2011 YAMAHA YZ450F sensor

7-10
FUEL INJECTION SYSTEM
SETTING THE DIAGNOSTIC MODE
When the FI diagnostic tool is set to
the diagnostic mode, the sensor out-
put data can be displayed and the op-
eration of the actuators can be
checked.
1. While pressing the "MODE" but-
ton, set the switch on the FI diag-
nostic tool sub-wire harness to
"ON".
• When the switch on the FI diagnos-
tic tool sub-wire harness is set to
"ON", make sure that "Waiting for
connection" is displayed on the
LCD of the FI diagnostic tool.
• "DIAG" appears on the LCD of the
FI diagnostic tool.
2. Select the diagnostic mode "DI-
AG" by pressing the "UP" button.
3. After selecting "DIAG", press the
"MODE" button.
4. Select the diagnostic code num-
ber corresponding to the fault
code number by pressing the
"UP" and "DOWN" buttons.
• Select the diagnostic code number
corresponding to the fault code
number by pressing the "UP" and
"DOWN" buttons.
• To decrease the selected diagnos-
tic code number, press the "DOWN"
button. Press the "DOWN" button
for 1 second or more to automati-
cally decrease the diagnostic code
numbers.
• To increase the selected diagnostic
code number, press the "UP" but-
ton. Press the "UP" button for 1 sec-
ond or more to automatically
increase the diagnostic code num-
bers.
5. Check the operation of the sensor
or actuator.
• Sensor display: Data indicating
the sensor status is displayed on
the LCD of the FI diagnostic tool.
• Actuator operation: Press the
"MODE" button to operate the ac-
tuator.
6. Set the switch on the FI diagnostic
tool sub-wire harness to "OFF".

7-11
FUEL INJECTION SYSTEM
SENSOR OPERATION TABLE
Diagnos-
tic code
No.ItemActuation or
displayChecking methodActuation or LCD standard display
values
D01 Throttle angle DisplayDisplays the throttle angle. 0–125°
Check with throttle fully closed. When throttle is fully closed:15–19°
Check with throttle fully open. When throttle is fully
opened:95–101 °
D02 Atmosphere DisplayDisplays the atmospheric pres-
sure.
• Measure the atmospheric pres-
sure.0–126 kPa
Displays the atmospheric pressure
according to the elevation and
weather.
Example
0 m above sea level: Approx: 101
kPa
3000 m above sea level:Approx: 70
kPa
D03 Intake air pressure DisplayDisplays the intake air pressure.
• Check the intake manifold pres-
sure.
• Check that the intake air pres-
sure changes while the engine is
being cranked.0–126 kPa
While the engine is stopped: Dis-
plays the atmospheric pressure ac-
cording to the elevation and
weather.
Example
0 m above sea level: Approx: 101
kPa
3000 m above sea level:Approx: 70
kPa
While the engine is being cranked:
Displays the intake air pressure.
D05 Intake air temperature DisplayDisplays the intake air tempera-
ture.
• Check the temperature in the in-
take manifold.-20–100°C
Cold engine: Displayed tempera-
ture is close to the ambient temper-
ature.
Warm engine: Displayed tempera-
ture is approximately 20 °C higher
than the ambient temperature.
D06 Coolant temperature DisplayDisplays the coolant temperature.
• Check the coolant temperature.-20–150°C
Cold engine: Displayed tempera-
ture is close to the ambient temper-
ature.
Warm engine: Displayed tempera-
ture is the current coolant tempera-
ture.
D08 Lean angle sensor DisplayDisplays the lean angle sensor
output voltage.
Remove the ECU and incline it 45°
or more.0–5.0 V
1.0 V: Upright
4.0 V: Overturned
D30 Ignition coil ActuationCheck that power is supplied to
the ignition coil.
• Check that a spark is generated.
• Illuminates the engine trouble
warning light.Actuates the ignition coil for five
times every second.
The "WARNING" LED on the FI di-
agnostic tool comes on each time
the fuel injector is actuated.

