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.
Climate Control Panel -- Inputs -- A/C Off Switch: The scan tool displays Off or On. When the A/C off switch is pressed the scan tool displays On. When released, the scan tool displays Off.Climate Control Panel -- Inputs -- Auto Switch: The scan tool displays Off or On. When the auto switch is pressed the scan tool displays On. When released, the scan tool displays Off.
Climate Control Panel -- Inputs -- Blower Speed Dec. Sw.: The scan tool displays Off or On. When the blower speed decrease switch is pressed the scan tool displays On. When released, the scan tool displays Off.
Climate Control Panel -- Inputs -- Blower Speed Inc. Sw.: The scan tool displays Off or On. When the blower speed increase switch is pressed the scan tool displays On. When released, the scan tool displays Off.
Climate Control Panel -- Inputs -- Defrost Switch: The scan tool displays Off or On. When the defrost switch is pressed the scan tool displays On. When released, the scan tool displays Off.
Climate Control Panel -- Inputs -- De-Ice Switch: The scan tool displays Off or On. When the de-ice switch is pressed the scan tool displays On. When released, the scan tool displays Off.
Climate Control Panel -- Inputs -- Mode Override Dec. Sw.: The scan tool displays Off or On. When the mode override decrease switch is pressed the scan tool displays On. When released, the scan tool displays Off.
Climate Control Panel -- Inputs -- Mode Override Inc. Sw.: The scan tool displays Off or On. When the mode override increase switch is pressed the scan tool displays On. When released, the scan tool displays Off.
Climate Control Panel -- Inputs -- Off Switch: The scan tool displays Off or On. When the off switch is pressed the scan tool displays On. When released, the scan tool displays Off.
Climate Control Panel -- Inputs -- Passenger Cooler Sw.: The scan tool displays Off or On. When the passenger cooler switch is pressed the scan tool displays On. When released, the scan tool displays Off.
Climate Control Panel -- Inputs -- Passenger Warmer Sw.: The scan tool displays Off or On. When the passenger warmer switch is pressed the scan tool displays On. When released, the scan tool displays Off.
Climate Control Panel -- Inputs -- Passenger Zone Switch: The scan tool displays Off or On. When the passenger zone switch is pressed the scan tool displays On. When released, the scan tool displays Off.
Climate Control Panel -- Inputs -- Rear Defog Switch: The scan tool displays Off or On. When the rear defog switch is pressed the scan tool displays On. When pressed again, the scan tool displays Off.
Climate Control Panel -- Inputs -- Recirculate Switch: The scan tool displays Off or On. When the recirculate switch is pressed the scan tool displays On. When released, the scan tool displays Off.
Climate Control Panel -- Module Information 1 -- Calibration ID: The scan tool displays the Calibration ID number for service identification.
Climate Control Panel -- Module Information 1 -- Rom ID: The scan tool displays the ROM ID number for service identification.
Climate Control Panel -- Module Information 2 -- 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 on the Julian Calendar
Climate Control Panel -- Module Information 2 -- Year Module Built: The scan tool displays the year in which the module was built.
Heating and Air Conditioning -- Data -- Act. Dr. Mix Door Pos.: The scan tool displays 0 to 255 counts. The signal output from the feedback potentiometer on the actuator.
Heating and Air Conditioning -- Data -- Act. Pass. Mix Door Pos.: The scan tool displays 0 to 255 counts. The signal output from the feedback potentiometer on the actuator.
Heating and Air Conditioning -- Data -- Com. Dr. Mix Door Pos.: The scan tool displays 0 to 255 counts. The signal output from the feedback potentiometer on the actuator.
Heating and Air Conditioning -- Data -- Com. Pass. Mix Door Pos.: The scan tool displays 0 to 255 counts. The signal output from the feedback potentiometer on the actuator.
Heating and Air Conditioning -- Data -- Commanded Blower: The scan tool displays 0 to 99%. Represents the requested blower speed from the HVAC.
