Function Explanation (DTC Detection Outline)

• If the engine coolant temperature detected by the ECT sensor No. 1 is not rising 6 °C {11 °F} or more  during a 5 min  period after the engine is started, the PCM determines an ECT sensor No. 1 malfunction and stores a DTC.

Fig 1: ECT Sensor Coolant Temperature/Time Graph

Courtesy of MAZDA MOTORS CORP.