HVAC & climate

HVAC_RECIRC_ON

What it is

Recirculation on/off

Controls the supply of exterior air to the cabin. Recirc “on” means the majority of the airflow into the cabin is originating in the cabin. Recirc “off” means the majority of the airflow into the cabin is coming from outside the car.

This property is defined as VehiclePropertyAccess.READ_WRITE, but OEMs have the option to implement it as VehiclePropertyAccess.READ only.

How the ID is built

A property ID is a 32-bit value packing four fields. Reading 0x15200508 apart:

Field	Mask	Value	Means
Group	0xf0000000	0x10000000	SYSTEM
Area	0x0f000000	0x05000000	SEAT
Type	0x00ff0000	0x00200000	BOOLEAN
Ordinal	0x0000ffff	0x00000508	0x508

Reading it from an app

CarPropertyManager mgr = (CarPropertyManager)
        car.getCarManager(Car.PROPERTY_SERVICE);

boolean value =
        mgr.getBooleanProperty(VehiclePropertyIds.HVAC_RECIRC_ON, areaId);

This property can be read and written, though an OEM may implement it as read-only. It fires a callback whenever the value changes.