Air Conditioning (A/C) Compressor.
The A/C compressor transports the refrigerant which is necessary for operating the air conditioning.
The compressor is of the axial piston type with variable displacement. It means that the compressor has adjustable stroke volume and that it is controlled by a control valve (solenoid).
The valve, which is located on the underneath of the compressor, can be replaced.
The A/C compressor is mounted on the cylinder block and is driven by the engine's crankshaft via the auxiliaries belt.
For further information, see Design and Function, Climate Control Module (CCM).