Yamaha WR450F 2021 Owner's Service Manual page 342

Fault code No.
Item
3 Faulty ECU.
4 Delete the fault code.
Fault code No. 33
Fault code No.
Item
Fail-safe system
Diagnostic code No.
Actuation
Procedure
Probable cause of malfunc-
Item
tion and check
1 Connection of ignition coil cou-
pler.
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).
2 Connection of wire harness
ECU 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).
30
The vehicle has overturned.
Execute the diagnostic mode.
(Code No. 08)
When the vehicle is upright:
0.4–1.4 (V)
When the vehicle is overturned:
3.7–4.4 (V)
Improper display  Replace the
ECU.
Confirm that the fault code has
a condition of "Recovered"
using the Yamaha diagnostic
tool, and then delete the fault
code.
33
Ignition coil: open or short circuit detected in the primary lead of
the ignition coil.
Unable to start engine
Unable to drive vehicle
30
Actuates the ignition coil five times at one-second intervals.
"WARNING" on the Yamaha diagnostic tool blinks five times when the
ignition coil is actuated.
Check that a spark is generated five times.
• Connect an ignition checker.
Maintenance job
Improperly connected  Con-
nect the coupler securely, or
repair/replace the wire harness.
Improperly connected  Con-
nect the coupler securely, or
repair/replace the wire harness.
8-43
FUEL INJECTION SYSTEM
Service is finished.
Confirmation of service com-
pletion
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 2.
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 3.