July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

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: Engine Coolant Temperature Versus Time Graph (DTC Detection Outline)
Courtesy of MAZDA MOTORS CORP.