2011 YAMAHA YZ450F ignition

7-2
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
WIRING DIAGRAM
1. Crankshaft position sensor
2. AC magneto
3. Rectifier/regulator
4. Condenser
5. Fuel pump
6. Engine stop switch
7. ECU
8. Ignition coil
9. Spark plug
10. Fuel injector
11. Intake air temperature sensor
12. Intake air pressure sensor
13. Throttle position sensor
14. Atmospheric pressure sensor
15. Coolant temperature sensor
16. Coupler for connecting optional part COLOR CODE
BBlack
Br Brown
Gy Gray
LBlue
Lg Light green
O Orange
PPink
RRed
WWhite
YYellow
B/L Black/Blue
B/R Black/Red
B/W Black/White
B/Y Black/Yellow
Br/W Brown/White
P/W Pink/White
R/B Red/Black
R/W Red/White
STOPON
Gy
Gy
B
B
/L
W1
W2
W2 O
R /B
R RR
R
R
R R
Lg
Lg Lg L
P
/W
P YB
/RB
B B
B
B BB
BB/W
B /W
B/W Br
/WGy
B /L
W1 W1
W2 W2 B
/Y
B /Y Br
B /R
R /W
OO
R /B
RR
R
L
P/W
P YL
L
LY
Br /WB /L
B /L
B/L
B
B/L
B/L
Br
W1
Br
/W
W2
R
R O
B/L
L
Y
B /L
Br
R
P
Gy
Gy
B /R
B
/R
R/WB /Y
B
/L
W1
W2
W1 R
R R
B
B
/Y
Lg Lg
O
R /B
R/B
Br /W
P /W P
/W
L L
Y
B /L B
/L
B/L
Br
B
B /W
B
/W
B
B
B L
B
/L
P

7-3
IGNITION SYSTEM
IGNITION SYSTEM
INSPECTION STEPS
Use the following steps for checking the possibility of the malfunctioning engine being attributable to ignition system failure
and for checking the spark plug which will not spark.
*marked: Only when the ignition checker is used.
• Remove the following parts before inspection.
1. Seat
2. Fuel tank
• Use the following special tools in this inspection.
Spark gap testSpark→• *Clean or replace spark plug.
• Check the connection of the spark plug cap to the
spark plug.
No spark↓
Check entire ignition system for connection.
(couplers, leads and ignition coil)No good→
Repair or replace.
OK↓
Check engine stop switch. No good→Replace.
OK↓
Check ignition coil. (primary coil and secondary
coil)No good→
Replace.
OK↓
Check AC magneto. (crankshaft position sensor
and stator coil)No good→
Replace.
OK↓
Replace ECU.
Dynamic spark tester:
YM-34487
Ignition checker:
90890-06754
Pocket tester:
YU-03112-C/90890-03112

