Failure Code [Ca691] Intake Air Temperature Sensor High Error - Komatsu PC88MR-10 Shop Manual

Failure code [CA691] Intake Air Temperature Sensor High Error

400-A-Z0-A)
Action level Failure code
L01 CA691
Detail of
High voltage occurs in signal circuit of intake air temperature sensor.
failure
Action of
Sets intake air temperature to fixed value (25°C) and runs engine.
controller
Problem on
machine
Mass air flow sensor and intake air temperature sensor are integrated.
If sensor connector is disconnected, this failure code is displayed together with failure
Related
code [CA357].
information
Method of reproducing failure code: Turn starting switch to ON position.
No. Cause
Defective wiring
1
harness connector
Defective intake air
temperature sensor
2
(internal defect)
Open or short circuit in
wiring harness
3
(short circuit, wire
breakage or defective
contact of connector)
Hot short circuit in
4
wiring harness
Short circuit in wiring
5
harness
Defective engine
6
controller
PC88MR-10
Intake Air Temperature 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.
1. Turn starting switch to OFF position.
2. Disconnect connector P55 and connect T-adapter to male side.
Between P55 (male) (3) and (4)
Resistance
a Intake air temperature-Resistance
characteristics
1. Turn starting switch to OFF position.
2. Disconnect connector J1 and connect T-adapter to female side.
Resistance Between J1 (female) (6) and (22)
a Use Intake air temperature-Resistance characteristics table for check on
cause 2 as resistance criteria.
1. Turn starting switch to OFF position.
2. Disconnect connector P55.
3. Insert T-adapter into connector J1, or connect T-adapter to female side of
connector P55.
Between J1 (6) and (22) or between P55 (female)
Voltage
(4) and (3)
1. Turn starting switch to OFF position.
2. Disconnect connectors J1 and P55 and connect T-adapter to female side
of connector J1.
a Check by using multimeter in continuity mode.
Between J1 (female) (6) and each pin other than
Resistance
pin (6)
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)
(PC88MR-CA691-
-30°C 25 to 28 kz
5.5 to 6.1
0°C
kz
1.9 to 2.1
25°C
kz
1.1 to 1.2
40°C
kz
180 to 185
100°C
z
180 z to 28
kz
Max. 5.25 V
Min. 1 Mz
40-197