7-13
FUEL INJECTION SYSTEM
TROUBLESHOOTING DETAILS
This section describes the countermeasures per fault code number displayed on the FI diagnostic tool. Check and service
the items or components that are the probable cause of the malfunction following the order given. After the check and ser-
vice of the malfunctioning part have been completed, reset the FI diagnostic tool display according to the "Reinstatement
method".
Fault code No.
Fault code number displayed on the FI diagnostic tool when the engine failed to work normally. Refer to "FAULT CODE
TABLE".
Diagnostic code No.
Diagnostic code number to be used when the diagnostic mode is operated. Refer to "DIAGNOSTIC CODE TABLE".
Fault code No. 12
Symptom No normal signals are received from the crankshaft position sensor.
Fail-safe system Able to start
Able to drive
Diagnostic code No. —
FI diagnostic tool display —
Checking method —
Item Item/components and probable cause Check or maintenance job Checking method
1 Check the connection and locking condition of
the crankshaft position 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.Crank the engine and
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.Crank the engine and
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 crankshaft position
sensor coupler and ECU coupler.
(Gray–Gray)
(Black/Blue–Black/Blue)Crank the engine and
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 gap between the crankshaft po-
sition sensor and the rotor is 0.85 mm.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.Crank the engine and
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.

7-14
FUEL INJECTION SYSTEM
If fault code Nos. 13 and 14 are both displayed, perform the checks and maintenance jobs for fault code No. 13 first.
5 Defective crankshaft position sensor. Sensor malfunction → Replace.
Refer to "CHECKING THE AC
MAGNETO" section.Crank the engine and
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. 13
Symptom Intake air pressure sensor signal is not received properly.
Fail-safe system Able to start
Able to drive
Diagnostic code No. D03
FI diagnostic tool display Intake air pressure
Checking method Crank the engine. (If the display value changes, the performance is OK.)
Item Item/components and probable cause Check or maintenance job Checking method
1 Check the connection and locking condition of
the intake air 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. Fault code No. 12
Symptom No normal signals are received from the crankshaft position sensor.
Fail-safe system Able to start
Able to drive
Diagnostic code No. —
FI diagnostic tool display —
Checking method —
Item Item/components and probable cause Check or maintenance job Checking method

7-15
FUEL INJECTION SYSTEM
3 Continuity of harness Open or short circuit → Replace.
Between the intake air pressure
sensor coupler and ECU coupler.
(Black/Blue–Black/Blue)
(Pink/White–Pink/White)
(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.
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 5.
5 Defective intake air pressure sensor. Execute the diagnostic mode (di-
agnostic code No. D03).
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
Check that the value changes
while the engine is being
cranked.
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. 13
Symptom Intake air pressure sensor signal is not received properly.
Fail-safe system Able to start
Able to drive
Diagnostic code No. D03
FI diagnostic tool display Intake air pressure
Checking method Crank the engine. (If the display value changes, the performance is OK.)
Item Item/components and probable cause Check or maintenance job Checking method

7-16
FUEL INJECTION SYSTEM
If fault code Nos. 13 and 14 are both displayed, perform the checks and maintenance jobs for fault code No. 13 first.
Fault code No. 14
SymptomIntake air pressure sensor system malfunction detected. (clogged hole or disconnected
sensor)
Fail-safe system Able to start
Able to drive
Diagnostic code No. D03
FI diagnostic tool display Intake air pressure
Checking method Crank the engine. (If the display value changes, the performance is OK.)
Item Item/components and probable cause Check or maintenance job Checking method
1 Intake air pressure sensor hose is clogged,
damaged, disconnected, kinked, pinched, or
twisted.Repair or replace. Start the engine and let it
idle for approximately 5
seconds with the throttle
fully closed.
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 intake air pressure sensor. Execute the diagnostic mode (di-
agnostic code No. D03).
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
Display value does not change→
Replace the sensor.

7-17
FUEL INJECTION SYSTEM
Fault code No. 15
Symptom Throttle position sensor signal is not received properly.
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 Check the connection and locking condition of
the throttle position 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 throttle position sensor
coupler and ECU coupler.
(Black/Blue–Black/Blue)
(Yellow–Yellow)
(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.
• 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
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.

7-18
FUEL INJECTION SYSTEM
5 Applied voltage of throttle position sensor lead Measure the output voltage.
Refer to "CHECKING THE
THROTTLE POSITION SEN-
SOR".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. Open circuit
itemApplied voltage
Ground wire
open circuit5 V
Output wire
open circuit0 V
Power supply
wire open circuit0 V
6 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
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 7.
7 Malfunction in ECU. Replace the ECU. Fault code No. 15
Symptom Throttle position sensor signal is not received properly.
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