Yamaha YZ 2015 Series Owner's Service Manual page 342

Fault code No.
Item
3 Connection of sub wire har-
ness 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).
4 Wire harness continuity.
5 Installed condition of ignition
coil.
Check for looseness or
pinching.
6 Defective ignition coil. (test
the primary coils for continu-
ity)
7 Malfunction in ECU.
33
Ignition coil: open or short circuit detected in the primary lead
of the ignition coil.
Improperly connected 
Connect the coupler securely
or repair/replace the sub wire
harness.
Open or short circuit  Re-
place the wire harness.
Between ignition coil coupler
and ECU coupler.
orange–orange
Improperly installed sensor
 Reinstall or replace the
sensor.
Check the ignition coil.
Replace if defective.
Refer to "CHECKING THE
IGNITION COIL" on page 8-
62.
Execute the diagnostic mode
(diagnostic code No. 30).
No spark  Replace the
ECU.
8-36
FUEL INJECTION SYSTEM
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 4.
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 5.
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 6.
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 7.