2014 YAMAHA YZ450F ignition

IGNITION SYSTEM
8-5
8. Check the ignition system wire har-
ness.
Refer to “CIRCUIT DIAGRAM” on
page 8-2.
NG 
Repair or replace the wire harness.
OK 
Replace the ECU.

FUEL INJECTION SYSTEM
8-12
YAMAHA DIAGNOSTIC TOOL
This model uses the Yamaha diagnostic tool to identify malfunctions.
For information about using the Yamaha diagnostic tool, refer to the operation manual that is included
with the tool.
FEATURES OF THE YAMAHA DIAGNOSTIC TOOL
A diagnosis can be made more quickly than traditional methods with the Yamaha diagnostic tool.
Using this software, ECU and sensor data, as well as fault diagnosis, vehicle maintenance, and any
necessary information can be recorded and displayed on your computer screen through a USB
adapter connected to the computer interface with a communication cable connected to the vehicle's
ECU.
Data obtained in various functions can be saved as vehicle history, and can be accumulated.
FUNCTIONS OF THE YAMAHA DIAGNOSTIC TOOL
However, the diagnostic tool cannot be used to freely change the basic vehicle functions, such as
adjusting the ignition timing.
CONNECTING THE YAMAHA DIAGNOSTIC TOOL
1. Remove the coupler for connecting setting tool.
Yamaha diagnostic tool
90890-03215
Fault diagnosis modeFault codes recorded on the ECU are read, and the con-
tents are displayed.
Function diagnostic modeCheck the operation of the output value of each sensor
and actuator.
Inspection modeDetermine whether each sensor or actuator is functioning
properly.
CO adjustment modeAdjust the concentration of CO admissions during idling.
Monitoring modeDisplays a graph of sensor output values for actual oper-
ating conditions.
Logging modeRecords and saves the sensor output value in actual driv-
ing conditions.
View logDisplays the logging data.
ECU rewriteIf necessary, the ECU is rewritten using the ECU rewrite
data provided by Yamaha. Ignition timing adjustment, etc.
cannot be changed from the vehicle's original state.

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.

FUEL INJECTION SYSTEM
8-24
TIP
Disconnect the fuel pump coupler when this diagnostic tool is used.
6Faulty ECUExecute the diagnostic mode.
(Code No. 30)
No spark  Replace the
ECU.
Fault code39
SymptomInjector: open or short circuit detected.
Fail-safe systemUnable to start engine
Unable to drive vehicle
Diagnostic code No.36
ActuationActuates injector five times at one-second intervals.
“WARNING” on the Yamaha diagnostic tool blinks five times when
the injector is actuated.
ProcedureCheck that injector is actuated five times by listening for the oper-
ating sound.
Or-
der
Probable cause of malfunc-
tion and checkMaintenance jobReinstatement method
1Connection of injector cou-
pler.
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.
2Defective injector.Check the injector.
“CHECKING THE FUEL IN-
JECTOR” on page 8-47.
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.
3Connection 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.
Fault code 33
SymptomIgnition coil: open or short circuit detected in the primary lead
of the ignition coil.

