Yamaha YZ450F Owner's Service Manual page 208

Fault code No.
Symptom
Fail-safe system
Diagnostic code No.
FI diagnostic tool display
Checking method
Item Item/components and probable cause
2 Check the connection and locking condition of
the wire harness ECU coupler.
Disconnect the coupler and check the pins.
(bent or broken terminals and locking condition
of the pins)
3 Continuity of harness
4 Installed condition of sensor.
5 Defective intake temperature sensor.
6 Malfunction in ECU.
22
Coolant temperature sensor signal is not received properly.
Able to start
Able to drive
D05
-20–100°C
Cold engine: Displayed temperature is close to the ambient temperature.
Warm engine: Displayed temperature is approximately 20°C higher than the ambient tem-
perature.
Check the temperature in the intake manifold.
FUEL INJECTION SYSTEM
Check or maintenance job
Poor connection → Properly con-
nect, repair, or replace.
Open or short circuit → Replace.
Between the intake air tempera-
ture sensor coupler and ECU cou-
pler.
(Brown/White–Brown/White)
(Black/Blue–Black/Blue)
Check that the sensor is installed
securely and that there are no
pinched leads.Check that the ECU
is installed securely and that there
are no pinched leads.
Incorrect installation → Reinstall
or repair.
Execute the diagnostic mode (di-
agnostic code No. D05).
Cold engine: Displayed temper-
ature is close to the ambient
temperature.
Displayed value is incorrect → Re-
place.
Replace the ECU.
7-22
Checking method
Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item
3.
Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item
4.
Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item
5.
Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 6.