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Home >> Toyota >> 1997 >> Previa LE, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Tests W/Codes >> Circuit Tests >> DTC P0115: Engine Coolant Temperature (ECT) Sensor Circuit >> Diagnosis & Repair

Diagnosis & Repair

  1. Connect scan tool to DLC No. 3 connector. See Figure. Turn ignition on. Using scan tool, monitor ECT sensor temperature. If temperature displayed is same as actual coolant temperature, check 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 tool, 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 under driver's seat. Connect jumper wire between terminals No. 4 (Blue wire) and No. 9 (Brown/Black wire) at ECM E6 connector. See Figure.
  4. If temperature displayed on scan tool is 284°F (140°C) or more, check for open circuit in wiring harness between ECT sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed on scan tool 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 tool 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 under driver's seat. Disconnect ECM E6 connector. See Figure. Turn ignition on. If temperature displayed is -40°F (-40°C), locate and repair short circuit in wiring harness between ECT sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed by scan tool is not -40°F (-40°C), replace ECM and retest.
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