Yamaha YZ450F Owner's Service Manual page 215

Fault code No.
Symptom
Fail-safe system
Diagnostic code No.
FI diagnostic tool display
Checking method
Item Item/components and probable cause
4 Continuity of harness
5 Malfunction in ECU.
Fault code No.
Symptom
Fail-safe system
Diagnostic code No.
FI diagnostic tool display
Checking method
Item Item/components and probable cause
1 Malfunction in ECU.
39
Injection system circuit signal is not received properly.
Unable to start
Unable to drive
D36
Actuates the injector for five times every second.
The "WARNING" LED on the FI diagnostic tool comes on each time the fuel injector is ac-
tuated.
Check the operating sound of the injector five times.
41
Lean angle sensor malfunction. (the sensor is built into the ECU)
Unable to start
Unable to drive
D08
Lean angle sensor
• 1.0 V (Upright)
• 4.0 V (Overturned)
Remove the ECU and incline it 45 ° or more.
FUEL INJECTION SYSTEM
Check or maintenance job
Open or short circuit → Replace.
Between injector coupler and ECU
coupler.
(Red–Red)
(Red/Black–Red/Black)
Replace the ECU.
Check or maintenance job
Replace the ECU.
7-29
Checking method
Start the engine and let it
idle for approximately 5
seconds.
After completing the above
operation, check whether a
fault code number is dis-
played.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item
5.
Checking method