Yamaha YZ 2020 Series Owner's Service Manual page 312

Fault code No.
Item
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.
Fault code No. 14
TIP
• If fault code numbers 13 and 14 are both displayed, perform checkup and repair jobs for fault code
number 13 first.
• Before troubleshooting, disconnect the starter motor lead from the starter relay.
Fault code No.
Item
Fail-safe system
Diagnostic code No.
Diagnostic tool display
Procedure
Probable cause of malfunc-
Item
tion and check
13
Intake air pressure sensor: open or short circuit detected.
Improperly mounted sensor 
Remount or replace the sensor.
Execute the diagnostic mode.
(Code No. 03)
Atmospheric pressure at the
current altitude and weather
conditions is indicated.
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.
14
Intake air pressure sensor: hose system malfunction (clogged or
detached hose).
Able to start engine
Able to drive vehicle
03
Displays the intake air pressure.
The atmospheric pressure is displayed on the Yamaha diagnostic tool.
Maintenance job
8-25
FUEL INJECTION SYSTEM
Start switch to ON (main relay
ON), and then check the condi-
tion 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 (main relay
ON), and then check the condi-
tion 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.
Confirmation of service com-
pletion