Komatsu PC200-8M0, Shop Manual

Page: 1206 / 1254

100 Air conditioner
Failure code [879BKB] A/C Outer sensor Short Circuit
80-100
48
PC200, 200LC, 220, 220LC-8M0
SEN06151-00
Failure code [879BKB] A/C Outer sensor Short Circuit
Action
level
Failure code
Failure
Short circuit in air conditioner outside air temperature sensor
(Machine monitor system)
– 879BKB
Detail of failure q Air conditioner controller detected short circuit in outside air temperature sensor.
Action of con-
troller
q
The air conditioner controller sends information about the outside air temperature sensor short cir-
cuit to the machine monitor via CAN communication.
q
Continues control of air conditioner in automatic mode, ignoring data of outside air temperature
sensor.
Problem on
machine
q
Since there is a short circuit in the air conditioner outside air temperature sensor, outside temper-
ature is not counted in automatic mode.
(does not have any effect to the air conditioner in manual mode)
Related infor-
mation
q
Method of reproducing failure code: Turn starting switch to ON position.
q Check whether this failure code is displayed in the "Electrical Systems" (electrical systems abnor-
mality record) screen in the service mode of the machine monitor.
q For connectors etc., see "Parts and connectors layout".
q
Since connector ACECU of the air conditioner controller has small pins and does not have a
T-adapter, perform troubleshooting by using the intermediate connector (Although the intermediate
connector does not have a T-adapter either, it does have large pins).
q To replace the air conditioner harness between air conditioner controller connector ACECU and
intermediate controller, the air conditioner unit must be replaced.
Cause Procedure, measuring location, criteria and remarks
1
Defective outside air temperature
sensor
1. Turn starting switch to OFF position.
2. Disconnect connector P18.
Resistance Between P18 (male) (1) and (2) 25 °C
Approx.
1.7 k
z
2
Open or short circuit in wiring har-
ness
1. Turn starting switch to OFF position.
2. Disconnect connector AC01.
a
Same as above, if resistance is normal.
Resistance Between AC01 (female) (7) and (8) 25 °C
Approx.
1.7 k
z
3 Short circuit in wiring harness
a
If no failure is found by check for cause 2, this check is not required.
1. Turn starting switch to OFF position.
2. Disconnect connectors P18 and AC01.
Resistance
Between AC01 (female) (7) and (8), or between
P18 (female) (1) and (2)
Min. 1 M
z
4
Ground fault in wiring harness
(contact with ground circuit)
1. Turn starting switch to OFF position.
2. Disconnect connectors P18 and AC01.
Resistance
Between ground and AC01 (female) (8) or P18
(female) (1)
Min. 1 M
z
5 Defective air conditioner controller
If no failures are found by the above checks, the air conditioner controller may
be defective. (Since this is an internal defect, troubleshooting cannot be per-
formed.)
6 Defective air conditioner unit If no failure is found by above checks, air conditioner unit may be defective.