Troubleshooting For Power Supply System (Air Conditioner Does Not Operate) - Komatsu PC88MR-10 Shop Manual

A-1 Troubleshooting for power supply system (Air conditioner does not
operate)
(PC88MR-FJ0-400-A-Z0-A)
Air conditioner does not operate due to power supply system failure.
Failure
[DAZQKR] is displayed on the operation screen of machine monitor.
Problem on
No air blows out (Blower motor does not rotate).
machine
If failure code [DAZQKR] is displayed on the machine monitor, perform this
troubleshooting first.
a The machine monitor, engine controller, pump controller, and air conditioner controller are
connected via CAN communication.
[DAZQKR] is displayed on the operation screen of machine monitor in the following
cases. 1) and 2) of these will be covered here.
1. The air conditioner controller is receiving no power.
2. The air conditioner controller is broken.
3. No communication is possible between the air conditioner controller and the machine
monitor.
a For 3), see failure code [DAZQKR].
Turn the starting switch ON, and check whether failure code [DAZQKR] for an abnormality
in CAN communication is displayed. An abnormality in CAN communication refers to the
Related
state in which CAN communication between the air conditioner controller on the air
information
conditioner unit and the machine monitor is disabled.
Referring to "Parts and connectors layout", check fuse No. 14 (5A) in fuse box F01 for
breakage.
Ground cable of air conditioner is connected in machine wiring harness together with
electrical equipment of machine.
For each connector, see "Parts and connectors layout".
In cases where fuses are blown when the A/C switch is pressed, see "Troubleshooting for
compressor and refrigerant system."
Since T-adapter is not provided for the connector ACECU of the air conditioner controller
and the pin size is small, use the intermediate connector for troubleshooting (T-adapter is
also not provided for the intermediate connector, however, the pin size is larger).
When replacing the air conditioner wiring harness between connector ACECU of the air
conditioner controller and the intermediate connector, you must replace the entire air
conditioner unit.
No. Cause
Defective wiring
1
harness (ground)
2 Blown fuse
Defective wiring
3
harness
PC88MR-10
Procedure, measuring location, criteria, and remarks
1. Turn starting switch to OFF position.
2. Turn the battery disconnect switch to OFF position.
3. Disconnect connector AC02.
Between (1) (black) on harness side of connector
Resistance
AC02 and chassis ground
1. Turn starting switch to OFF position.
2. Referring to "Parts and connectors layout", check fuse No. 14 (5A) in fuse
box F01 for breakage.
a If fuse described in Related information is blown, replace it.
1. Turn starting switch to OFF position.
2. Turn the battery disconnect switch to OFF position.
3. Disconnect connector AC02.
4. Turn battery disconnect switch to ON position.
5. Turn starting switch to ON position.
Between connector AC02 (female) (4) (blue) and
Voltage
(1) (black)
A-1 Troubleshooting for power supply system (Air
conditioner does not operate)
80 Appendix
Max. 1 z
20 to 30 V
80-67