Checking The Coolant Temperature Sensor; Checking The Throttle Position Sensor - Yamaha YZ250F Owner's Service Manual

CHECKING THE COOLANT TEMPERATURE
EAS1SM5344
SENSOR
1. Remove:
• Coolant temperature sensor
EWA14130
WARNING
• Handle the coolant temperature sensor
with special care.
• Never subject the coolant temperature
sensor to strong shocks. If the coolant
temperature sensor is dropped, replace it.
2. Check:
• Coolant temperature sensor resistance
Out of specification  Replace.
Coolant temperature sensor re-
sistance
2.51–2.78 k at 20 °C (68 °F)
210–221  at 100 °C (212 °F)
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a. Connect the pocket tester (  1k/100) to
the coolant temperature sensor.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe 
Green/White "1"
• Negative tester probe 
Black/Blue "2"
G/W
1
b. Immerse the coolant temperature sensor in
a container filled with coolant.
TIP
Make sure the coolant temperature sensor ter-
minals do not get wet.
B/L
G/W B/L
2
ELECTRICAL COMPONENTS
c. Place a thermometer in the coolant.
d. Slowly heat the coolant, and then let it cool
to the specified temperature indicated in the
table.
e. Check the coolant temperature sensor for
continuity at the temperatures indicated in
the table.
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CHECKING THE THROTTLE POSITION EAS1SM5345
SENSOR
1. Remove:
• Throttle position sensor
(from the throttle body)
EWA1DX1009
WARNING
• Handle the throttle position sensor with
special care.
• Never subject the throttle position sensor
to strong shocks. If the throttle position
sensor is dropped, replace it.
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