04401 : Hydraulic oil temperature, 04402 : Hydraulic oil temperature sensor voltage)
Possible causes
and standard
value in normal
state
Cause Standard value in normalcy and references for troubleshooting
1
Hydraulic oil temperature
sensor fault
(Internal disconnection,
short-circuiting or ground-
ing fault)
a
Turn the engine starting switch OFF for the preparations, and hold it in
the OFF position during the troubleshooting.
P22 (male)
Hydraulic oil tempera-
ture
Resistance
Between (1) – (2)
10 – 100°C
90 – 3.5 k
z
Between
(1) – chassis ground
Min. 1 M
z
2
Disconnection of wiring
harness
(Disconnection or defec-
tive contact with connector)
a
Turn the engine starting switch OFF for the preparations, and hold it in
the OFF position during the troubleshooting.
Wiring harness between CM02 (female) (12) –
P22 (female) (1) Resis-
tance
Max. 1
z
Wiring harness between CM02 (female) (13) –
P22 (female) (2) Resis-
tance
Max. 1
z
3
Grounding fault of wiring
harness
(Contact with grounding
(GND) circuit)
a
Turn the engine starting switch OFF for the preparations, and hold it in
the OFF position during the troubleshooting.
Wiring harness between CM02 (female) (12) –
P22 (female) (1) and chassis ground Resis-
tance
Min. 1 M
z
4
Short-circuiting of wiring
harness
(Contact with 24 V circuit)
a
Turn the engine starting switch OFF for the preparations, and hold it in
the ON position during the troubleshooting.
Wiring harness between CM02 (female) (12) –
P22 (female) (1) and chassis ground
Voltage Max. 1 V
5 Defective machine monitor
a
Turn the engine starting switch OFF for the preparations, and hold it in
the OFF position during the troubleshooting.
CM02 (female)
Hydraulic oil tempera-
ture
Resistance
Between (12) – (13)
10 – 100°C
90 – 3.5 k
z
Between
(12) – chassis ground
Min. 1 M
z