The HVAC Scan Tool Data Definitions contains a brief description of all HVAC related parameters available on the scan tool. The list is in alphabetical order. A given parameter may appear in any one of the data lists. In some cases, the parameter may appear more than once or in more than one data list in order to group certain related parameters together.

PCM -- A/C Clutch Feedback Signal: The scan tool displays Relay Off or Relay On. Represents the status of the relay.

PCM -- A/C Compressor Cycling Switch: The scan tool displays Low Pressure or Normal. This parameter displays the state of the A/C compressor cycling switch. The A/C compressor cycling switch is a normally closed switch.

PCM -- A/C Relay Command: The scan tool displays On or Off. This parameter displays the PCM commanded state of the A/C compressor clutch relay. When the scan tool displays ON, the A/C compressor clutch should be engaged.

PCM -- A/C Request Signal: The scan tool displays Yes or No. The A/C Request Signal displays the state of the A/C request input circuit from the heating, ventilation, and air conditioning (HVAC) controls. The powertrain control module (PCM) uses the A/C request signal in order to determine whether the A/C compressor operation is being requested.