Scan Tool Data Definitions

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.

DDM - Data - Pass. HVAC Switch

The scan tool displays counts. A count number is shown for each right air temperature switch assembly command.

DIM - A/C Information - A/C Clutch (actual)

The scan tool displays On or Off. On is displayed when the PCM has energized the A/C compressor clutch relay.

DIM - A/C Information - A/C Clutch (desired)

The scan tool displays On or Off. On is displayed when the IPM is requesting A/C system operation and the DIM has determined that none of the system performance limits are exceeded.

DIM - A/C Information - A/C Pressure

The scan tool displays 0-4000 kPa (0-580 psi). The output of the A/C refrigerant pressure sensor provided by the PCM over the Class 2 communication link.

DIM - A/C Information - Clutch Voltage

The scan tool displays Low or Normal. Low is displayed when the battery voltage is low, such that A/C compressor clutch slippage is possible.

DIM - A/C Information - Control Head (desired)

The scan tool displays On or Off. On is displayed when the IPM is requesting A/C system operation.

DIM - A/C Information - Pressure Status

The scan tool displays Low, Normal or High. Normal must be displayed to allow A/C operation.

DIM - A/C Information - Temperature Status

The scan tool displays Hot or OK. Hot is displayed when engine coolant temperature rises above 121°C (250°F). OK must be displayed to allow A/C operation.

DIM - Inputs - Steering Wheel Controls

The scan tool displays counts. A count number is shown for each steering wheel command.

IPM - HVAC Door Calibrations - Max Air Inlet Dr Pos

The scan tool displays 0-255 Counts (0-5.00 Volts). The maximum travel range when driven to the stop during Recalibrate All Motors command.

IPM - HVAC Door Calibrations - Max Htr./Def./A/C Dr. Pos.

The scan tool displays 0-255 Counts (0-5.00 Volts). The maximum travel range when driven to the stop during Recalibrate All Motors command.

IPM - HVAC Door Calibrations - Max Left Temp Dr Pos

The scan tool displays 0-255 Counts (0-5.00 Volts). The maximum travel range when driven to the stop during Recalibrate All Motors command.

IPM - HVAC Door Calibrations - Max Right Temp Dr Pos

The scan tool displays 0-255 Counts (0-5.00 Volts). The maximum travel range when driven to the stop during Recalibrate All Motors command.

IPM - HVAC Door Calibrations - Min Air Inlet Dr Pos

The scan tool displays 0-255 Counts (0-5.00 Volts). The minimum travel range when driven to the stop during Recalibrate All Motors command.

IPM - HVAC Door Calibrations - Min Htr./Def./A/C Dr. Pos.

The scan tool displays 0-255 Counts (0-5.00 Volts). The minimum travel range when driven to the stop during Recalibrate All Motors command.

IPM - HVAC Door Calibrations - Min Left Temp Dr Pos

The scan tool displays 0-255 Counts (0-5.00 Volts). The minimum travel range when driven to the stop during Recalibrate All Motors command.

IPM - HVAC Door Calibrations - Min Right Temp Dr Pos

The scan tool displays 0-255 Counts (0-5.00 Volts). The minimum travel range when driven to the stop during Recalibrate All Motors command.

IPM - HVAC Door Positions - Air Inlet Dr Actual

The scan tool displays 0-255 Counts (0-5.00 Volts). The signal output from the feedback potentiometer on the recirculation actuator.

IPM - HVAC Door Positions - Air Inlet Dr Commanded

The scan tool displays 0-255 Counts (0-5.00 Volts). The desired position of the recirculation actuator.

IPM - HVAC Door Positions - Htr./Def./A/C Dr Actual

The scan tool displays 0-255 Counts (0-5.00 Volts). The signal output from the feedback potentiometer on the mode actuator.

IPM - HVAC Door Positions - Htr./Def./A/C Dr Commanded

The scan tool displays 0-255 Counts (0-5.00 Volts). The desired position of the mode actuator.

