2014 YAMAHA YZ450F check engine

FUEL INJECTION SYSTEM
8-15
TIP
If fault code Nos. 13 and 14 are both displayed, perform checkup and repair jobs for fault code No.
13 first.
Fault code13
SymptomIntake air pressure sensor: open or short circuit detected.
Fail-safe systemAble to start engine
Able to drive vehicle
Diagnostic code No.03
Diagnostic tool displayDisplays the intake air pressure.
ProcedureThe atmospheric pressure is displayed on the Yamaha diagnostic
tool.
Or-
der
Probable cause of malfunc-
tion and checkMaintenance jobReinstatement method
1Connection of intake air pres-
sure sensor 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 wire
harness.
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.
2Connection of wire harness
ECU 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 wire
harness.
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.
3Connection 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.
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.
4Wire harness continuity.Open or short circuit  Re-
place the wire harness.
Between intake air pressure
sensor coupler and ECU cou
-
pler.
pink/black–pink/black
blue–blue
black/blue–black/blue
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.
5Mounted condition of intake
air pressure sensor.
Check for looseness or
pinching.
Check the mounted position
for correctness.
Improperly mounted sensor
 Remount or replace the
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.

FUEL INJECTION SYSTEM
8-16
TIP
If fault code Nos. 13 and 14 are both displayed, perform checkup and repair jobs for fault code No.
13 first.
6Defective intake air pressure
sensor.Execute the diagnostic mode.
(Code No.03)
Atmospheric pressure at the
current altitude and weather
conditions is indicated.
0 m above sea level: About
101 kPa
1000 m above sea level:
About 90 kPa
2000 m above sea level:
About 80 kPa
3000 m above sea level:
About 70 kPa
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.
7Faulty ECUReplace the ECU.
Fault code14
SymptomIntake air pressure sensor: hose system malfunction (clogged
or detached hose)
Fail-safe systemAble to start engine
Able to drive vehicle
Diagnostic code No.03
Diagnostic tool displayDisplays the intake air pressure.
ProcedureThe atmospheric pressure is displayed on the Yamaha diagnostic
tool.
Or-
der
Probable cause of malfunc-
tion and checkMaintenance jobReinstatement method
1The intake air pressure sen-
sor hose is damaged, discon-
nected, clogged, twisted or
bent.
Repair or replace the sensor
hose.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.
Fault code 13
Symptom Intake air pressure sensor: open or short circuit detected.

FUEL INJECTION SYSTEM
8-17
2Defective intake air pressure
sensor.Execute the diagnostic mode.
(Code No. 03)
Atmospheric pressure at the
current altitude and weather
conditions is indicated.
0 m above sea level: About
101 kPa
1000 m above sea level:
About 90 kPa
2000 m above sea level:
About 80 kPa
3000 m above sea level:
About 70 kPa
Fault code15
SymptomThrottle position sensor: open or short circuit detected.
Fail-safe systemAble to start engine
Able to drive vehicle
Diagnostic code No.01
Diagnostic tool displayDisplays the throttle angle.
• 11–14 (throttle in fully closed position)
• 109–116 (throttle in fully opened position)
ProcedureCheck with throttle valves fully closed.
Check with throttle valves fully opened.
Or-
der
Probable cause of malfunc-
tion and checkMaintenance jobReinstatement method
1Connection of throttle posi-
tion sensor 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 wire
harness.
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.
2Connection of wire harness
ECU 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 wire
harness.
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.
Fault code 14
SymptomIntake air pressure sensor: hose system malfunction (clogged
or detached hose)

FUEL INJECTION SYSTEM
8-19
Fault code16
SymptomThrottle position sensor: stuck throttle position sensor is de-
tected.
Fail-safe systemAble to start engine
Able to drive vehicle
Diagnostic code No.01
Diagnostic tool displayDisplays the throttle angle.
• 11–14 (throttle in fully closed position)
• 109–116 (throttle in fully opened position)
ProcedureCheck with throttle valves fully closed.
Check with throttle valves fully opened.
Or-
der
Probable cause of malfunc-
tion and checkMaintenance jobReinstatement method
1Mounted condition of throttle
position sensor.
Check for looseness or
pinching.
Check the mounted condition
for correctness.
Improperly mounted sensor
 Remount or replace the
sensor.
Refer to “ADJUSTING THE
THROTTLE POSITION SEN-
SOR” on page 7-9.
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.
2Defective throttle position
sensor.Execute the diagnostic mode.
(Code No. d:01)
When the throttle is fully
closed, 11–14 displays.
When the throttle is fully
opened, 109–116 displays.
Incorrect display range 
Replace the throttle position
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.
3Faulty ECUReplace the ECU.

