Yamaha YZ 2018 Series, Owner'S Service Manual

Page: 331 / 402

FUEL INJECTION SYSTEM
8-32
TIP
Before troubleshooting, disconnect the starter motor lead from the starter relay.
1 The intake air pressure sen-
sor hose is damaged, discon-
nected, clogged, twisted or
bent. Repair or replace the sensor
hose. Start the engine and let it idle
for approximately 5 seconds.
Fault code number is not dis-
played

Service is finished.
Fault code number is dis-
played

Go to item 2.
2 Defective intake air pressure
sensor. Execute the diagnostic mode.
(Code No. 03)
When engine is stopped:
Atmospheric pressure at the
current altitude and weather
conditions is indicated.
At 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
When engine is cranking:
Make sure that the indication
value changes.
The value does not change
when engine is cranking.

Check the intake air pressure
sensor.
Replace if defective.
Refer to “CHECKING THE
INTAKE AIR PRESSURE
SENSOR” on page 8-71.
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 Throttle position sensor signal
• 11–14 (fully closed position)
• 109–116 (fully open position)
Procedure • Check with throttle valve fully closed.
• Check with throttle valve fully open.
Item
Probable cause of malfunc-
tion and check
Maintenance job
Confirmation of service
completion
Fault code No. 14
Item
Intake air pressure sensor: hose system malfunction (clogged
or detached hose).