Note. If DTC P0115 and DTC P0116 are output together, Engine Coolant Temperature (ECT) sensor circuit may be open. Diagnosis and repair DTC P0115 first. See DTC P0115: ENGINE COOLANT TEMPERATURE SENSOR CIRCUIT .
Note. For component location, see appropriate illustration in THEORY & OPERATION article.
Circuit Description
ECT sensor is a thermistor sensor which monitors water temperature. DTC is set when ECT sensor signal value is out of range during engine operation. Possible causes are
- Defective ECT sensor.
- Defective cooling system.
Diagnostic Aids
Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.