Failure Code [Db2Qkr] Can2 Defective Communication (Engine Con) - Komatsu PC88MR-10 Shop Manual

Failure code [DB2QKR] CAN2 Defective Communication (Engine
Con)
(PC88MR-DB2QKR-400-A-Z0-A)
Action level Failure code
DB2QKR
L03
Machine monitor cannot recognize engine controller over CAN communication-2 line
Detail of
(KOMNET/c).
failure
Action of
Retains information at time of occurrence of failure.
controller
Information to be obtained from engine controller is not displayed and special functions
Problem on
that need information do not work. Or update of received data is stopped.
machine
(Failure codes and monitoring codes that are sent by engine controller)
Method of reproducing failure code: Turn starting switch to ON position.
Start of CAN communication is recognized by each controller when ACC signal of starting
switch is received.
If failure code [DB2RKR] is also displayed, engine controller may be defective (cause 2).
4 different failure codes, [DA2QKR], [DB2QKR], [D8AQKR], and [DAZQKR], are used for
defective CAN communication by CAN2, which are detected by machine monitor. When
all of these 4 failure codes are displayed, there may be a ground fault, short circuit, or hot
short in wiring harness (CAN communication circuit). In this case, check whether air
Related conditioner is operated (ON/OFF and air flow adjustment) from air conditioner operation
information screen since air conditioner is also controlled over CAN communication line.
a Air conditioner can be controlled even when failure code is displayed on screen. If air
conditioner is controlled, wiring harness (CAN communication line) does not have ground
fault, short circuit, or hot short circuit.
Since each controller and machine monitor are connected directly to battery, they are
supplied with power even after starting switch is turned to OFF position.
Since signal of active CAN communication line is pulse voltage, it cannot be measured by
using multimeter.
No. Cause
Defective fuse No. 15 or
1
No. 18 in fuse box F01
Defective engine
2
controller
Defective power supply
3
to engine controller
Defective CAN
terminating resistor
4
(internal open or short
circuit)
PC88MR-10
CAN2 Defective Communication (Engine Controller)
Failure
(Detected by machine monitor) (Machine monitor system)
Procedure, measuring location, criteria, and remarks
1. Turn starting switch to OFF position.
2. Remove fuses No. 15 and No. 18 from fuse box F01.
When fuse is blown, engine controller may have internal short circuit.
a If fuse is not blown, this check is not required.
1. Turn starting switch to OFF position.
2. Disconnect connector CE03 and connect T-adapter to male side.
Between CE03 (male) (1) and (21)
Resistance
Between CE03 (male) (11) and (31)
a Check ground terminal T12 for looseness and rust.
1. Turn starting switch to OFF position.
2. Disconnect connector CE03, and connect T-adapter to female side.
3. Turn starting switch to ON position.
a If any trouble is found, perform troubleshooting for failure code [CA441].
Between CE03 (female) (1) and (21)
Voltage
Between CE03 (female) (11) and (31)
1. Turn starting switch to OFF position.
2. Disconnect connectors CM02 and K02, and connect T-adapters to each
male side.
Between K02 (male) (A) and (B)
Resistance
Between CM02 (male) (7) and (9)
40 Troubleshooting
Troubleshooting by failure code (Display of code)
Min. 10 z
Min. 10 z
20 to 30 V
20 to 30 V
120 ± 12 z
120 ± 12 z
40-285