Yamaha YZ 2023 Series, Owner'S Service Manual

Page: 323 / 378

FUEL INJECTION SYSTEM
8-36
Fault code No. 41
Fault code No. 43
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
Unable 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 main relay
and CCU.
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 main relay, and push the start switch.
Item
Probable cause of malfunc-
tion and check
Maintenance job
Confirmation of service com-
pletion
1 Connection of main relay cou-
pler.
Check the locking condition of
the coupler.
Disconnect the coupler, and
check the pins (bent or broken
terminals and locking condition
of the pins).
Improperly connected

Con-
nect the coupler securely, or
repair/replace the wire harness.
Press the start switch and the
engine stop switch alternately to
switch the power supply (= main
relay) from “ON

OFF

ON”.
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 2.
Fault code No. 39
Item Injector: open or short circuit detected.