Failure Code [Db2Qkr] Can2 Discon (Engine Con) - Komatsu PC200-8M0 Shop Manual

SEN06135-00

Failure code [DB2QKR] CAN2 Discon (Engine Con)

Action
Failure code
level
L03 DB2QKR
q
Machine monitor cannot recognize engine controller through CAN communication 2 line (KOM-
Detail of failure
NET/c).
Action of con-
q Holds information at the time of occurrence of failure.
troller
q
Information to be obtained from engine controller is not displayed and special functions that use
Problem on
them do not work. Or, received data is no longer updated. (such as failure codes and monitoring
machine
codes sent from engine controller)
q
Method of reproducing failure code: Turn starting switch to ON position.
q
Start of CAN communication is recognized by each controller when ACC signal of starting switch
is received.
q
Machine monitor indicates a CAN communication error in CAN2 with failure code [DA2QKR],
[DB2QKR], [D8AQKR], or [DAZQKR]. If all four of these failure code are displayed, harness (CAN
communication line) may have ground fault, short circuit, or hot short circuit. Since air conditioner
is also controlled via CAN communication, check whether air conditioner is operated (ON/OFF and
Related infor-
air flow adjustment) on air conditioner screen.
mation
a Air conditioner can be operated even when failure code is displayed on machine monitor screen. If
air conditioner is operated, there is no possibility of ground fault, short circuit, or hot short circuit in
wiring harness (CAN communication line).
q
Since each controller and machine monitor are connected to continuous power supply, they receive
continuous power even while starting switch is at OFF position.
q
Since active CAN communication line signal is pulse voltage, it cannot be measured by using mul-
timeter.
Cause
Defective fuses Nos. No.19 (30 A)
1 for (engine controller) in fuse box
F01
2 Defective engine controller
Improper power supply to engine
3
controller
Defective CAN terminating resis-
4 tor
(internal open or short circuit)
36
40-303
CAN 2 Disconnection 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.19 (30 A) from fuse box F01.
q
When fuse is blown, engine controller may have short circuit in it.
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-adapters to male side.
Between CE03 (male) (3) and (1)
a Check ground terminal T12 for looseness and rust.
1. Turn starting switch to OFF position.
2. Disconnect connector CE03, and connect T-adapters to female side.
3. Turn starting switch to ON position.
a If result is abnormal, perform troubleshooting for [CA441].
Between CE03 (female) (3) and (1)
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)
Between CM02 (male) (7) and (9)
303 Troubleshooting by failure code, Part 3
Failure code [DB2QKR] CAN2 Discon (Engine Con)
Resistance
Resistance 120 ± 12 z
Resistance 120 ± 12 z
PC200, 200LC, 220, 220LC-8M0
Min. 10 z
Voltage 20 to 30 V