Failure Code [Ca123] Chg Air Press Sensor Low Error - Komatsu PC200-8M0 Shop Manual

SEN06133-00

Failure code [CA123] Chg Air Press Sensor Low Error

Action
Failure code
level
L03 CA123
q
Detail of failure Low voltage appears in pressure signal circuit of charge (boost) pressure & temperature sensor.
Action of con-
q
Takes boost pressure to be at fixed value and allows engine to run.
troller
Problem on
q
Engine output lowers.
machine
q
Input voltage from boost pressure sensor can be checked with monitoring function.
(Code: 36501 (V))
q
Boost pressure sensed by boost pressure sensor can be checked with function.
(Code: 36500 (kPa))
Related infor-
q
Method of reproducing failure code: Turn starting switch to ON position.
mation
q
Since troubleshooting "socket" for this sensor features female connector alone, it is not usable for
checking open circuit in wiring harness and voltage at sensor connector (not designed as a
T-adapter).
q
If sensor connector is disconnected, this failure code is displayed.
Cause
Defective wiring harness connec-
1
tor
Defective power supply system of
2 charge pressure sensor (boost
pressure sensor)
3 Short circuit in wiring harness
Ground fault in wiring harness
4
(contact with ground circuit)
5 Open circuit in wiring harness
Defective boost pressure & tem-
perature sensor
6
(improper input voltage to engine
controller)
7 Defective engine controller
*: See "Troubleshooting method for open circuit in wiring harness of pressure sensor system" of "General in-
formation on troubleshooting".
22
40-301

Failure code [CA123] Chg Air Press Sensor Low Error

Charge Air Pressure Sensor Low Error
Failure
(Engine controller system)
Procedure, measuring location, criteria and remarks
See descriptions of wiring harness and connectors in "c: Electrical equipment"
in "Checks before troubleshooting" of "General information on troubleshoot-
ing", and check them.
If failure code [CA187] or [CA227] is displayed, perform troubleshooting for it
first.
1. Turn starting switch to OFF position.
2. Disconnect connectors CAM SENSOR, FUEL RAIL PRESS, BOOST
PRESS & IMT and ECM.
3. Connect T-adapters to female side of ECM.
Between ECM (female) (37) and (47)
Between ECM (female) (44) and (47)
1. Turn starting switch to OFF position.
2. Disconnect connectors ECM and BOOST PRESS & IMT, and connect
T-adapter to female side of ECM.
Between ECM (female) (44) and ground
If no failure is found by above checks, there may be open circuit in wiring har-
ness. (*)
a If no failure is found by checks on causes 1 to 5 and check result on cause
6 is abnormal, sensor is defective.
1. Turn starting switch to OFF position.
2. Insert T-adapters to connector ECM.
3. Turn starting switch to ON position.
Between ECM (44) and (47)
If no failure is found by above checks, engine controller is defective. (Since
this is an internal defect, troubleshooting cannot be performed.)
301 Troubleshooting by failure code, Part 1
Resistance Min. 100 kz
Resistance Min. 100 kz
Resistance Min. 100 kz
Sensor out-
Voltage
put
PC200, 200LC, 220, 220LC-8M0
0.3 to 4.7 V