Failure Code [Ca689] Engine Ne Speed Sensor Error - Komatsu PC88MR-10 Shop Manual

Failure code [CA689] Engine NE Speed Sensor Error

Action level Failure code
L01 CA689
Detail of
Engine Ne speed sensor signal is abnormal.
failure
Action of
Controls engine by using signals from engine Bkup speed sensor.
controller
Running engine stops (when Bkup speed sensor is also defective).
Problem on
Stopped engine cannot be restarted (when Bkup speed sensor is also defective).
machine
Method of reproducing failure code: Start engine.
Since interior portion of speed sensor is configured with hall sensor and electronic circuit
rather than coil, measurements of speed sensor resistance by using mulitimeter cannot
be used to determine whether sensor is normal or not.
Related
Since speed sensor output is pulse voltage of 5 V in normal state, multimeter is not usable
information
for measurement.
Wheel (W) is mounted inside of crankshaft vibration damper and has holes for speed
sensing. Ne speed sensor detects rotating holes, and both engine speed and phase are
calculated by the engine controller.
No. Cause
Defective wiring
1
harness connector
Defective Ne speed
sensor power supply
2
system
Breakage or improper
installation (loosened)
3
of engine Ne speed
sensor
Damage or poor (loose)
mounting of wheel for
4
speed sensing
Defective Ne speed
sensor power supply
5
input
Open circuit in wiring
harness
6
(wire breakage or
defective contact of
connector)
Short circuit in wiring
7
harness
PC88MR-10
Engine NE Speed Sensor 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.
If failure code [CA238] is also displayed, perform troubleshooting for it first.
Engine Ne speed sensor may be broken or improperly installed (loose).
Check it.
Check wheel (W) for speed sensing directly as it may be damaged or loosely
mounted.
1. Turn starting switch to OFF position.
2. Disconnect connector NE, and connect T-adapter to female side.
3. Turn starting switch to ON position.
Voltage Between NE (female) (1) and (2)
1. Turn starting switch to OFF position.
2. Disconnect connectors J1 and NE, and connect T-adapters to each female
side.
If no failure is found by check on cause 4, this
check is not required.
Between J1 (female) (36) and NE (female) (1)
If no failure is found by check on cause 4, this
Resistance
check is not required.
Between J1 (female) (37) and NE (female) (2)
Between J1 (female) (26) and NE (female) (3)
1. Turn starting switch to OFF position.
2. Disconnect connectors J1 and NE and connect T-adapter to either female
side.
Between J1 (female) (36) and (26), or between NE
(female) (1) and (3)
Resistance
Between J1 (female) (37) and (26), or between NE
(female) (2) and (3)
40 Troubleshooting
Troubleshooting by failure code (Display of code)
(PC88MR-CA689-400-A-Z0-A)
supply input
Power
4.75 to 5.25
V
Max. 1 z
Max. 1 z
Max. 1 z
Min. 1 Mz
Min. 1 Mz
40-195