Failure Code [Ca122] Charge Air Pressure Sensor High Error - Komatsu PC88MR-10 Shop Manual

Failure code [CA122] Charge Air Pressure Sensor High Error

A-Z0-A)
Action level Failure code
L03 CA122
Detail of
High 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).
If sensor connector is disconnected, failure code [CA123] for "Low Error" is displayed
even in normal condition.
No. Cause
Defective wiring
1
harness connector
Defective sensor power
2
supply system
Defective charge
3
(boost) pressure sensor
Short circuit in wiring
4
harness
Hot short circuit in
5
wiring harness
PC88MR-10
Charge Air Pressure Sensor High 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 connector TMAP.
3. Turn starting switch to ON position.
If failure code changes from [CA122] to [CA123], charge (boost) pressure
sensor is defective.
a Other failure code [CA153] for temperature sensor is also displayed.
Ignore this code since this is displayed due to disconnection of sensor
connector.
Reference
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)
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 (60)
1. Turn starting switch to OFF position.
2. Disconnect connector TMAP, and insert T-adapter into connector J1.
3. Turn starting switch ON (with connector TMAP disconnected).
Voltage Between J1 (15) and (59)
40 Troubleshooting
Troubleshooting by failure code (Display of code)
2 }) and runs engine.
(PC88MR-CA122-400-
Sensor
0.3 to 4.7 V
output
Min. 1 Mz
Max. 1 V
40-129