Air Conditioning Compressor control (ECC/MCC)

The Climate control module requests compressor activation with an air conditioning selected signal which is sent to the engine control module (ECM). Based on this signal, the signal from the engine coolant temperature, throttle position and the signal from the evaporator temperature sensor the engine control module (ECM) determines when the compressor should work.

The advantage with allowing the engine control module (ECM) to control the Air Conditioning Compressor is that it can delay the compressor switching on slightly, if the idling speed needs to compensate for the extra load for example.