Yamaha XT660R Service Manual page 430

EAS00812
3. Coolant temperature sensor
• Remove the coolant temperature sensor
from the engine.
• Connect the pocket tester (Ω × 10) to the
coolant temperature sensor 1 as shown.
• Immerse the coolant temperature sensor
in a container filled with coolant 2.
NOTE:
_
Make sure that the coolant temperature sen-
sor terminals do not get wet.
• Place a thermometer 3 in the coolant.
• Slowly heat the coolant, and then let it cool
to the specified temperature indicated in
the table.
• Check the coolant temperature sensor for
continuity at the temperatures indicated in
the table.
Test Coolant
step temperature
1 20 °C (68 °F)
2 80 °C (176 °F)
3 110 °C (230 °F) 0.140 ~ 0.145 kΩ
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.
Coolant temperature sensor
18 Nm (1.8 m · kg, 13 ft · lb)
SIGNALING SYSTEM
Resistance
2.32 ~ 2.59 kΩ
0.310 ~ 0.326 kΩ
8 - 48
• Does the coolant temperature sensor
operate properly?
YES
EAS00813
4. Wiring
• Check the entire cooling system's wiring.
Refer to "CIRCUIT DIAGRAM".
• Is the cooling system's wiring properly
connected and without defects?
YES
Replace the ECU.
– +
ELEC
NO
Replace the coolant
temperature sensor.
NO
Properly connect or
repair the cooling
system's wiring.