GM Service Manual Online
For 1990-2009 cars only

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 Relay Command: The scan tool displays On or Off. On is displayed when the powertrain control module (PCM) has energized the A/C compressor clutch relay.

PCM - Engine Data 2 - A/C High Side Pressure : The scan tool displays -103 to +3119 kPa (-14 to +452 psi). This parameter represents the A/C refrigerant pressure sensor voltage signal converted to pressure.

PCM - Engine Data 2 - A/C High Side Pressure: The scan tool displays 0-5 volts. The output of the A/C refrigerant pressure sensor.

PCM - Engine Data 2 - A/C Off For WOT: The scan tool displays Yes or No. Yes indicates that the PCM has disabled the A/C compressor, because the throttle position (TP) sensor signal is at wide open throttle.

PCM - Engine Data 2 - A/C Pressure Disable: The scan tool displays Yes or No. Yes is displayed when the system pressure exceeds 3034 kPa (440 psi).

PCM - Engine Data 2 - A/C Request Signal: The scan tool displays Yes or No. Yes is displayed when the HVAC control module is requesting A/C system operation.

PCM - Output Driver Data - A/C Relay Circuit Status: The scan tool displays OK, Fault, or Invalid State. The scan tool indicates the diagnostic state of the A/C relay control circuit.