Failure Code [Ca123] Charge Air Pressure Sensor Low Error - Komatsu PC88MR-10 Shop Manual

Failure code [CA123] Charge Air Pressure Sensor Low Error

Z0-A)
Action level Failure code
L03 CA123
Detail of
Low voltage occurs in charge (boost) pressure sensor signal circuit.
failure
Sets charge (boost) pressure to fixed value (400 kPa {4.1 kg/cm
Action of
Closes EGR valve and opens variable flow turbocharger fully.
controller
Limits engine output and runs engine.
Acceleration performance of engine drops.
Problem on
Engine output lowers.
machine
Signal voltage from charge pressure sensor (boost pressure sensor) can be checked with
monitoring function. (Code: 36501 (V))
Boost pressure sensed by charge (boost) pressure sensor can be checked with
monitoring function. (Code: 36500 (kPa))
Related
Method of reproducing failure code: Turn starting switch to ON position.
information
Since female connector alone is provided for "socket" used for troubleshooting of this
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).
This failure code appears if sensor connector is disconnected.
No. Cause
Defective wiring
1
harness connector
Defective power supply
system of charge
2
pressure sensor (boost
pressure sensor)
Short circuit in wiring
3
harness
Ground fault in wiring
harness
4
(contact with ground
circuit)
Open circuit in wiring
harness
5
(wire breakage or
defective contact of
connector)
Defective charge
6
(boost) pressure sensor
Defective engine
7
controller
*: Refer to "Troubleshooting method for open circuit in wiring harness of pressure sensor system" of "General
information on troubleshooting".
PC88MR-10
Charge Air Pressure Sensor Low 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.
If failure code [CA187] or [CA227] is also displayed, perform troubleshooting
for it first.
1. Turn starting switch to OFF position.
2. Disconnect connectors J1 and TMAP, and connect T-adapter to female
side of connector J1.
Resistance Between J1 (female) (15) and (59)
1. Turn starting switch to OFF position, then perform troubleshooting.
2. Disconnect connectors J1 and TMAP, and connect T-adapter to female
side of connector J1.
Resistance Between J1 (female) (15) and ground
If no failure is found by above checks, wiring harness probably has open
circuit. (*)
a If no failure is found by checks on causes 1 to 5 and failure is found by
check on cause 6, sensor is defective.
1. Turn starting switch to OFF position.
2. Insert T-adapter into connector J1.
3. Turn starting switch to ON position.
Voltage Between J1 (15) and (59)
If no failure is found by above checks, engine controller is defective.
(Since this is an internal defect, troubleshooting cannot be performed.)
40 Troubleshooting
Troubleshooting by failure code (Display of code)
2 }) and runs engine.
(PC88MR-CA123-400-A-
Min. 1 Mz
Min. 1 Mz
Sensor
0.3 to 4.7 V
output
40-131