Yamaha YZ 2023 Series, Owner'S Service Manual

Page: 321 / 378

FUEL INJECTION SYSTEM
8-34
3 Connection of sub wire harness
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).
Improperly connected

Con-
nect the coupler securely, or
repair/replace the sub wire har-
ness.
Start the engine and let it idle for
approximately 5 seconds.
Check the condition of the fault
code using the malfunction
mode of the Yamaha diagnostic
tool.
Condition is “Recovered”

Go
to item 8 and finish the service.
Condition is “Detected”

Go to
item 4.
4 Wire harness continuity. Open or short circuit

Replace
the wire harness.
Between ignition coil coupler
and ECU coupler.
orange–orange
red–red/blue
Start the engine and let it idle for
approximately 5 seconds.
Check the condition of the fault
code using the malfunction
mode of the Yamaha diagnostic
tool.
Condition is “Recovered”

Go
to item 8 and finish the service.
Condition is “Detected”

Go to
item 5.
5 Mounted condition of ignition
coil.
Check for looseness or pinch-
ing.
Check the mounted condition
for correctness.
Improperly mounted sensor

Remount or replace the ignition
coil.
Start the engine and let it idle for
approximately 5 seconds.
Check the condition of the fault
code using the malfunction
mode of the Yamaha diagnostic
tool.
Condition is “Recovered”

Go
to item 8 and finish the service.
Condition is “Detected”

Go to
item 6.
6 Defective ignition coil. (test the
primary coils for continuity)
Check the primary resistance of
the ignition coil.
Refer to “CHECKING THE
IGNITION COIL” on page 8-54.
Start the engine and let it idle for
approximately 5 seconds.
Check the condition of the fault
code using the malfunction
mode of the Yamaha diagnostic
tool.
Condition is “Recovered”

Go
to item 8 and finish the service.
Condition is “Detected”

Go to
item 7.
7 Faulty ECU. Execute the diagnostic mode.
(Code No. 30)
No spark

Replace the ECU.
Service is finished.
8 Delete the fault code. Confirm that the fault code has
a condition of “Recovered”
using the Yamaha diagnostic
tool, and then delete the fault
code.
Fault code No. 33
Item
Ignition coil: open or short circuit detected in the primary lead of
the ignition coil.