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Home >> Toyota >> 1996 >> Tercel Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Tests W/Codes >> Circuit Tests >> DTC P0115 - Engine Coolant Temperature (ECT) Sensor Circuit >> Diagnosis & Repair
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Diagnosis & Repair

  1. Connect scan tester to DLC3 connector. See Figure. Turn ignition on. Turn on scan tester. Monitor ECT sensor temperature. If temperature displayed is same as actual coolant temperature, inspect component and ECM connections. Problem is intermittent.
  2. If temperature displayed is 284°F (140°C) or more, go to step 5). If temperature displayed is -40°F (-40°C), turn ignition off. Disconnect ECT sensor connector. Connect a jumper wire between ECT sensor wiring harness connector terminals. Turn ignition on. Using scan tester, monitor ECT sensor temperature.
  3. If temperature displayed is 284°F (140°C) or more, replace ECT sensor and retest. If temperature displayed is less than 284°F (140°C), turn ignition off. Remove jumper wire. Access ECM behind glove box. Connect a jumper wire between terminals No. 3 (Green/Black wire) and No. 16 (Brown wire) at ECM E7 connector. See Figure.
  4. If temperature displayed on scan tester is 284°F (140°C) or more, inspect and repair circuits for open between ECT sensor wiring harness connector and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed on scan tester is less than 284°F (140°C), replace ECM and retest.
  5. Turn ignition off. Disconnect ECT sensor connector. Turn ignition on. If temperature displayed on scan tester is -40°F (-40°C), replace ECT sensor and retest. If temperature displayed is not -40°F (-40°C), turn ignition off.
  6. Access ECM behind glove box. Disconnect ECM E7 connector. See Figure. Turn ignition on. If temperature displayed is -40°F (-40°C), inspect and repair circuits between ECT sensor and ECM for short. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed by scan tester is not -40°F (-40°C), replace ECM and retest.
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