Komatsu Galeo PC138US-8 Shop Manual page 698

40 Troubleshooting
Trouble (8) Air conditioner abnormality record: External air sensor "Unused"
• External air sensor is not used in air conditioner system of this machine.
Related
• If "CAN disconnection" is displayed as communication condition, communication cannot be carried
information
out normally. Accordingly, this condition is not displayed.
Possible causes
and standard
value in normal
1 Normal display
state
Trouble (9) Air conditioner abnormality record: Air flow sensor "Abnormality"
• If "CAN disconnection" is displayed as communication condition, communication cannot be carried
Related out normally. Accordingly, this condition is not displayed.
information • Method of reproducing abnormality record: Turn starting switch ON + Turn air conditioner (A/C)
switch ON.
Defective air flow sensor
1 (Internal disconnection or
short circuit)
Disconnection in wiring har-
ness (Disconnection in wiring
2
or defective contact in con-
nector)
Possible causes
and standard
value in normal
state
Ground fault in wiring har-
3 ness (Short circuit with GND
circuit)
Hot short (Short circuit with
4
24V circuit) in wiring harness
Defective air conditioner con-
5
troller
PC138US, USLC-8
Cause Standard value in normal state/Remarks on troubleshooting
Since external air sensor is not used in air conditioner system of
this machine, above display is normal.
Cause Standard value in normal state/Remarks on troubleshooting
a Prepare with starting switch OFF, then carry out troubleshoot-
a Prepare with starting switch OFF, then carry out troubleshoot-
Wiring harness between AC
(12) – TH
Wiring harness between AC
(27) – TH
a Prepare with starting switch OFF, then carry out troubleshoot-
Wiring harness between AC
(12) – TH
a Prepare with starting switch OFF, then turn starting switch ON
Wiring harness between AC
(12) – TH
If causes 1 – 4 are not detected, air conditioner controller may be
defective. (Since trouble is in system, troubleshooting cannot be
carried out.)
ing without turning starting switch ON.
TH (device side)
F
Between (1) – (2)
ing without turning starting switch ON.
W
(wiring side) (2)
F
W
(wiring side) (1)
F
ing without turning starting switch ON.
W
(wiring side) (2)
F
and carry out troubleshooting.
W
(wiring side) (2)
F
SEN02467-00
Resistance
100 z – 115 kz
(wiring side) Resis-
tance
(wiring side) Resis-
tance
(wiring side) Resis-
tance
(wiring side)
Voltage Max. 1 V
Max. 1 z
Max. 1 z
Min. 1 Mz
45