Failure Code [Ca145] Coolant Temperature Sensor Low Error - Komatsu PC88MR-10 Shop Manual

Failure code [CA145] Coolant Temperature Sensor Low Error

A-Z0-A)
Action level Failure code
L01 CA145
Detail of
Low voltage occurs in engine coolant temperature sensor signal circuit.
failure
Action of
Sets coolant temperature to fixed value (90°C) and runs engine.
controller
Engine startability is poor at low temperatures.
Problem on
Overheat prevention function does not work.
machine
Signal voltage from engine coolant temperature sensor can be checked with monitoring
function. (Code: 04105 (V))
Temperature sensed by engine coolant temperature sensor can be checked with
monitoring function. (Code: 04107 (°C))
Method of reproducing failure code: Turn starting switch to ON position.
Related
If temperature sensor connector is disconnected, failure code [CA144] for high error is
information
displayed in place of this failure code.
Drain approximately 10l l of coolant beforehand, because you may get scalded by
hot water spurting out from mounting location of coolant temperature sensor when
removing radiator cap during checking and replacing coolant temperature sensor.
No. Cause
Defective wiring harness
1
connector
Defective coolant
2
temperature sensor
Short circuit in wiring
3
harness
Ground fault in wiring
harness
4
(contact with ground
circuit)
Defective engine controller
5
PC88MR-10
Coolant Temperature 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.
1. Turn starting switch to OFF position.
2. Disconnect connector TWTR, and connect to socket to male side.
a Regard coolant temperature sensor as normal if its resistance is 700 z
to 37 kz when coolant temperature is min. 0°C.
Between TWTR (male) (A) and (B)
a Coolant temperature-Resistance
characteristics
Resis-
tance
Between TWTR (male) (B) and
ground
1. Turn starting switch to OFF position.
2. Disconnect connector J1 and connect T-adapter to female side.
Between J1 (female) (14) and (13) (Coolant
temperature: Min. 0°C)
Resis-
a Use Coolant temperature-Resistance
tance
characteristics table for check on cause 2
as resistance criteria.
1. Turn starting switch to OFF position.
2. Disconnect connectors J1 and TWTR, and connect T-adapter to female
side of connector J1.
Resis-
Between J1 (female) (14) and ground
tance
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)
0°C
25°C
50°C
80°C
95°C
Whole
coolant
tempera-
ture
range
(PC88MR-CA145-400-
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
Min. 1 Mz
700 z to 37 kz
Min. 1 Mz
40-139