Checking The Coolant Temperature Sensor; Checking The Throttle Position Sensor Input Voltage - Yamaha YZ 2020 Series Owner's Service Manual

EAM30303
CHECKING THE COOLANT TEMPERATURE
SENSOR
1. Remove:
• Coolant temperature sensor
EWA14130
WARNING
• Handle the coolant temperature sensor
with special care.
• Never subject the coolant temperature sen-
sor to strong shocks. If the coolant temper-
ature sensor is dropped, replace it.
2. Check:
• Coolant temperature sensor resistance
Out of specification  Replace.
Coolant temperature sensor re-
sistance
2513–2777  at 20 C (2513–
2777  at 68 F)
Coolant temperature sensor re-
sistance
210–221  at 100 C (210–221 
at 212 F)
a. Connect the digital circuit tester () to the
coolant temperature sensor.
Digital circuit tester (CD732)
90890-03243
Model 88 Multimeter with tachom-
eter
YU-A1927
• Positive tester probe 
Green/White "1"
• Negative tester probe 
Black/Blue "2"
G/W
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.
c. Place a thermometer in the coolant.
B/L
B/L
2
8-55
ELECTRICAL COMPONENTS
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.
EAM30305
CHECKING THE THROTTLE POSITION
SENSOR INPUT VOLTAGE
1. Check:
• Throttle position sensor input voltage
Out of specification  Replace the ECU.
Throttle position sensor input
voltage
4–6 V
a. Connect the test harness S-pressure sen-
sor (3P) to the throttle position sensor cou-
pler and the wire harness.
b. Connect the digital circuit tester (DCV) to
the test harness S-pressure sensor (3P).
Digital circuit tester (CD732)
90890-03243
Model 88 Multimeter with tachom-
eter
YU-A1927
Test harness S– pressure sensor
(3P)
90890-03207
Test harness S– pressure sensor
(3P)
YU-03207
• Positive tester probe 
Blue "1"
• Negative tester probe 
Black/Blue "2"