Failure Code [Ca144] Coolant Sensor High Error - Komatsu WA250-6 Shop Manual

SEN03842-00

Failure code [CA144] Coolant sensor high error

Action code Failure code
E01
Contents of
• High voltage is detected in coolant temperature sensor signal circuit.
trouble
Action of
• Fixes engine coolant temperature and continues operation.
controller
Problem that
• Exhaust smoke becomes white
appears on
• Overheat prevention function does not function.
machine
• The input state (temperature) from the engine coolant temperature sensor can be checked with the
monitoring function (Code: ENGINE, 04104, COOLANT TEMP).
Related
• The input state (voltage) from the engine coolant temperature sensor can be checked with the moni-
information
toring function (Code: ENGINE, 04105, COOLANT TEMP).
• Method of reproducing failure code: Turn the starting switch ON.
Defective coolant tempera-
1 ture sensor
(Internal trouble)
Disconnection in wiring har-
ness
2
(Disconnection or defective
contact in connector)
Possible causes
and standard
value in normal
Short circuit in wiring har-
state
3 ness
(with another wiring harness)
Defective wiring harness
4
connector
5 Defective engine controller
14
40-320
Trouble
CA144
Causes
320 Troubleshooting by failure code (Display of code), Part 2
Failure code [CA144] Coolant sensor high error
Coolant sensor high error
(Engine controller system)
Standard value in normal state/Remarks on troubleshooting
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
COOLANT TEMP
Coolant temperature
(male)
Between (A) and (B)
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
Wiring harness between EC1 (female) (15) –
COOLANT TEMP (female) (B)
Wiring harness between EC1 (female) (38) –
COOLANT TEMP (female) (A)
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
Wiring harness among all pins between EC1
(female) (15) – EC1 (female)
(With all connectors of wiring harness dis-
connected)
Connecting parts among coolant temperature sensor, 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 carry out troubleshooting
without turning starting switch ON.
EC1 (female) Coolant temperature
Between (15) and
(38)
Resistance
0°C 30 – 37 kz
25°C 9.3 – 10.7 kz
50°C 3.2 – 3.8 kz
80°C 1.0 – 1.3 kz
95°C 700 – 800 z
Resis-
tance
Resis-
tance
Resis-
tance
Resistance
0°C 30 – 37 kz
25°C 9.3 – 10.7 kz
50°C 3.2 – 3.8 kz
80°C 1.0 – 1.3 kz
95°C 700 – 800 z
WA250, 250PZ-6
1
Max. 10z
Max. 10z
Min.
100 kz