Yamaha YZ450F(D) Owner's Service Manual page 199

Fault code No.
Symptom
Fail-safe system
Diagnostic code No.
FI diagnostic tool display
Checking method
Item Item/components and probable cause
3 Continuity of harness
4 Installed condition of sensor.
Make sure that the installation position is cor-
rect.
5 Defective intake air pressure sensor.
6 Malfunction in ECU.
13
Intake air pressure sensor signal is not received properly.
Able to start
Able to drive
D03
Intake air pressure
Crank the engine. (If the display value changes, the performance is OK.)
FUEL INJECTION SYSTEM
Check or maintenance job
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)
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.
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.
Replace the ECU.
7-15
Checking method
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.
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.
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.