If the theft-deterrent system detects an inappropriate entry into the vehicle, which could result in the vehicle or its contents being stolen, the alarm alerts the surrounding area of an abnormality by sounding the horn and flashing the hazard warning lights.
The system will not function unless it's properly armed. So when you leave the vehicle, follow the arming procedure correctly.
Operation
OperationMazda 6 Owners Manual: Engine coolant temperature (ect) sensor removal/installation
Warning
When the engine is hot, it can badly burn. Turn off the engine and
wait until it is cool before removing the ECT sensor.
1. Drain the engine coolant. (See COOLING SYSTEM SERVICE WARNINGS.)
2. Disconnect the ECT sensor connector.
3. Remove the ECT sensor.
4. Install in the reve ...
Mazda 6 Owners Manual: Scheduled Maintenance (U.S.A., Canada, and Puerto Rico)
Follow Schedule 1 if the vehicle is operated mainly where none of the following
conditions (severe driving conditions) apply.
Repeated short-distance driving
Driving in dusty conditions
Driving with extended use of brakes
Driving in areas where salt or other corrosive materials are used
...