IPM - HVAC Door Positions - Left Temp Dr Actual

The scan tool displays 0-255 counts (0 to 5 volts). The signal output from the feedback potentiometer on the left air temperature actuator.

IPM - HVAC Door Positions - Left Temp. Dr. Commanded

The scan tool displays 0-255 Counts (0-5.00 Volts). The desired position of the left air temperature actuator.

IPM - HVAC Door Positions - Right Temp Dr Actual

The scan tool displays 0-255 Counts (0-5.00 Volts). The signal output from the feedback potentiometer on the right air temperature actuator.

IPM - HVAC Door Positions - Right Temp. Dr. Commanded

The scan tool displays 0-255 Counts (0-5.00 Volts). The desired position of the right actuator.

IPM - HVAC Sensors - Inside Air Temp

The scan tool displays -40 to 60°C (-40 to 140°F). The output of the inside air temperature sensor.

IPM - HVAC Sensors - Left AC Duct Temp

The scan tool displays -40 to 150°C (-40 to 300°F). The output of the upper left air temperature sensor.

IPM - HVAC Sensors - Left Duct Temp Desired

The scan tool displays -18 to 120°C (0 to 250°F). The target LH duct temperature that the HVAC system is trying to achieve.

IPM - HVAC Sensors - Left Htr. Duct Temp

The scan tool displays -40 to 150°C (-40 to 300°F). The output of the lower left air temperature sensor.

IPM - HVAC Sensors - Left Solar

The scan tool displays 0-255 counts. The solar load output of the sunload sensor assembly.

IPM - HVAC Sensors - Outside Air Temp

The scan tool displays -40 to 60°C (-40 to 140°F). The output of the outside air temperature sensor.

IPM - HVAC Sensors - Right AC Duct Temp

The scan tool displays -40 to 150°C (-40 to 300°F). The output of the upper right air temperature sensor.

IPM - HVAC Sensors - Right Duct Temp Desired

The scan tool displays -18 to 120°C (0 to 250°F). The target RH duct temperature that the HVAC system is trying to achieve.

IPM - HVAC Sensors - Right Htr. Duct Temp

The scan tool displays -40 to 150°C (-40 to 300°F). The output of the lower right air temperature sensor.

IPM - HVAC Sensors - Right Solar

The scan tool displays 0-255 counts. The solar load output of the sunload sensor assembly.

IPM - HVAC System Data - A/C Requested

The scan tool displays Yes or No. The message sent out on class 2 communication link to the PCM when A/C is requested.

IPM - HVAC System Data - Commanded Blower

The scan tool displays 0 to 100%.

IPM - HVAC System Data - Coolant Temperature

The scan tool displays -40 to 120°C (-40 to 250°F). The information is received from the PCM on the class 2 communication link.

IPM - HVAC System Data - Left Program Number

The scan tool displays 0-255 counts. This value will vary, depending on the air delivery mode and the air discharge temperature selected by the driver.

IPM - HVAC System Data - Load Reduction Active

The scan tool displays Yes or No. Yes will be displayed when a low battery condition is detected and one or more accessories (blower motor, A/C compressor clutch, etc.) has been disabled in order to reduce the electrical load.

IPM - HVAC System Data - Right Program Number

The scan tool displays 0-255 counts. This value will vary, depending on the air delivery mode and the air discharge temperature selected by the passenger.

IPM - HVAC System Data - Selected Air Mode

The scan tool displays: Auto/Upper/Bi-Level/Heater/Defog/Defrost. This data indicates the discharge air mode selected. The positions are displayed as follows:

• AUTO - The Instrument Panel Integration Module (IPM) controls all HVAC air flow.
• UPPER - The air flows from the 4 upper vents.
• BI-LEVEL - The air flows from the 4 panel vents and the 2 floor vents.
• HEATER - The air flows from the 2 floor vents.
• DEFOG - The air flows from the defrost vent at the top of the instrument panel and the 2 floor vents.
• DEFROST - The air flows from the defrost vent at the top of the instrument panel.

IPM - HVAC System Data - System Program Number

The scan tool displays 0-255 counts. This value will vary, depending on the air delivery mode and the air discharge temperatures selected by the driver and passenger.

