Yamaha WR250F 2021 - Page 342

FUEL INJECTION SYSTEM
8-41
Fault code No. 22
TIP
• Make sure that the machine is completely cold before checking the intake air temperature sensor.
• Before troubleshooting, disconnect the starter motor lead from the starter relay.
Fault code No. 22
Item Intake air temperature sensor: open or short circuit detected.
Fail-safe system
Able to start engine
Able to drive vehicle
Diagnostic code No. 05
Diagnostic tool display Displays the intake air temperature.
Procedure
Compare the actually measured intake air temperature with the Yamaha
diagnostic tool display value.
Item
Probable cause of malfunc-
tion and check
Maintenance job
Confirmation of service com-
pletion
1 Connection of intake air temper-
ature sensor coupler.
Check the locking condition of
the coupler.
Disconnect the coupler, and
check the pins (for bent or bro-
ken terminals and locking condi-
tion of the pins).
Improperly connected  Con-
nect the coupler securely, or
repair/replace the wire harness.
Push the start switch (main
relay ON), and then check the
condition of the fault code using
the malfunction mode of the
Yamaha diagnostic tool.
Condition is “Recovered”  Go
to item 7 and finish the service.
Condition is “Detected”  Go to
item 2.
2 Connection of wire harness
ECU coupler.
Check the locking condition of
the coupler.
Disconnect the coupler, and
check the pins (for bent or bro-
ken terminals and locking condi-
tion of the pins).
Improperly connected  Con-
nect the coupler securely, or
repair/replace the wire harness.
Push the start switch (main
relay ON), and then check the
condition of the fault code using
the malfunction mode of the
Yamaha diagnostic tool.
Condition is “Recovered”  Go
to item 7 and finish the service.
Condition is “Detected”  Go to
item 3.
3 Wire harness continuity. Open or short circuit  Replace
the wire harness.
Between intake air temperature
sensor coupler and ECU cou-
pler.
brown/white–brown/white
black/blue–black/blue
Push the start switch (main
relay ON), and then check the
condition of the fault code using
the malfunction mode of the
Yamaha diagnostic tool.
Condition is “Recovered”  Go
to item 7 and finish the service.
Condition is “Detected”  Go to
item 4.
4 Mounted condition of intake air
temperature sensor.
Check for looseness or pinch-
ing.
Check the mounted position for
correctness.
Improperly mounted sensor 
Remount or replace the sensor.
Push the start switch (main
relay ON), and then check the
condition of the fault code using
the malfunction mode of the
Yamaha diagnostic tool.
Condition is “Recovered”  Go
to item 7 and finish the service.
Condition is “Detected”  Go to
item 5.