Code [123/Ca123] Charge Air Press Sensor Low Error - Komatsu 114E-3 Series Shop Manual

SEN00459-01
E-4 Code [123/CA123] Charge Air Press Sensor Low Error
Error code Failure code
123
Contents of
• Low voltage is detected in pressure signal circuit of boost pressure sensor and temperature sensor.
trouble
Action of con-
• Fixes charge pressure (101 kPa {1.03 kg/cm
troller
Problem that
appears on • Engine output drops.
machine
Related infor-
• Method of reproducing failure code: Starting switch ON.
mation
Defective sensor power sup-
1
ply 2 system
Defective [pressure signal
2 circuit] of boost pressure
sensor, temperature sensor
Ground fault in wiring har-
3 ness (Short circuit with GND
circuit)
Possible causes
and standard
value in normal
state
Short circuit in wiring har-
4 ness (With another wiring
harness)
Defective wiring harness
5
connector
6 Defective engine controller
6
Trouble
CA123
Causes
Abnormally low level in charge pressure sensor
2 }) and continues operation.
Standard value in normal state/Remarks on troubleshooting
If failure code [CA187] is indicated simultaneously, carry out trouble-
shooting for it first.
a Prepare with starting switch OFF, then turn starting switch ON
and carry out troubleshooting.
BOOST PRESS & IMT
Between (1) – (4)
Voltage is measured with wiring harness connected. Accordingly, if
voltage is abnormal, check wiring harness and controller, too, for
another cause of trouble, and then judge.
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
Wiring harness between J1 (female) (44) –
BOOST PRESS & IMT (female) (1)
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
Wiring harness between J1 (female) (44) –
BOOST PRESS & IMT (female) (1) and
between J1 (female) (47) – BOOST PRESS
& IMT (female) (4)
Connecting parts among boost pressure sensor, temperature sen-
sor, engine wiring harness, and engine controller are suspected.
Inspect them directly.
• Loose connector, broken lock, broken seal
• Corrosive, bent, broken, forced-in, or extended pin
• Humidity in connector, entry of dirt or dust, poor insulation
a Prepare with starting switch OFF, then turn starting switch ON
and carry out troubleshooting.
J1
Between (37) – (47)
40 Troubleshooting
Power supply 4.75 – 5.25 V
Resis-
tance
Resis-
tance
Power supply 4.75 – 5.25 V
114E-3 Series
1
Voltage
Min.
100 kz
Min.
100 kz
Voltage