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Coolant Temperature Sensor

  1. Ensure engine temperature is greater than 176°F (80°C). Remove harness connector from coolant temperature sensor. Connect ohmmeter between sensor harness connector terminal No. 1 and engine ground, then connect between terminal No. 2 and engine ground. Ensure readings at the terminals are as specified. Refer to the COOLANT TEMPERATURE SENSOR  table for specifications.
  2. Using voltmeter, check voltage between harness connector terminal No. 1 and ground, and terminal No. 2 and ground. Both voltage readings should be 4.5-5.5 volts with ignition on. If voltage is not present, repair break in wiring. If wiring is okay, replace control unit (FICU or ICU) connected to temperature sensor.
COOLANT TEMPERATURE SENSOR

Temperature Ohms
32°F (0°C) 5000-6000
72°F (21°C) 2000-2500
147°F (60°C) 700-900
212°F (100°C) 170-220
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