7-4
IGNITION SYSTEM
SPARK GAP TEST
1. Disconnect the spark plug cap
from spark plug.
2. Connect the dynamic spark tester
"1" (ignition checker "2") as
shown.
• Spark plug cap "3"
• Spark plug "4"
A. For USA and CDN
B. Except for USA and CDN
3. Kick the kickstarter crank.
4. Check the ignition spark gap.
5. Start engine, and increase spark
gap until misfire occurs. (for USA
and CDN only)
6. Inspect:
• Sealed portion of spark plug cap
"a"
• Spark plug terminal pin "b"
• Threaded portion of spark plug "c"
7. Inspect:
• Installed condition of spark plug
and spark plug cap
Push in the spark plug cap, mak-
ing sure that it is securely fitted
into the hole in the cylinder head
cover.CHECKING THE COUPLERS AND
LEADS CONNECTION
1. Check:
• Couplers and leads connection
Rust/dust/looseness/short-circuit
→Repair or replace.
CHECKING THE ENGINE STOP
SWITCH
1. Inspect:
• Engine stop switch conduction
Not conductive while it is pushed→
Replace.
Conductive while it is freed→Re-
place.
Set the tester selection position to "Ω
× 1".
CHECKING THE IGNITION COIL
1. Remove the ignition coil cap.
2. Inspect:
• Primary coil resistance
Out of specification→Replace.3. Inspect:
• Secondary coil resistance
Out of specification→Replace.
Disconnect the spark plug cap before
measuring the secondary coil resis-
tance.
CHECKING THE AC MAGNETO
1. Inspect:
• Crankshaft position sensor resis-
tance
Out of specification→Replace.
Minimum spark gap:
6.0 mm (0.24 in)
Tester (+) lead→Black lead "1"
Tester (-) lead→Black lead "2"
Result
Conductive (while the
engine stop switch is
pushed)
Tester (+) lead→Orange lead "1"
Tester (-) lead→Red lead "2"
Primary
coil resis-
tanceTester se-
lector posi-
tion
3.57–4.83
Ω at 20°C
(68°F) Ω × 1
BB
Tester (+) lead→Orange lead "1"
Tester (-) lead→Spark plug termi-
nal "2"
Secondary
coil resis-
tanceTester se-
lector posi-
tion
10.71–14.49
kΩ at 20°C
(68°F) kΩ × 1
Tester (+) lead→Gray lead "1"
Tester (-) lead→Black lead "2"
Crankshaft
position
sensor re-
sistanceTester se-
lector posi-
tion
248–372 Ω
at 20°C
(68°F)Ω × 100
GyB

7-5
IGNITION SYSTEM
2. Inspect:
• Stator coil resistance
Out of specification→Replace.
CHECKING THE ECU
1. Check:
• All electrical components.
2. Check:
• ECU installation status
Make sure that the ECU is in-
stalled correctly.
• The lean angle sensor is built into
the ECU.
• The lean angle sensor stops the en-
gine in case of a turnover.
• To ensure that the lean angle sen-
sor operates correctly, do not
change the installation position of
the sensor.
3. Check:
•ECU
If no fault is found, replace the
ECU. Tester (+) lead→White lead "1"
Tester (-) lead→White lead "2"
Stator coil
resistanceTester se-
lector posi-
tion
0.60–0.90
Ω at 20°C
(68°F)Ω × 10
W1 W2

7-6
THROTTLE POSITION SENSOR SYSTEM
THROTTLE POSITION SENSOR SYSTEM
INSPECTION STEPS
If the throttle position sensor will not operate, use the following inspection steps.
*marked: Refer to "IGNITION SYSTEM" section.
Use the following special tools in this inspection.
Check entire ignition system for connection. No good→Repair or replace.
OK↓
Check throttle position sensor. No good→Replace.
OK↓
*Check AC magneto. No good→Replace.
OK↓
Check ECU. (Throttle position sensor input volt-
age)No good→
Replace.
Model 88 Multimeter with tacometer:
YU-A1927
Digital circuit tester:
90890-03174
Test harness-speed sensor (3P):
YU-03208/90890-03208

7-11
FUEL INJECTION SYSTEM
SENSOR OPERATION TABLE
Diagnos-
tic code
No.ItemActuation or
displayChecking methodActuation or LCD standard display
values
D01 Throttle angle DisplayDisplays the throttle angle. 0–125°
Check with throttle fully closed. When throttle is fully closed:15–19°
Check with throttle fully open. When throttle is fully
opened:95–101 °
D02 Atmosphere DisplayDisplays the atmospheric pres-
sure.
• Measure the atmospheric pres-
sure.0–126 kPa
Displays the atmospheric pressure
according to the elevation and
weather.
Example
0 m above sea level: Approx: 101
kPa
3000 m above sea level:Approx: 70
kPa
D03 Intake air pressure DisplayDisplays the intake air pressure.
• Check the intake manifold pres-
sure.
• Check that the intake air pres-
sure changes while the engine is
being cranked.0–126 kPa
While the engine is stopped: Dis-
plays the atmospheric pressure ac-
cording to the elevation and
weather.
Example
0 m above sea level: Approx: 101
kPa
3000 m above sea level:Approx: 70
kPa
While the engine is being cranked:
Displays the intake air pressure.
D05 Intake air temperature DisplayDisplays the intake air tempera-
ture.
• Check the temperature in the in-
take manifold.-20–100°C
Cold engine: Displayed tempera-
ture is close to the ambient temper-
ature.
Warm engine: Displayed tempera-
ture is approximately 20 °C higher
than the ambient temperature.
D06 Coolant temperature DisplayDisplays the coolant temperature.
• Check the coolant temperature.-20–150°C
Cold engine: Displayed tempera-
ture is close to the ambient temper-
ature.
Warm engine: Displayed tempera-
ture is the current coolant tempera-
ture.
D08 Lean angle sensor DisplayDisplays the lean angle sensor
output voltage.
Remove the ECU and incline it 45°
or more.0–5.0 V
1.0 V: Upright
4.0 V: Overturned
D30 Ignition coil ActuationCheck that power is supplied to
the ignition coil.
• Check that a spark is generated.
• Illuminates the engine trouble
warning light.Actuates the ignition coil for five
times every second.
The "WARNING" LED on the FI di-
agnostic tool comes on each time
the fuel injector is actuated.

