Yamaha YZ 2019 Series, Owner'S Service Manual

Page: 336 / 398

FUEL INJECTION SYSTEM
8-37
Fault code No. 43
Fault code No. 43
Item
Fuel system voltage: incorrect voltage supplied to the fuel injector
and fuel pump.
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.
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 displayed

Go to item 2.
2 Connection of wire harness
ECU coupler.
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.
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 displayed

Go to item 3.
3 Wire harness continuity. Open or short circuit

Replace
the wire harness.
Between battery terminal and
ECU coupler.
red–red
red–red/white
Between main relay coupler and
ECU coupler.
brown–brown
blue/red–blue/red
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 displayed

Go to item 4.
4 Defective main relay. No operating sound

Replace
the main relay.
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 displayed

Go to item 5.
5 Defective main relay. Execute the diagnostic mode.
(Code No. 09)
Fuel system voltage is below 3
V

Replace the main relay.
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 displayed

Go to item 6.
6 Malfunction in ECU. Replace the ECU.