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Home >> Toyota >> 2004 >> Matrix Base, FWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 16 (Engine Control System Self-Diagnostics - V6) >> Diagnostic Tests >> DTC P0115: Engine Coolant Temperature Sensor Circuit >> Diagnosis & Repair
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Diagnosis & Repair

WARNING: This page is about a different car, the 2002 Toyota Highlander. However, it is still accessible from the selected car via links, so may be relevant.
  1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3. See Figure. Turn ignition on and then turn hand-held tester or scan tool on. Using hand-held tester or scan tool, monitor ECT sensor temperature. If temperature displayed is same as actual coolant temperature, problem is intermittent. Check component and ECM connections. If temperature displayed is -40°F (-40°C), go to next step. If temperature displayed is 284°F (140°C) or more, go to step  4.
  2. Turn ignition off. Disconnect ECT sensor harness connector (2-pin harness connector with White/Blue wire and White wire). ECT sensor is located on timing belt side of engine, where upper radiator connects. Using a jumper wire, connect ECT sensor harness connector terminals. Turn ignition on. Using hand-held tester or scan tool, monitor ECT sensor temperature. If temperature displayed is less than 284°F (140°C), go to next step. If temperature displayed is 284°F (140°C) or more, replace ECT sensor.
  3. Turn ignition off. Remove jumper wire. Access ECM behind glove box. See Figure. Using a jumper wire, backprobe between terminals No. 14 (White/Blue wire) and No. 18 (White wire) at ECM harness connector E8. See Figure. If temperature displayed is 284°F (140°C) or more, repair open in White/Blue wire and/or White wire between ECT sensor and ECM. See WIRING DIAGRAMS article. If temperature displayed is less than 284°F (140°C), replace ECM.
  4. Turn ignition off. Disconnect ECT sensor harness connector (2-pin harness connector with White/Blue wire and White wire). ECT sensor is located on timing belt side of engine, where upper radiator connects. Turn ignition on. If temperature displayed is not -40°F (-40°C), go to next step. If temperature displayed on is -40°F (-40°C), replace ECT sensor.
  5. Turn ignition off. Access ECM behind glove box. See Figure. Disconnect ECM harness connector E8. See Figure. Turn ignition on. If temperature displayed is -40°F (-40°C), repair short in White/Blue wire between ECT sensor and ECM. See WIRING DIAGRAMS article. If temperature displayed is not -40°F (-40°C), replace ECM.
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