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

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FUEL INJECTION SYSTEM
8-22
5 Defective intake air tempera-
ture sensor.
Execute the diagnostic mode.
(Code No. 05)
When the machine is cold,
displayed temperature is
close to the ambient temper-
ature.
Improper display

Replace
the intake air temperature
sensor.
Turn “ON” the switch on the
FI diagnostic tool sub-lead.
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 30
Symptom The vehicle has overturned.
Fail-safe system Able to start engine
Unable 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 The vehicle has overturned. Raise the vehicle upright. Turn “ON” the switch on the
FI diagnostic tool sub-lead.
Fault code No. is not dis-
played

Repair is finished.
Fault code No. is displayed

Go to next order.
2 Mounted condition of ECU.
Check for looseness or
pinching.
Check the mounted condition
for correctness.
Improperly mounted ECU

Remount the ECU.
Turn “ON” the switch on the
FI diagnostic tool sub-lead.
Fault code No. is not dis-
played

Repair is finished.
Fault code No. is displayed

Go to next order.
3 Faulty ECU Execute the diagnostic mode.
(Code No. 08)
When the vehicle is upright:
1.0 V
When the vehicle is over-
turned: 4.0 V
Improper display

Replace
the ECU.
Fault code 22
Symptom Intake air temperature sensor: open or short circuit detected.