Checking The Throttle Position Sensor Input Voltage; Checking The Intake Air Pressure Sensor; Checking The Intake Air Temperature Sensor - Yamaha YZ450F Owner's Service Manual

CHECKING THE THROTTLE POSITION
EASB111343
SENSOR INPUT VOLTAGE
1. Check:
• Throttle position sensor input voltage
Out of specification  Replace the ECU.
Throttle position sensor input
voltage
4–6 V
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a. Connect the test harness S-pressure sensor
(3P) to the throttle position sensor coupler
and the wire harness.
b. Connect the pocket tester (20 VDC) to the
test harness S-pressure sensor (3P).
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Test harness S– pressure sensor
(3P)
90890-03207
YU-03207
• Positive tester probe 
Blue "1"
• Negative tester probe 
Black/Blue "2"
c. Start the engine.
d. Measure the throttle position sensor input
voltage.
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CHECKING THE INTAKE AIR PRESSURE EASB111344
SENSOR
1. Check:
• Intake air pressure sensor output voltage
Out of specification  Replace.
Intake air pressure sensor output
voltage
3.57–3.71 V at 101.3 kPa
2
1
ELECTRICAL COMPONENTS
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a. Connect the pocket tester (20 VDC) to the
intake air pressure sensor coupler (wire har-
ness side).
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe 
Pink/Black "1"
• Negative tester probe 
Black/Blue "2"
b. Start the engine.
c. Measure the intake air pressure sensor out-
put voltage.
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EASB111345 CHECKING THE INTAKE AIR TEMPERA-
TURE SENSOR
1. Remove:
• Intake air temperature sensor
(from the air filter case)
EWA
WARNING
• Handle the intake air temperature sensor
with special care.
• Never subject the intake air temperature
sensor to strong shocks. If the intake air
temperature sensor is dropped, replace it.
2. Check:
• Intake air temperature sensor resistance
Out of specification  Replace.
Intake air temperature sensor re-
sistance
290–390  at 80 °C (176 °F)
8-45
P/B
P/B
1
2