Yamaha YZ450FP 2023 Owner's Service Manual page 322

Fault code No.
Item
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).
3 Wire harness continuity.
4 Mounted condition of intake air
pressure sensor.
Check for looseness or pinch-
ing.
Check the mounted position for
correctness.
5 Defective intake air pressure
sensor.
6 Faulty ECU.
7 Delete the fault code.
13
Intake air pressure sensor: open or short circuit detected.
Improperly connected  Con-
nect the coupler securely, or
repair/replace the wire harness.
Open or short circuit  Replace
the wire harness.
Between intake air pressure
sensor coupler and ECU cou-
pler.
white–white
blue–blue
Between intake air pressure
sensor coupler and joint con-
nector.
black–black
Between joint connector and
ECU coupler.
black/blue–black/blue
Improperly mounted sensor 
Remount or replace the sensor.
Execute the diagnostic mode.
(Code No. 03)
Proper display:
Atmospheric pressure at the
current altitude and weather
conditions is indicated while
engine stopping.
0 m above sea level: About 101
kPa (about 3.63 V)
1000 m above sea level: About
90 kPa (about 3.30 V)
2000 m above sea level: About
80 kPa (about 3.00 V)
3000 m above sea level: About
70 kPa (about 2.70 V)
Abnormal display  Intake air
pressure sensor is defective 
Replace the intake air pressure
sensor.
Replace the ECU.
Confirm that the fault code has
a condition of "Recovered"
using the Yamaha diagnostic
tool, and then delete the fault
code.
8-23
FUEL INJECTION SYSTEM
Start switch to ON (no need to
start the engine), 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.
Start switch to ON (no need to
start the engine), 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.
Start switch to ON (no need to
start the engine), 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.
Start switch to ON (no need to
start the engine), 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 6.
Service is finished.