Yamaha WR250F Owner's Service Manual page 373

Fault code No.
Item
2 Defective intake air pressure
sensor.
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 throttle posi-
tion 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).
14
Intake air pressure sensor: hose system malfunction (clogged
or detached hose).
Execute the diagnostic mode.
(Code No. 03)
When engine is stopped:
Atmospheric pressure at the
current altitude and weather
conditions is indicated.
At sea level: Approx. 101 kPa
1000 m above sea level: Ap-
prox. 90 kPa
2000 m above sea level: Ap-
prox. 80 kPa
3000 m above sea level: Ap-
prox. 70 kPa
When engine is cranking:
Make sure that the indication
value changes.
The value does not change
when engine is cranking. 
Check the intake air pressure
sensor.
Replace if defective.
Refer to "CHECKING THE
INTAKE AIR PRESSURE
SENSOR" on page 9-80.
15
Throttle position sensor: open or short circuit detected.
Able to start engine
Able to drive vehicle
01
Throttle position sensor signal
• 11–14 (fully closed position)
• 109–116 (fully open position)
• Check with throttle valve fully closed.
• Check with throttle valve fully open.
Maintenance job
Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.
9-39
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.