Heating and Air Conditioning -- Data -- Commanded Cooling Fan: The scan tool displays Off, Low or High. Represents the desired state of the engine cooling fan.
Heating and Air Conditioning -- Data -- Coolant Temperature: The scan tool displays -40 to +215°C (-40 to +420°F). The output of the engine coolant temperature sensor. The information is received from the PCM on the class 2 communication link.
Heating and Air Conditioning -- Data -- Driver Mix 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.
Heating and Air Conditioning -- Data -- Dual Zone Pot: The scan tool displays 0-255 counts. Represents the value of the temperature selected with the passenger temperature control.
Heating and Air Conditioning -- Data -- Engine Speed: The scan tool displays 0-16384 RPM. Engine speed is calculated by the PCM and sent to the IPM on the class 2 communication link.
Heating and Air Conditioning -- Data -- Evaporator Inlet Temp.: The scan tool displays -40 to +215°C (-40 to +420°F). The output of the A/C low side thermistor.
Heating and Air Conditioning -- Data -- High Side Temperature: The scan tool displays -40 to +215°C (-40 to +420°F). The output of the A/C high side thermistor.
Heating and Air Conditioning -- Data -- Ignition 0: The scan tool displays 0-25.5 Volts. Represents the voltage at the IPM.
Heating and Air Conditioning -- Data -- Ignition Counter: The scan tool displays 0-50 Counts. The PZM counts each time the ignition is cycled, up to 50 Counts. If any PZM DTC is set, or if the battery voltage is interrupted, the ignition counter resets.
Heating and Air Conditioning -- Data -- In Car Temperature: The scan tool displays -40 to +60°C (-40 to +140°F). The output of the inside air temperature sensor.
Heating and Air Conditioning -- Data -- Outside Temperature: The scan tool displays -40 to +60°C (-40 to +140°F). The output of the ambient air temperature sensor.
Heating and Air Conditioning -- Data -- Passenger Mix Number: The scan tool displays 0-255 counts. This value will vary, depending on the air delivery mode selected and the air discharge temperature selected by the passenger.
Heating and Air Conditioning -- Data -- 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.
Heating and Air Conditioning -- Data -- Rear Blower: The scan tool displays 0-116 Counts. Represents the desired speed of the auxiliary blower motor.
Heating and Air Conditioning -- Data -- Solar Sensor: The scan tool displays 0 to 250 counts. The solar load output of the sunload sensor.
Heating and Air Conditioning -- Data -- Vehicle Speed: the scan tool displays 0-255 km/h (0-158 mph). Represents the vehicle speed, as calculated by the PCM, and sent to the IPM on the class 2 communication link.
Heating and Air Conditioning -- Inputs -- A/C Commanded: The scan tool displays Yes or No. Represents whether the HVAC control panel is requesting A/C operation from the IPM.
Heating and Air Conditioning -- Inputs -- A/C Possible: The scan tool displays Yes or No. Yes is displayed if all system performance limits are met.
Heating and Air Conditioning -- Inputs -- Actual Air Mode: The scan tool displays Normal Purge, A/C Purge, or Cold Purge. Represents the current mode of the discharge air.
Heating and Air Conditioning -- Inputs -- Dual Zone Switch: The scan tool displays On or Off. Represents the current state of the passenger temperature control on the HVAC control panel.
Heating and Air Conditioning -- Inputs -- Hi Refrig. Pressure Sw.: The high pressure switch closes when the A/C systems high pressure limit is approached. The PCM monitors the state of this switch for compressor and auto recirculation operation. The switch closes at a high pressure value which is calibrated for specific platforms. The PCM continuously monitors the high pressure switch when A/C has been selected by the operator.
Heating and Air Conditioning -- Inputs -- Low Refrig. Pressure Sw.: The low pressure switch closes when the A/C systems low pressure limit is approached. The PCM monitors the state of this switch for compressor operation. The switch closes at a low pressure value which is calibrated for specific platforms. The PCM continuously monitors the low pressure switch when A/C has been selected by the operator.
