Failure Code [Ca272] Pcv1 Open Circuit Error - Komatsu PC88MR-10 Shop Manual

40 Troubleshooting
Troubleshooting by failure code (Display of code)

Failure code [CA272] PCV1 Open Circuit Error

Action level Failure code
L03 CA272
Detail of
Open circuit occurs in supply pump control valve (SCV) circuit.
failure
Action of
controller
Problem on
Engine output lowers.
machine
Method of reproducing failure code: Turn starting switch to ON position.
Under normal conditions, pulse voltage of approx. 24 V is applied to SCV while engine is
running. However, it cannot be measured by using multimeter since it is pulse voltage.
Related
Since female connector alone is provided for "socket" used for troubleshooting of this
information
sensor, it is not connectable to female connector on sensor wiring harness side and thus
not usable for check of open circuit (not designed as T-adapter).
No. Cause
Defective wiring
1
harness connector
Defective supply pump
SCV
2
(internal open circuit)
Open or short circuit in
3
wiring harness
Ground fault in wiring
harness
4
(contact with ground
circuit)
Defective engine
5
controller
Circuit diagram related to SCV
40-156
PCV1 Open Circuit Error
Failure
(Engine controller system)
Procedure, measuring location, criteria, and remarks
1. See descriptions of wiring harness and connectors in "c: Electrical
equipment" in "Checks before troubleshooting" of "Related information on
troubleshooting", and check it.
2. Turn starting switch to ON position.
If this failure code is not displayed, wiring harness connector is defective.
a If this failure code is displayed, perform following checks.
1. Turn starting switch to OFF position.
2. Disconnect connector SCV and connect socket to male side.
Resistance Between SCV (male) (1) and (2)
1. Turn starting switch to OFF position.
2. Disconnect connector J1 and connect T-adapter to female side.
Between J1 (female) (30) and (40) (SCV
Resistance
resistance)
1. Turn starting switch to OFF position.
2. Disconnect connectors J1 and SCV.
3. Connect T-adapter to female side of connector J1.
Resistance Between J1 (female) (30) and ground
If no failure is found by above checks, engine controller is defective.
(Since this is an internal defect, troubleshooting cannot be performed.)
(PC88MR-CA272-400-A-Z0-A)
1 to 5 z
1 to 5 z
Min. 1 Mz
PC88MR-10