GM Service Manual Online
For 1990-2009 cars only
A/C Refrigerant Pressure Sensor: The scan tool displays 0-3450 kPa (0-500 psi). The voltage applied to the ECM input from the A/C refrigerant pressure sensor is converted to a pressure value.

A/C Refrigerant Pressure Sensor: The scan tool displays 0-5 volts. The voltage applied to the ECM input for the A/C refrigerant pressure sensor.

A/C Relay Command: The scan tool displays Yes/No. The scan tool displays the control decision for the compressor clutch relay output as determined by the ECM.

A/C Request: The scan tool displays Yes/No. The scan tool displays Yes when the HVAC control module requires the A/C compressor clutch to engage. The scan tool displays No when the HVAC control module does not need the A/C compressor clutch to engage.

A/C Request Signal: The scan tool displays Yes/No. The scan tool displays Yes when the ECM receives a class 2 message from the HVAC control module to engage the A/C compressor clutch. The scan tool displays No when the ECM receives a class 2 message from the HVAC control module to disengage the A/C compressor clutch.

Afterblow Option: The scan tool can activate the afterblow feature and will display an * if the feature is activated.

Ambient Air Temp. Sensor: The scan tool displays -40 to 60°C (-40 to 140°F). The voltage applied to the HVAC control module input from the ambient air temperature sensor is converted to an unfiltered temperature value.

Blower Motor Speed: The scan tool displays 0-100 %. The actual blower speed interpreted by the HVAC control module.

Blower Motor Speed Command: The scan tool displays 0-100 %. The blower speed being requested by the HVAC control module.

Calibration ID: The scan tool displays the current level of calibration in the HVAC module.

Compressor Clutch Status: The scan tool displays Off/Auto. The scan tool displays Off when the HVAC control module is not using A/C system for cooling requirements. The scan tool displays Auto when the HVAC control module is using A/C system for cooling requirements.

Driver 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. The higher the program number will relate to a higher heating requirement.

Driver Temp. Dr. Cal. Range: The scan tool displays 0-65535 Pulses. The total calibrated range of the actuator that is stored in the memory of the HVAC control module.

Driver Temp. Dr. Motor Command: The scan tool displays 0-255 Counts. The desired position of the left air temperature actuator.

Driver Temp. Dr. Position: The scan tool displays 0-255 Counts. The signal output from the feedback potentiometer on the left air temperature actuator.

Driver Temp. Dr. Position: The scan tool displays 0-65535 Pulses. The signal output from the feedback potentiometer on the left air temperature actuator.

ECT Sensor: The scan tool range is -40 to +150°C (-40 to +302°F). This parameter indicates the engine coolant temperature based on input from the engine coolant temperature sensor .

Inside Air Temp. Sensor: The scan tool displays -40 to 60°C (-40 to 140°F). The voltage applied to the HVAC control module input for the inside air temperature sensor is converted to a temperature value.

LED Intensity: The scan tool displays 0-255 Counts. This parameter gives an indication of the intensity of the LED of the HVAC control module. The higher the count value the brighter the LED is.

A/C Off for WOT: The scan tool displays Yes/No. The scan tool displays Yes when the ECM recognizes wide open throttle. The scan tool displays No in all other throttle positions.

A/C Pressure Disable: The scan tool displays Yes/No. The scan tool displays Yes when the ECM recognizes an A/C pressure of 4.5 volts (400 psi). The scan tool displays no when less than 4.5 volts (400 psi) is recognized.

Left Sunload Sensor: The scan tool displays 0-255 Counts. The voltage applied to the left sunload input of the HVAC control module is converted to a number between 0-255. A high light intensity will produce a low count value.

Load Management Status: The scan tool displays On/Off. On will be displayed when a low battery condition is detected and one or more accessories have been disabled in order to reduce the electrical load.

Lower Left Duct Temp. Sensor: The scan tool displays 0-255 Counts. The voltage applied to the lower left duct air temperature input of the HVAC control module is converted to a number between 0-255. The higher the duct air temperature the lower the count value.

Lower Right Duct Temp. Sensor: The scan tool displays 0-255 Counts. The voltage applied to the lower right duct air temperature input of the HVAC control module is converted to a number between 0-255. The higher the duct air temperature the lower the count value.

Mode Dr. Cal. Range: The scan tool displays 0-65535 Pulses. The total calibrated range of the actuator that is stored in the memory of the HVAC control module.

Mode Dr. Motor Command: The scan tool displays 0-255 Counts. The desired position of the mode actuator.

Mode Dr. Position: The scan tool displays 0-255 Counts. The signal output from the feedback potentiometer on the mode actuator.

Mode Dr. Position: The scan tool displays 0-65535 Pulses. The signal output from the feedback potentiometer on the mode actuator.

Mode Status: The scan tool displays Off, Auto, Defrost, Heater, Defog, Bi-level and Mid. The scan tool displays the state of mode operation.

Psgr. 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. The higher the program number will relate to a higher heating requirement.

Psgr. Temp. Dr. Cal. Range: The scan tool displays 0-65535 Pulses. The total calibrated range of the actuator that is stored in the memory of the HVAC control module.

Psgr. Temp. Dr. Motor Command: The scan tool displays 0-255 Counts. The desired position of the right air temperature actuator.

Psgr. Temp. Dr. Position: The scan tool displays 0-255 Counts. The signal output from the feedback potentiometer on the right air temperature actuator.

Psgr. Temp. Dr. Position: The scan tool displays 0-65535 Pulses. The signal output from the feedback potentiometer on the right air temperature actuator.

Recirculation Dr. Cal. Range: The scan tool displays 0-65535 Pulses. The total calibrated range of the actuator that is stored in the memory of the HVAC control module.

Recirculation Dr. Motor Command: The scan tool displays 0-255 Counts. The desired position of the recirculation actuator.

Recirculation Dr. Position: The scan tool displays 0-255 Counts. The signal output from the feedback potentiometer on the recirculation actuator.

Recirculation Dr. Position: The scan tool displays 0-65535 Pulses. The signal output from the feedback potentiometer on the recirculation actuator.

Right Sunload Sensor: The scan tool displays 0-255 Counts. The voltage applied to the right sunload input of the HVAC control module is converted to a number between 0-255. A high light intensity will produce a low count value.

Software Part Number: The scan tool displays the current level of software in the HVAC module.

Upper Left Duct Temp. Sensor: The scan tool displays 0-255 Counts. The voltage applied to the upper left duct air temperature input of the HVAC control module is converted to a number between 0-255. The higher the duct air temperature the lower the count value.

Upper Right Duct Temp. Sensor: The scan tool displays 0-255 Counts. The voltage applied to the upper right duct air temperature input of the HVAC control module is converted to a number between 0-255. The higher the duct air temperature the lower the count value.

Valet Switch: The scan tool displays Active/Inactive. This is the actual state of the Valet switch.

Vehicle Speed: The scan tool range is 0-255 km/h (0-158 mph). This parameter indicates the vehicle speed calculated by the ECM from the vehicle speed sensor (VSS).