Failure Code [Ca144] Coolant Temp Sens High Error - Komatsu PC200-8M0 Shop Manual

SEN06133-00

Failure code [CA144] Coolant Temp Sens High Error

Action
Failure code
level
L01 CA144
q
Detail of failure High voltage appears in signal circuit of coolant temperature sensor .
Action of con-
q
Takes coolant temperature to be at fixed value and allows engine to run.
troller
q
Problem on Engine does not start easily at low temperature.
machine q Overheat prevention function does not work.
q
Input voltage from engine coolant temperature sensor can be checked with monitoring function.
(Code: 04105 (V))
q
Temperature sensed by engine coolant temperature sensor can be checked with monitoring func-
tion.
Related infor- (Code: 04107 (°C))
q
mation Method of reproducing failure code: Turn starting switch to ON position.
q
This failure code is displayed if temperature sensor connector is disconnected.
q
Because troubleshooting "socket" for this sensor features female connector alone, it is not connect-
able to female connector of sensor wiring harness, and thus not usable for checking open circuit
(not designed as a T-adapter).
Cause
Defective wiring harness connec-
1
tor
Defective coolant temperature
2
sensor
Open or short circuit in wiring har-
3
ness
4 Defective engine controller
28
40-301
Coolant Temperature 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.
1. Turn starting switch to OFF position.
2. Disconnect connector COOLANT TEMP, and connect socket to male side.
a If coolant temperature sensor has resistance of 700 z - 37 kz with coolant
temperature above 0 °C, regard coolant temperature sensor as normal.
Between COOLANT
TEMP (male) (A) and (B)
a Coolant temperature
-Resistaure charac-
teristics
1. Turn starting switch to OFF position.
2. Disconnect connector ECM and connect T-adapters to female side.
Between ECM (female) (15) and (38) (Coolant tem-
perature: Min. 0°C)
a Use "Coolant temperature-Resistance charac-
teristics" table shown above as resistance crite-
ria.
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

Failure code [CA144] Coolant Temp Sens High Error

0 °C Resistance
25 °C Resistance
50 °C Resistance
80 °C Resistance
95 °C Resistance
PC200, 200LC, 220, 220LC-8M0
30 to 37 kz
9.3 to 10.7 kz
3.2 to 3.8 kz
1.0 to 1.3 kz
700 to 800 z
Resis-
700 z to 37 kz
tance