Yamaha YZ450F Owner's Service Manual page 307

Fault code
Symptom
2 Defective intake air pressure
sensor.
Fault code
Symptom
Fail-safe system
Diagnostic code No.
Diagnostic tool display
Procedure
Or- Probable cause of malfunc-
der tion and check
1 Connection of throttle posi-
tion sensor coupler.
Check the locking condition
of the coupler.
Disconnect the coupler, and
check the pins (for bent or
broken 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 (for bent or
broken terminals and locking
condition of the pins).
14
Intake air pressure sensor: hose system malfunction (clogged
or detached hose)
Execute the diagnostic mode.
(Code No. 03)
Atmospheric pressure at the
current altitude and weather
conditions is indicated.
0 m above sea level: About
101 kPa
1000 m above sea level:
About 90 kPa
2000 m above sea level:
About 80 kPa
3000 m above sea level:
About 70 kPa
15
Throttle position sensor: open or short circuit detected.
Able to start engine
Able to drive vehicle
01
Displays the throttle angle.
• 11–14 (throttle in fully closed position)
• 109–116 (throttle in fully opened position)
Check with throttle valves fully closed.
Check with throttle valves fully opened.
Maintenance job
Improperly connected 
Connect the coupler secure-
ly, or repair/replace the wire
harness.
Improperly connected 
Connect the coupler secure-
ly, or repair/replace the wire
harness.
8-17
FUEL INJECTION SYSTEM
Reinstatement method
Turn "ON" the switch on the
FI diagnostic tool sub-lead.
Fault code No. is not dis-
played  Repair is finished.
Fault code No. is displayed 
Go to next order.
Turn "ON" the switch on the
FI diagnostic tool sub-lead.
Fault code No. is not dis-
played  Repair is finished.
Fault code No. is displayed 
Go to next order.