Yamaha YZ450FP 2023, Owner'S Service Manual

Page: 320 / 388

FUEL INJECTION SYSTEM
8-21
Fault code No. 12
7 Delete the fault code. Confirm that the fault code has
a condition of “Recovered”
using the Yamaha diagnostic
tool, and then delete the fault
code.
Fault code No. 12
Item
Crankshaft position sensor: no normal signals are received from
the crankshaft position sensor.
Fail-safe system
Unable to start engine
Unable to drive vehicle
Diagnostic code No.
—
Diagnostic tool display
—
Procedure
—
Item
Probable cause of malfunc-
tion and check
Maintenance job
Confirmation of service com-
pletion
1 Connection of crankshaft posi-
tion sensor coupler.
Check the locking condition of
the coupler.
Disconnect the coupler, and
check the pins (for bent or bro-
ken terminals and locking condi-
tion of the pins).
Improperly connected

Con-
nect the coupler securely, or
repair/replace the wire harness.
Crank the engine 2 seconds or
more, and then check the condi-
tion of the fault code using the
malfunction mode of the
Yamaha diagnostic tool.
Condition is “Recovered”

Go
to item 7 and finish the service.
Condition is “Detected”

Go to
item 2.
2 Connection of wire harness
ECU coupler.
Check the locking condition of
the coupler.
Disconnect the coupler, and
check the pins (for bent or bro-
ken terminals and locking condi-
tion of the pins).
Improperly connected

Con-
nect the coupler securely, or
repair/replace the wire harness.
Crank the engine 2 seconds or
more, and then check the condi-
tion of the fault code using the
malfunction mode of the
Yamaha diagnostic tool.
Condition is “Recovered”

Go
to item 7 and finish the service.
Condition is “Detected”

Go to
item 3.
3 Wire harness continuity. Open or short circuit

Replace
the wire harness.
Between crankshaft position
sensor coupler and ECU cou-
pler.
gray–gray
Between crankshaft position
sensor coupler and joint con-
nector.
black/blue–black/blue
Between joint connector and
ECU coupler.
black/blue–black/blue
Crank the engine 2 seconds or
more, and then check the condi-
tion of the fault code using the
malfunction mode of the
Yamaha diagnostic tool.
Condition is “Recovered”

Go
to item 7 and finish the service.
Condition is “Detected”

Go to
item 4.
Fault code No. 8
Item Gear position switch: open or short circuit detected.