7-12
FUEL INJECTION SYSTEM
D36 Injectors ActuationCheck that power is supplied to
the fuel injector.
• Check the fuel injector operation
by listening for the operating
sound or by confirming the oper-
ation visually.Actuates the injector for five times
every second.
The "WARNING" LED on the FI di-
agnostic tool comes on each time
the fuel injector is actuated.
D60EEPROM fault code
display.DisplayDisplays the abnormal portion of
the data in the EEPROM that has
been detected as a fault code No.
44.
If code numbers more than one
are detected, the display alter-
nates every two seconds to show
all the detected code numbers.
When all code numbers are
shown, the display repeats the
same process.00: No fault
01: CO adjustment valve
07: Power Tuner adjustment val-
ues 0–8 for fuel injection amount or
ignition timing
D61Malfunction history
code display.DisplayDisplays the fault code numbers
that are stored in the malfunction
history.
If code numbers more than one
are detected, the display alter-
nates every two seconds to show
all the detected code numbers.
When all code numbers are
shown, the display repeats the
same process.00: No history
12–50: History exists
• Refer to the fault code number.
D62Malfunction history
code erasureActuation
and displayDisplays the total number of mal-
functions, including the current
malfunction, that have occurred
since the history was last erased.
In addition, deletes the fault code
numbers from the history if the cor-
responding items are currently op-
erating normally.00: No history
1–15: History exists
When this diagnostic code number
is selected, fault code numbers for
previously detected malfunctions
are deleted from the history if the
corresponding items are currently
operating normally.
D64 Setting history display DisplayDisplays whether or not history ex-
ists for settings that were made us-
ing the Power Tuner.00: There is no setting history.
01: There is setting history.
02: Whether or not setting history
data exists cannot be determined
(damage to history data).
D65 Setting map erasure DisplayErases the settings that were
made using the Power Tuner.00: There are no settings that were
made using the Power Tuner.
01: There are settings that were
made using the Power Tuner.
D70Program version
numberDisplayCheck the version number of the
program.0–254 Diagnos-
tic code
No.ItemActuation or
displayChecking methodActuation or LCD standard display
values

7-26
FUEL INJECTION SYSTEM
Fault code No. 33
Symptom Ignition system circuit signal is not received properly.
Fail-safe system Unable to start
Unable to drive
Diagnostic code No. D30
FI diagnostic tool display Actuates the ignition coil for five times every second.
The "WARNING" LED on the FI diagnostic tool comes on each time the ignition coil is ac-
tuated.
Checking methodCheck the spark five times.
• Connect an ignition checker.
Item Item/components and probable cause Check or maintenance job Checking method
1 Check the connection and locking condition of
the ignition coil coupler.
Disconnect the coupler and check the pins.
(bent or broken terminals and locking condition
of the pins)Poor connection→ Properly con-
nect, repair, or replace.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 2.
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)Poor connection → Properly con-
nect, repair, or replace.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 3.
3 Continuity of harness Open or short circuit → Replace.
Between Ignition coil coupler and
ECU coupler.
(Orange–Orange)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 4.