FUEL INJECTION SYSTEM
8-26
Fault code44
SymptomEEPROM fault code No.: an error is detected while reading or
writing on EEPROM.
Fail-safe systemAble/Unable to start engine
Able/Unable to drive vehicle
Diagnostic code No.60
Diagnostic tool displayDisplays the location of the abnormal portion of the EEPROM data.
• 00: No fault
• 01: CO adjustment valve
• 07: Power Tuner injection correction setting 0–8, or Power Tuner
ignition timing correction setting 0–8
Procedure—
Or-
der
Probable cause of malfunc-
tion and checkMaintenance jobReinstatement method
1Identification of malfunction-
ing point.
Execute the diagnostic mode.
(Code No. 60)
00: Perform a checkup in or-
der 4.
01: Perform a checkup in or-
der 2.
07: Perform a checkup in or-
der 3.
2“01” is indicated in Diagnostic
mode (Code No. 60). EEP-
ROM data error for adjust
-
ment of CO concentration.
Change the CO concentra-
tion, and rewrite in EEPROM.
After this adjustment, turn
OFF the switch on the FI di
-
agnostic tool sub-lead, and
turn it ON again.
Memory not recovered  Re-
place 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 number is dis-
played  Repeat the proce-
dure in order 1. If the same
number is indicated, perform
the procedure in order 3.
3“07” is indicated in Diagnostic
mode (Code No. 60). EE
-
PROM data error for setting
tool adjustment values for
fuel injection amount or igni
-
tion timing.
Erase the setting map in the
diagnostic mode.
(Code No. 65)
Turn “ON” the switch on the
FI diagnostic tool sub-lead.
Fault code No. is not dis-
played  Repair is finished.
Fault code number is dis-
played  Repeat the proce-
dure in order 1. If the same
number is indicated, perform
the procedure in order 4.
4Faulty ECUReplace the ECU.

ELECTRICAL COMPONENTS
8-37
EAS1SL1334
1. Rectifier/regulator
2. Intake air pressure sensor
3. Throttle position sensor
4. Injector
5. Intake air temperature sensor
6. ECU
7. Ignition coil
8. Condenser
9. Neutral switch
10.Coolant temperature sensor

ELECTRICAL COMPONENTS
8-41
EAS1SL1335CHECKING THE IGNITION SPARK GAP
1. Check:
• Ignition spark gap
Out of specification  Perform the ignition
system troubleshooting.
Refer to “TROUBLESHOOTING” on page 8-
4.
TIP
If the ignition spark gap is within specification,
the ignition system circuit is operating normally.
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a. Remove the spark plug cap from the spark
plug.
b. Connect the ignition checker “1.”
c. Crank the engine, and measure the ignition
spark gap “a”.
d. Crank the engine, and gradually increase
the spark gap until a misfire occurs.
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EAS1SL1336CHECKING THE SPARK PLUG CAP
1. Remove:
• Spark plug cap
(from the spark plug lead)
2. Check:
• Spark plug cap resistance
Out of specification  Replace.
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a. Connect the pocket tester ( 1k) to the
spark plug cap.
b. Measure the spark plug cap resistance.
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EAS1SL1337CHECKING THE IGNITION COIL
1. Disconnect:
• Ignition coil terminal
(from the sub wire harness)
• Spark plug cap
(from the ignition coil)
2. Check:
• Primary coil resistance
Out of specification  Replace.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Connect the pocket tester ( 1) to the igni-
tion coil.
Minimum ignition spark gap
6.0 mm (0.24 in)
Ignition checker
90890-06754
Oppama pet-4000 spark checker
YM-34487
2. Spark plug cap
Spark plug cap resistance
10 k
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Primary coil resistance
2.16–2.64 
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe 
Ignition coil terminal 1 “1”
• Negative tester probe 
Ignition coil terminal 2 “2”

ELECTRICAL COMPONENTS
8-42
b. Measure the primary coil resistance.
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3. Check:
• Secondary coil resistance
Out of specification  Replace.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Connect the pocket tester ( 1k) to the ig-
nition coil.
b. Measure the secondary coil resistance.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS1SL1338
CHECKING THE CRANKSHAFT POSITION
SENSOR
1. Disconnect:
• Crankshaft position sensor coupler
(from the wire harness)
2. Check:
• Crankshaft position sensor resistance
Out of specification  Replace.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Connect the pocket tester ( 100) to the
crankshaft position sensor coupler.
b. Measure the crankshaft position sensor re-
sistance.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS1SL1339
Secondary coil resistance
8.64–12.96 k
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe 
Ignition coil terminal 1 “1”
• Negative tester probe 
Spark plug lead “2”
Crankshaft position sensor resis-
tance
228–342 
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe 
Gray “1”
• Negative tester probe 
Black “2”
12
Gy B