2011 YAMAHA YZ450F sensor

7-19
FUEL INJECTION SYSTEM
Fault code No. 16
Symptom Signal from throttle position sensor does not change.
Fail-safe system Able to start
Able to drive
Diagnostic code No. D01
FI diagnostic tool display • 15–19° (Fully closed position)
• 95–101° (Fully opened position)
Checking method• Check with throttle valves fully closed.
• Check with throttle valves fully open.
Item Item/components and probable cause Check or maintenance job Checking method
1 Installed condition of sensor.
• Make sure that the installation position is cor-
rect.
• Make sure that there are no problems with the
installation.Check that the sensor is installed
securely and that there are no
pinched leads. Check that the
ECU is installed securely and that
there are no pinched leads.
Incorrect installation → Reinstall
or repair.
Incorrect installation position →
Properly install.Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
operate the throttle.
After completing the above
operation, check whether a
fault code number is dis-
played.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 2.
2 Defective throttle position sensor. Execute the diagnostic mode (di-
agnostic code No. D01).
When throttle is fully closed: A
value of 15–19 is indicated.
When throttle is fully opened: A
value of 95–101 is indicated.
Displayed value is out of specifica-
tion → Replace.Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
operate the throttle.
After completing the above
operation, check whether a
fault code number is dis-
played.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 3.
3 Malfunction in ECU. Replace the ECU.

7-20
FUEL INJECTION SYSTEM
Make sure that the engine is completely cool before checking the coolant temperature sensor.
Fault code No. 21
Symptom Coolant temperature sensor signal is not received properly.
Fail-safe system Able to start
Able to drive
Diagnostic code No. D06
FI diagnostic tool display -20–150°C
Cold engine: Displayed temperature is close to the ambient temperature.
Warm engine: Displayed temperature is the current coolant temperature.
Checking method Check the coolant temperature.
Item Item/components and probable cause Check or maintenance job Checking method
1 Check the connection and locking condition of
the coolant temperature sensor coupler.
Disconnect the coupler and check the pins
(bent or broken terminals and locking condition
of the pins).Poor connection → Properly con-
nect, repair, or replace.Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 2.
2 Check the connection and locking condition of
the wire harness ECU coupler.
Disconnect the coupler and check the pins.
(bent or broken terminals and locking condition
of the pins)Poor connection → Properly con-
nect, repair, or replace.Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 3.
3 Continuity of harness Open or short circuit → Replace.
Between coolant temperature sen-
sor coupler and ECU coupler
(Brown–Brown)
(Black/Blue–Black/Blue)Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 4.
4 Installed condition of sensor. Check that the sensor is installed
securely and that there are no
pinched leads.Check that the ECU
is installed securely and that there
are no pinched leads.
Incorrect installation → Reinstall
or repair.Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 5.

7-21
FUEL INJECTION SYSTEM
Make sure that the engine is completely cool before checking the intake air temperature sensor.
5 Defective coolant temperature sensor. Execute the diagnostic mode (di-
agnostic code No. D06).
Cold engine: Displayed temper-
ature is close to the ambient
temperature.
Displayed value is incorrect → Re-
place. Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 6.
6 Malfunction in ECU. Replace the ECU.
Fault code No. 22
Symptom Intake air temperature sensor signal is not received properly.
Fail-safe system Able to start Able to drive
Diagnostic code No. D05
FI diagnostic tool display -20–100°C Cold engine: Displayed temperature is close to the ambient temperature.
Warm engine: Displayed temperature is approx imately 20°C higher than the ambient tem-
perature.
Checking method Check the temperature in the intake manifold. Item Item/components and probable cause Check or maintenance job Checking method
1 Check the connection and locking condition of the intake air temperature sensor coupler.
Disconnect the coupler and check the pins.
(bent or broken terminals and locking condition
of the pins) Poor connection
→ Properly con-
nect, repair, or replace. Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 2.
Fault code No. 21
Symptom Coolant temperature sensor signal is not received properly.
Fail-safe system Able to start
Able to drive
Diagnostic code No. D06
FI diagnostic tool display -20–150°C Cold engine: Displayed temperature is close to the ambient temperature.
Warm engine: Displayed temperature is the current coolant temperature.
Checking method Check the coolant temperature. Item Item/components and probable cause Check or maintenance job Checking method

