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Engine Coolant Temperature (ECT) Sensor

  1. Ensure ignition is off. Locate ECT sensor. See ENGINE COOLANT TEMPERATURE (ECT) SENSOR LOCATION  table. Remove ECT sensor.
  2. Place probe end of ECT sensor and thermometer in container of water. Attach ohmmeter between ECT sensor terminals. Heat water and note that resistance is within specification in relation to temperature. See Fig 1. Replace ECT sensor if resistance is not within specification.
  3. Using NEW gasket, install ECT sensor. Tighten ECT sensor to 15 ft. lbs. (20 N.m). Fill cooling system.
ENGINE COOLANT TEMPERATURE (ECT) SENSOR LOCATION

Model Location
GS300 Left Front Of Cylinder Head & Contains a Black 2-Pin Connector With Black/Red & Brown Wires
GS400 Near Throttle Body & Contains a Black 2-Pin Connector With Black/Red & Brown Wires
LS400 Near Throttle Body & Contains a Black 2-Pin Connector With Red/Blue & Brown Wires
SC300 Left Front Of Cylinder Head & Contains a Green 2-Pin Connector With Light Green & Brown Wires
SC400 Near Throttle Body & Contains a Green 2-Pin Connector With Light Green & Brown Wires
Fig 1: Testing Engine Coolant Temperature (ECT) Sensor
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