Yamaha YZ450FP 2023, Owner'S Service Manual

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FUEL INJECTION SYSTEM
8-34
Fault code No. 41
Fault code No. 43
4 Wire harness continuity. Open or short circuit

Replace
the wire harness.
Between injector coupler and
ECU coupler.
red/black–red/black
Between injector coupler and
joint connector.
red–red
Between joint connector and
starter relay.
red/yellow–red/yellow
Between starter relay and bat-
tery terminal.
red–red
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 6 and finish the service.
Condition is “Detected”

Go to
item 5.
5 Faulty ECU. Replace the ECU. Service is finished.
6 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. 41
Item ECU: built-in lean angle sensor malfunction.
Fail-safe system
Able to start engine
Able to drive vehicle
Diagnostic code No.
08
Diagnostic tool display
Displays the lean angle sensor output voltage.
•
0.4–1.4 (V) (upright)
•
3.7–4.4 (V) (overturned)
Procedure
Remove the ECU, and incline it 45

or more.
Item
Probable cause of malfunc-
tion and check
Maintenance job
Confirmation of service com-
pletion
1 Faulty ECU. Replace the ECU. Service is finished.
Fault code No. 43
Item
Fuel system voltage: incorrect voltage supplied to the CCU, and
incorrect recognition voltage of the motorcycle.
Fail-safe system
Able to start engine
Able to drive vehicle
Diagnostic code No.
09
Diagnostic tool display
Fuel system voltage
Approximately 12.0 (V)
Procedure
Disconnect the starter relay, and push the start switch.
Item
Probable cause of malfunc-
tion and check
Maintenance job
Confirmation of service com-
pletion
Fault code No. 39
Item Injector: open or short circuit detected.