Yamaha WR450F Owner's Service Manual page 378

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 Connection of lean angle
sensor coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).
2 Connection of wire harness
ECU coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).
3 Wire harness continuity.
4 Defective lean angle sensor.
5 Malfunction in ECU.
41
Lean angle sensor: open or short circuit detected.
Unable to start engine
Able 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
Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.
Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.
Open or short circuit  Re-
place the wire harness.
Between lean angle sensor
coupler and ECU coupler.
blue–blue
yellow/green–yellow/green
black/blue–black/blue
Execute the diagnostic mode.
(Code No. 08)
Replace if defective.
Refer to "CHECKING THE
LEAN ANGLE SENSOR" on
page 9-75.
Replace the ECU.
9-48
FUEL INJECTION SYSTEM
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.
Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 3.
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.