Yamaha YZ450FF 1SL-28199-11, Owner'S Service Manual

Page: 315 / 358

FUEL INJECTION SYSTEM
8-25
4 Connection of sub wire har-
ness coupler.
Check the locking condition
of the coupler.
Disconnect the coupler, and
check the pins (for bent or
broken terminals and locking
condition of the pins).
Improperly connected

Connect the coupler secure-
ly, or repair/replace the sub-
wire harness.
After starting the engine, idle
this and wait about 5 sec-
onds.
Fault code No. is not dis-
played

Repair is finished.
Fault code No. is displayed

Go to next order.
5 Wire harness continuity. Open or short circuit

Re-
place the wire harness.
Between injector coupler and
ECU coupler.
red/black–red/black
Between injector coupler and
rectifier/regulator coupler
red–red
After starting the engine, idle
this and wait about 5 sec-
onds.
Fault code No. is not dis-
played

Repair is finished.
Fault code No. is displayed

Go to next order.
6 Faulty ECU Replace the ECU.
Fault code 41
Symptom 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.
• 1.0 V (upright)
• 4.0 V (overturned)
Procedure Remove the ECU, and incline it 45° or more.
Or-
der
Probable cause of malfunc-
tion and check
Maintenance job Reinstatement method
1 Faulty ECU Replace the ECU.
Fault code 39
Symptom Injector: open or short circuit detected.