Yamaha YZ450F Owner's Service Manual page 220

Fault code No.
Symptom
Fail-safe system
Diagnostic code No.
FI diagnostic tool display
Checking method
Item Item/components and probable cause
1 Check the connection and locking condition of
the FI diagnostic tool coupler.
Disconnect the coupler and check the pins.
(bent or broken terminals and locking condition
of the pins)
2 Check the connection and locking condition of
the wire harness ECU coupler.
Disconnect the coupler and check the pins.
(bent or broken terminals and locking condition
of the pins)
3 Continuity of harness
4 FI diagnostic tool malfunction
5 Malfunction in ECU.
Er-4
Registered data cannot be received from the FI diagnostic tool.
Able to start
Able to drive
—
—
—
FUEL INJECTION SYSTEM
Check or maintenance job
Poor connection → Properly con-
nect, repair, or replace.
Poor connection → Properly con-
nect, repair, or replace.
Open or short circuit → Replace.
Between FI diagnostic tool coupler
and ECU coupler.
(Light green–Light green)
Replace the FI diagnostic tool.
Replace the ECU.
7-34
Checking method
Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 2.
Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 3.
Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 4.
Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 5.