Failure Code [Ca122] Chg Air Press Sensor High Error - Komatsu PC200-8M0 Shop Manual

SEN06133-00

Failure code [CA122] Chg Air Press Sensor High Error

Action
Failure code
level
L03 CA122
q
Detail of failure High voltage appears in 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.
Related infor-
(Code: 36500 (kPa))
mation
q
Method of reproducing failure code: Turn starting switch to ON position.
q
If sensor connector is disconnected, code [CA123] for "Low Error" is displayed, even in normal con-
dition.
Cause
Defective wiring harness connec-
1
tor
Defective sensor power supply 2
2
line
Defective boost pressure & tem-
3
perature sensor
4 Short circuit in wiring harness
Hot short circuit in wiring harness
5
(Contact with 24 V circuit)
6 Defective engine controller
20
40-301

Failure code [CA122] Chg Air Press Sensor High Error

Charge Air Press Sensor High 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 [CA227] is also displayed, perform troubleshooting for it first.
1. Turn starting switch to OFF position.
2. Disconnect connector BOOST PRESS & IMT.
3. Turn starting switch to ON position.
If failure code changes from [CA122] to [CA123] ,boost pressure sensor is
defective.
a Failure code [CA153] for temperature sensor is displayed at the same time.
Ignore this failure code since it appears because of disconnection of
sensor.
q
Reference
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)
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) (37) and (44)
1. Turn starting switch to OFF position.
2. Disconnect connector BOOST PRESS & IMT, and connect T-adapter to
connector ECM.
3. Turn starting switch to ON position (with connector BOOST PRESS & IMT
disconnected).
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
Sensor out-
Voltage
put
Resistance Min. 100 kz
Voltage
PC200, 200LC, 220, 220LC-8M0
0.3 to 4.7 V
Max. 1 V