Yamaha YZ450FN 2022, Owner'S Service Manual, Page: 304 / 366

FUEL INJECTION SYSTEM
8-23
Fault code No. 15
TIP
Before troubleshooting, disconnect the starter motor lead from the starter relay.
Fault code No. 15
Item Throttle position sensor: open or short circuit detected.
Fail-safe system
Able to start engine
Able to drive vehicle
Diagnostic code No.
01
Diagnostic tool display
Displays the throttle angle.
•
11–14 (throttle in fully closed position)
•
86–92 (throttle in fully opened position)
Procedure
•
Check with throttle fully closed.
•
Check with throttle fully opened.
Item
Probable cause of malfunc-
tion and check
Maintenance job
Confirmation of service com-
pletion
1 Connection of throttle position
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.
Start switch to ON (main relay
ON), and then check the condi-
tion of the fault code using the
malfunction mode of the
Yamaha diagnostic tool.
Condition is “Recovered”

Go
to item 8 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.
Start switch to ON (main relay
ON), and then check the condi-
tion of the fault code using the
malfunction mode of the
Yamaha diagnostic tool.
Condition is “Recovered”

Go
to item 8 and finish the service.
Condition is “Detected”

Go to
item 3.
3 Wire harness continuity. Open or short circuit

Replace
the wire harness.
Between throttle position sensor
coupler and ECU coupler.
yellow–yellow
blue–blue
black/blue–black/blue
Start switch to ON (main relay
ON), and then check the condi-
tion of the fault code using the
malfunction mode of the
Yamaha diagnostic tool.
Condition is “Recovered”

Go
to item 8 and finish the service.
Condition is “Detected”

Go to
item 4.
4 Mounted condition of throttle
position sensor.
Check for looseness or pinch-
ing.
Check the mounted position for
correctness.
Improperly mounted sensor

Remount or replace the sensor.
Refer to “ADJUSTING THE
THROTTLE POSITION SEN-
SOR” on page 7-8.
Start switch to ON (main relay
ON), and then check the condi-
tion of the fault code using the
malfunction mode of the
Yamaha diagnostic tool.
Condition is “Recovered”

Go
to item 8 and finish the service.
Condition is “Detected”

Go to
item 5.