Code [689/Ca689] Eng. Ne Speed Sensor Error - Komatsu 114E-3 Series Shop Manual

SEN00460-01
E-44 Code [689/CA689] Eng. Ne Speed Sensor Error
Error code Failure code
689
Contents of trou-
• Abnormality occurred in signals from engine Ne speed sensor.
ble
Action of
• Controls Ne speed sensor with signals of Bkup speed sensor.
controller
Problem that • There is hunting from engine.
appears • Starting performance is poor
on machine • Engine output drops.
Related informa-
• Method of reproducing failure code: Start engine.
tion
Defective Ne speed sensor
1
power supply system
Defective engine Ne speed
2
sensor
Broken engine Ne speed sen-
3
sor or defective clearance
Broken rotation sensing fly-
4
wheel
Disconnection in wiring har-
ness (Disconnection in wiring
5
or defective contact in con-
nector)
Ground fault in wiring har-
Possible
6 ness (Short circuit with GND
causes and
circuit)
standard value
in normal state
Hot short (Short circuit with
7 5V, 24V circuit) in wiring har-
ness
Short circuit in wiring harness
8
(With another wiring harness)
Defective wiring harness con-
9
nector
32
Trouble Abnormality in engine Ne speed sensor
CA689
Causes Standard value in normal state/Remarks on troubleshooting
If failure code [CA238] is indicated simultaneously, carry out trouble-
shooting for it first.
a Prepare with starting switch OFF, then turn starting switch ON and
carry out troubleshooting.
CRANK SENSOR
Between (1) – (2)
Voltage is measured with wiring harness connected. Accordingly, if
voltage is abnormal, check wiring harness and controller, too, for
another cause of trouble, and then judge.
Inspect engine Ne speed sensor for breakage or clearance.
Inspect it for breakage directly.
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
Wiring harness between J1 (female) (27) –
CRANK SENSOR (female) (3)
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
Wiring harness between J1 (female) (27) –
CRANK SENSOR (female) (3) and chassis
ground
a Prepare with starting switch OFF, then turn starting switch ON and
carry out troubleshooting.
Wiring harness between J1 (female) (27) –
CRANK SENSOR (female) (3) and chassis
ground
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
Wiring harness between J1 (female) (27) –
CRANK SENSOR (female) (3) and J1
(female) (16) – CRANK SENSOR (female)
(1)
Wiring harness between J1 (female) (27) –
CRANK SENSOR (female) (3) and J1
(female) (48) – CRANK SENSOR (female)
(2)
Connecting parts among engine Ne speed 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
40 Troubleshooting
Power supply 4.75 – 5.25 V
Resis-
tance
Resis-
tance
Voltage
Resis-
tance
Resis-
tance
114E-3 Series
1
Voltage
Max. 10 z
Min.
100 kz
Max. 1 V
Min.
100 kz
Min.
100 kz