Yamaha WR450F Owner's Service Manual page 374

Fault code No.
Item
3 Wire harness continuity.
4 Installed condition of intake
air temperature sensor.
Check for looseness or
pinching.
5 Defective intake air tempera-
ture sensor.
6 Malfunction in ECU.
TIP
Before troubleshooting, disconnect the starter motor lead from the starter relay.
Fault code No.
Item
Fail-safe system
Diagnostic code No.
Diagnostic tool display
Procedure
Probable cause of malfunc-
Item
tion and check
1 The vehicle has overturned.
22
Intake air temperature sensor: open or short circuit detected.
Open or short circuit  Re-
place the wire harness.
Between intake air tempera-
ture sensor coupler and ECU
coupler.
black/blue–black/blue
brown/white–brown/white
Improperly installed sensor
 Reinstall or replace the
sensor.
Execute the diagnostic mode.
(Code No. 05)
When engine is cold:
Displayed temperature is
close to the ambient temper-
ature.
The displayed temperature is
not close to the ambient tem-
perature.  Check the intake
air temperature sensor.
Replace if defective.
Refer to "CHECKING THE
INTAKE AIR TEMPERA-
TURE SENSOR" on page 9-
80.
Replace the ECU.
30
Latch up detected.
Unable to start engine
Unable to drive vehicle
08
Lean angle sensor output voltage
• 0.4–1.4 (upright)
• 3.7–4.4 (overturned)
Remove the lean angle sensor and incline it more than 45 degrees.
Maintenance job
Raise the vehicle upright.
9-44
FUEL INJECTION SYSTEM
Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 4.
Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 5.
Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 6.
Confirmation of service
completion
Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 2.