FUEL INJECTION SYSTEM
8-20
TIP
Make sure that the machine is completely cold before checking the coolant temperature sensor.
Fault code21
SymptomCoolant temperature sensor: open or short circuit detected.
Fail-safe systemAble to start engine
Able to drive vehicle
Diagnostic code No.06
Diagnostic tool displayDisplays the coolant temperature.
ProcedureCompare the actually measured coolant temperature with the
Yamaha diagnostic tool display value.
Or-
der
Probable cause of malfunc-
tion and checkMaintenance jobReinstatement method
1Connection of coolant tem-
perature sensor 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 wire
harness.
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.
2Connection of wire harness
ECU 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 wire
harness.
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.
3Wire harness continuity.Open or short circuit  Re-
place the wire harness.
Between coolant temperature
sensor coupler and ECU cou
-
pler.
green/white–green/white
black/blue–black/blue
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.
4Mounted condition of coolant
temperature sensor.
Check for looseness or
pinching.
Check the mounted condition
for correctness.
Improperly mounted sensor
 Remount or replace the
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.
5Defective coolant tempera-
ture sensor.
Execute the diagnostic mode.
(Code No. 06)
When the machine is cold,
displayed temperature is
close to the ambient temper
-
ature.
Improper display  Replace
the coolant temperature sen
-
sor.
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.
6Faulty ECUReplace the ECU.

FUEL INJECTION SYSTEM
8-21
TIP
Make sure that the machine is completely cold before checking the intake air temperature sensor.
Fault code22
SymptomIntake air temperature sensor: open or short circuit detected.
Fail-safe systemAble to start engine
Able to drive vehicle
Diagnostic code No.05
Diagnostic tool displayDisplays the intake air temperature.
ProcedureCompare the actually measured intake air temperature with the
Yamaha diagnostic tool display value.
Or-
der
Probable cause of malfunc-
tion and checkMaintenance jobReinstatement method
1Connection of intake air tem-
perature sensor 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 wire
harness.
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.
2Connection of wire harness
ECU 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 wire
harness.
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.
3Wire harness continuity.Open or short circuit  Re-
place the wire harness.
Between intake air tempera-
ture sensor coupler and ECU
coupler.
brown/white–brown/white
black/blue–black/blue
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.
4Mounted condition of intake
air temperature sensor.
Check for looseness or
pinching.
Check the mounted condition
for correctness.
Improperly mounted sensor
 Remount or replace the
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.
5Defective 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.
6Faulty ECUReplace the ECU.

FUEL INJECTION SYSTEM
8-22
Fault code30
SymptomThe vehicle has overturned.
Fail-safe systemAble to start engine
Unable to drive vehicle
Diagnostic code No.08
Diagnostic tool displayDisplays the lean angle sensor output voltage.
• 1.0 V (upright)
• 4.0 V (overturned)
ProcedureRemove the ECU, and incline it 45° or more.
Or-
der
Probable cause of malfunc-
tion and checkMaintenance jobReinstatement method
1The 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.
2Mounted 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.
3Faulty ECUExecute 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.

FUEL INJECTION SYSTEM
8-23
Fault code33
SymptomIgnition coil: open or short circuit detected in the primary lead
of the ignition coil.
Fail-safe systemUnable to start engine
Unable to drive vehicle
Diagnostic code No.30
ActuationActuates the ignition coil five times at one-second intervals.
“WARNING” on the Yamaha diagnostic tool blinks five times when-
ever the ignition coil is actuated.
ProcedureCheck that a spark is generated five times.
• Connect an ignition checker.
Or-
der
Probable cause of malfunc-
tion and checkMaintenance jobReinstatement method
1Connection of ignition coil
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 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.
2Connection of wire harness
ECU 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 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.
3Wire harness continuity.Open or short circuit  Re-
place the wire harness.
Between ignition coil coupler
and ECU coupler.
orange–orange
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.
4Mounted condition of ignition
coil.
Check for looseness or
pinching.
Check the mounted condition
for correctness.
Improperly mounted ignition
coil  Remount or replace
the ignition coil.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.
5Defective ignition coil (test
the primary coils for continu
-
ity).
Check the primary resistance
of the ignition coil.
“CHECKING THE IGNITION
COIL” on page 8-41.
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.