Yamaha YZ 2018 Series Owner's Service Manual page 332

Fault code No.
Item
1 Connection of throttle posi-
tion sensor coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).
2 Connection of wire harness
ECU coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).
3 Wire harness continuity.
4 Installed condition of throttle
position sensor.
Check for looseness or
pinching.
5 Applied voltage of throttle po-
sition sensor lead.
15
Throttle position sensor: open or short circuit detected.
Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.
Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.
Open or short circuit  Re-
place the wire harness.
Between throttle position
sensor coupler and ECU cou-
pler.
black/blue–black/blue
yellow–yellow
blue–blue
Improperly installed sensor
 Reinstall or replace the
sensor.
Refer to "ADJUSTING THE
THROTTLE POSITION SEN-
SOR" on page 7-10.
Check the applied voltage.
(black/blue–blue)
Location of discon-
nected lead
Disconnected
ground lead
Disconnected out-
put lead
Disconnected
power supply lead
8-33
FUEL INJECTION SYSTEM
Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 2.
Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 3.
Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 4.
Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 5.
Push the start switch.
Fault code number is not dis-
played  Service is finished.
Output
Fault code number is dis-
voltage
played  Go to item 6.
5V
0V
0V