7-22
FUEL INJECTION SYSTEM
2 Check the connection and locking condition of the wire harness ECU coupler.
Disconnect the coupler and check the pins.
(bent or broken terminals and locking condition
of the pins) Poor connection
→ Properly con-
nect, repair, or replace. Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item
3.
3 Continuity of harness Open or short circuit → Replace.
Between the intake air tempera-
ture sensor coupler and ECU cou-
pler.
(Brown/White–Brown/White)
(Black/Blue–Black/Blue) Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item
4.
4 Installed condition of sensor. Check that the sensor is installed securely and that there are no
pinched leads.Check that the ECU
is installed securely and that there
are no pinched leads.
Incorrect installation → Reinstall
or repair. Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item
5.
5 Defective intake temperature sensor. Execute the diagnostic mode (di- agnostic code No. D05).Cold engine: Displayed temper-
ature is close to the ambient
temperature.
Displayed value is incorrect → Re-
place. Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 6.
6 Malfunction in ECU. Replace the ECU. Fault code No. 22
Symptom Intake air temperature sensor signal is not received properly.
Fail-safe system Able to start Able to drive
Diagnostic code No. D05
FI diagnostic tool display -20–100°C Cold engine: Displayed temperature is close to the ambient temperature.
Warm engine: Displayed temperature is approx imately 20°C higher than the ambient tem-
perature.
Checking method Check the temperature in the intake manifold. Item Item/components and probable cause Check or maintenance job Checking method

7-23
FUEL INJECTION SYSTEM
Fault code No. 23
Symptom Atmospheric pressure sensor signal is not received properly.
Fail-safe system Able to start
Able to drive
Diagnostic code No. D02
FI diagnostic tool display Atmosphere
Checking method Measure the atmospheric pressure.
Item Item/components and probable cause Check or maintenance job Checking method
1 Check the connection and locking condition of
the atmospheric pressure sensor coupler.
Disconnect the coupler and check the pins.
(bent or broken terminals and locking condition
of the pins)Poor connection → Properly con-
nect, repair, or replace.Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 2.
2 Check the connection and locking condition of
the wire harness ECU coupler.
Disconnect the coupler and check the pins.
(bent or broken terminals and locking condition
of the pins)Poor connection → Properly con-
nect, repair, or replace.Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 3.
3 Continuity of harness Open or short circuit → Replace.
Between atmospheric pressure
sensor coupler and ECU coupler.
(Black/Blue–Black/Blue)
(Pink–Pink)
(Blue–Blue)Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 4.
4 Installed condition of sensor. Check that the sensor is installed
securely and that there are no
pinched leads.Check that the ECU
is installed securely and that there
are no pinched leads.
Incorrect installation → Reinstall
or repair.Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 5.

7-24
FUEL INJECTION SYSTEM
5 Defective atmospheric pressure sensor. Execute the diagnostic mode (di-
agnostic code No. D02).
When the engine is stopped,
displays the atmospheric pres-
sure according to the elevation
and weather.
0 m above 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
Displayed value is incorrect → Re-
place.Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 6.
6 Malfunction in ECU. Replace the ECU. Fault code No. 23
Symptom Atmospheric pressure sensor signal is not received properly.
Fail-safe system Able to start
Able to drive
Diagnostic code No. D02
FI diagnostic tool display Atmosphere
Checking method Measure the atmospheric pressure.
Item Item/components and probable cause Check or maintenance job Checking method

7-25
FUEL INJECTION SYSTEM
Fault code No. 30
Symptom Turnover of vehicle
Fail-safe system Able to start
Unable to drive
Diagnostic code No. D08
FI diagnostic tool display Lean angle sensor
• 1.0 V (Upright)
• 4.0 V (Overturned)
Checking method Remove the ECU and incline it 45° or more.
Item Item/components and probable cause Check or maintenance job Checking method
1 The vehicle has overturned. Raise the vehicle upright. Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item
2.
2 Installed condition of ECU.
•Make sure that the installation position is cor-
rect.Check that the sensor is installed
securely and that there are no
pinched leads.Check that the ECU
is installed securely and that there
are no pinched leads.
Incorrect installation → Reinstall
or repair.
Incorrect installation position →
Properly install.Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 3.
3 Defective lean angle sensor. Execute the diagnostic mode (di-
agnostic code No. D30).
Upright: 1.0 V
Overturned: 4.0 V
Displayed value is incorrect → Re-
place the ECU.Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 4.
4 Malfunction in ECU. Replace the ECU.

7-27
FUEL INJECTION SYSTEM
4 Installed condition of ignition coil Check that the sensor is installed
securely and that there are no
pinched leads.Check that the ECU
is installed securely and that there
are no pinched leads.
Incorrect installation → Reinstall
or repair.Start the engine and let it
idle for approximately 5
seconds.
After completing the above
operation, check whether a
fault code number is dis-
played.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 5.
5 Defective ignition coil. (test the primary coils for
continuity)Defective → Replace.
Refer to "CHECKING THE IGNI-
TION COIL".Start the engine and let it
idle for approximately 5
seconds.
After completing the above
operation, check whether a
fault code number is dis-
played.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 6.
6 Malfunction in ECU. Execute the diagnostic mode (di-
agnostic code No. D30).
No spark → Replace the ECU. Fault code No. 33
Symptom Ignition system circuit signal is not received properly.
Fail-safe system Unable to start
Unable to drive
Diagnostic code No. D30
FI diagnostic tool display Actuates the ignition coil for five times every second.
The "WARNING" LED on the FI diagnostic tool comes on each time the ignition coil is ac-
tuated.
Checking methodCheck the spark five times.
• Connect an ignition checker.
Item Item/components and probable cause Check or maintenance job Checking method