Yamaha WR250F Owner's Service Manual page 383

Fault code No.
Item
Fail-safe system
Diagnostic code No.
Diagnostic tool display
Procedure
Probable cause of malfunc-
Item
tion and check
1 Connection of main relay
coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).
2 Connection of wire harness
ECU coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).
3 Wire harness continuity.
4 Defective main relay.
5 Defective main relay.
6 Malfunction in ECU.
43
Fuel system voltage: incorrect voltage supplied to the fuel in-
jector and fuel pump.
Able to start engine
Able to drive vehicle
09
Fuel system voltage
Approximately 12.0 (V)
Disconnect the main relay, and push the start switch or push down
the kickstarter lever.
Maintenance job
Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.
Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.
Open or short circuit  Re-
place 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
No operating sound  Re-
place the main relay.
Execute the diagnostic mode.
(Code No. 09)
Fuel system voltage is below
3 V  Replace the main re-
lay.
Replace the ECU.
9-49
FUEL INJECTION SYSTEM
Confirmation of service
completion
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 dis-
played  Go to item 2.
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 dis-
played  Go to item 3.
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 dis-
played  Go to item 4.
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 dis-
played  Go to item 5.
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 dis-
played  Go to item 6.