IPM - HVAC System Data - Vehicle Speed

The scan tool displays 0-249 km/h (0-155 mph). This value is used to calculate the outside air temperature when the vehicle is moving.

IPM - Module Information - 8 Digit GM Part Number

The scan tool displays the part number for service identification.

IPM - Module Information - Calibration ID

The scan tool displays the Calibration ID number for service identification.

IPM - Module Information - Component Serial Number

The scan tool displays a 4 digit number.

IPM - Module Information - Julian Date of Build

The scan tool displays a 3 digit number. An example would be 256. 256 is September 12, which is day 256 based on the Julian Calendar.

IPM - Module Information - PROM ID

The scan tool displays the PROM ID number for service identification.

IPM - Module Information - Year Module Built

The scan tool displays a 4 digit number representing the year in which the module was built.

IPM - Open/Short Data - Inside Air Temp

The scan tool displays 0-255 Counts (0-5.00 Volts). The status of the sensor signal circuit is monitored. 0 counts indicates a short to ground, 255 counts indicates an open circuit.

IPM - Open/Short Data - Left AC Duct Temp

The scan tool displays 0-255 Counts (0-5.00 Volts). The status of the sensor signal circuit is monitored. 0 counts indicates a short to ground, 255 counts indicates an open circuit.

IPM - Open/Short Data - Left Htr. Duct Temp

The scan tool displays 0-255 Counts (0-5.00 Volts). The status of the sensor signal circuit is monitored. 0 counts indicates a short to ground, 255 counts indicates an open circuit.

IPM - Open/Short Data - Left Solar Sensor

The scan tool displays 0-255 counts. The status of the sensor signal circuit is monitored. 0 counts indicates a short to ground, 255 counts indicates an open circuit.

IPM - Open/Short Data - Outside Air Temp

The scan tool displays 0-255 Counts (0-5.00 Volts). The status of the sensor signal circuit is monitored. 0 counts indicates a short to ground, 255 counts indicates an open circuit.

IPM - Open/Short Data - Right AC Duct Temp

The scan tool displays 0-255 Counts (0-5.00 Volts). The status of the sensor signal circuit is monitored. 0 counts indicates a short to ground, 255 counts indicates an open circuit.

IPM - Open/Short Data - Right Htr. Duct Temp

The scan tool displays 0-255 Counts (0-5.00 Volts). The status of the sensor signal circuit is monitored. 0 counts indicates a short to ground, 255 counts indicates an open circuit.

IPM - Open/Short Data - Right Solar Sensor

The scan tool displays 0-255 counts. The status of the sensor signal circuit is monitored. 0 counts indicates a short to ground, 255 counts indicates an open circuit.

PCM - A/C Request Signal

The scan tool displays Yes or No. The PCM uses the A/C request signal in order to determine if A/C compressor operation is being requested by the HVAC control module.

PCM - EGR Data - A/C Relay Command

The scan tool displays On or Off. On is displayed when the PCM has energized the A/C compressor clutch relay.

PCM - Engine Data 1 - A/C Relay Command

The scan tool displays On or Off. On is displayed when the PCM has energized the A/C compressor clutch relay.

PCM - Engine Data 2 - A/C Relay Command

The scan tool displays On or Off. On is displayed when the PCM has energized the A/C compressor clutch relay.

PCM - Engine Data 2 - A/C High Side Pressure

The scan tool displays 0 to 5 volts. The output of the A/C refrigerant pressure sensor.

PCM - Engine Data 2 - A/C High Side Pressure

The scan tool displays 0 to 4000 kPa (0 to 580 psi). 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 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 2968 kPa (430 psi).

PCM - Misfire Data - A/C Relay Command

The scan tool displays On or Off. On is displayed when the PCM has energized the A/C compressor clutch relay.

PCM - Output Driver Data - A/C Relay Circuit Status

The scan tool displays OK or Fault. Fault is displayed when an open or short is detected in the A/C compressor clutch relay ground circuit.