The air conditioning system uses a compressor with variable displacement.

The A/C compressor clutch is controlled by the PCM. The HVAC controller sends the A/C request through two different methods depending upon the option content. The firs is through the Class II serial data circuit to the PCM (CJ2). The second is through a 12 volt A/C request signal from the HVAC Controller to the PCM (CJ3, C60). Either signal allows the PCM to manage idle quality, improve wide open throttle performance, and to protect the A/C system from excessively high and low pressures. In addition the PCM will command the cooling fans ON during A/C operation if sufficient A/C pressures or engine coolant temperature have been achieved.

If the A/C refrigerant pressure, and engine operating conditions are within a specific calibrated acceptable ranges the PCM will enable the A/C compressor relay. This is accomplished by providing a ground path for the A/C relay coil within the PCM. When the A/C compressor relay is enabled battery voltage is supplied to the compressor clutch coil.

The PCM controlled air conditioning system uses a variable displacement compressor. The compressor meets the A/C requirements without cycling. For a description of the system and an explanation of the components used, refer to A/C System Description in HVAC.

The A/C electrical system consists of the following components:

The Air Conditioning (A/C) Compressor Control Circuit Diagnosis should be used for diagnosing the electrical portion of the A/C compressor clutch circuit. When diagnosing the refrigerant portion of the HVAC system, the VDOT A/C System Diagnosis should be used. For further system description of the HVAC system refer to HVAC Compressor Controls Circuit Description (CJ3, C60), or HVAC Compressor Controls Circuit Description (CJ2).