Heating and Air Conditioning -- Inputs -- Selected Air Mode: This data indicates the mode selection knob position. The positions are displayed as follows:
| • | AUTO -- The electronic climate control (ECC) module controls all HVAC air flow. |
| • | BI-LEVEL -- The air flows from the 4 panel vents and the 2 floor vents. |
| • | ECON-A/C-OFF -- Outside air flows from the 4 panel vents. A/C is turned off. |
| • | HEATER/DEFROST -- The air flows from the defrost vent at the top of the instrument panel and the 2 floor vents. |
| • | MAN. A/C -- The air flows from the 4 panel vents. A/C is turned on manually. |
| • | MAN. DEFOG -- The air flows from the defrost vent at the top of the instrument panel and the 2 floor vents. |
| • | MAN. DEFROST -- The air flows from the defrost vent at the top of the instrument panel. |
| • | MAN. HEAT -- The air flows from the 2 floor vents. |
| • | OFF -- The HVAC system is off. |
Heating and Air Conditioning -- Module Information 1-- Rom ID: The scan tool displays the Rom ID number for service identification.
Heating and Air Conditioning -- Module Information 2 -- 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 on the Julian Calendar.
Heating and Air Conditioning -- Module Information 2 -- Year Module Built: The scan tool displays the year in which the module was built.
Heating and Air Conditioning -- Open/Short Data -- Raw Coolant Temperature: The scan tool displays 0-255 Counts, Open, or Short. Represents the raw output value of the coolant temperature sensor. The scan tool will display Open or Short if the circuit is open or shorted.
Heating and Air Conditioning -- Open/Short Data -- Raw Evaporator Temp.: The scan tool displays 0-255 Counts, Open, or Short. Represents the raw output value of the evaporator temperature sensor. The scan tool will display Open or Short if the circuit is open or shorted.
Heating and Air Conditioning -- Open/Short Data -- Raw High Side Temperature: The scan tool displays 0-255 Counts, Open, or Short. Represents the raw output value of the high side temperature sensor. The scan tool will display Open or Short if the circuit is open or shorted.
Heating and Air Conditioning -- Open/Short Data -- Raw Inside Temperature: The scan tool displays 0-255 Counts, Open, or Short. Represents the raw output value of the inside temperature sensor. The scan tool will display Open or Short if the circuit is open or shorted.
Heating and Air Conditioning -- Open/Short Data -- Raw Outside Temperature: The scan tool displays 0-255 Counts, Open, or Short. Represents the raw output value of the outside temperature sensor. The scan tool will display Open or Short if the circuit is open or shorted.
Heating and Air Conditioning -- Open/Short Data -- Raw Solar Sensor: The scan tool displays 0-255 Counts, Open, or Short. Represents the raw output value of the solar sensor. The scan tool will display Open or Short if the circuit is open or shorted.
Heating and Air Conditioning -- Outputs -- A/C Defrost Solenoid: The scan tool displays On or Off. Represents the state of the A/C defrost solenoid.
Heating and Air Conditioning -- Outputs -- Air Down Solenoid: The scan tool displays On or Off. Represents the state of the air down solenoid.
Heating and Air Conditioning -- Outputs -- AIR Up Solenoid: The scan tool displays On or Off. Represents the state of the AIR up solenoid.
Heating and Air Conditioning -- Outputs -- Park Brake Release: The scan tool displays On or Off. Represents the state of the park brake release solenoid.
Heating and Air Conditioning -- Outputs -- Recirculation Solenoid: The scan tool displays On or Off. Represents the state of the recirculation solenoid.
Instrument Panel Cluster -- Data -- Steering Wheel Controls: The scan tool will display the position of the steering wheel switch being depressed or show idle.
Instrument Panel Cluster -- Data -- Steering Wheel Controls: The scan tool will show the counts for each given steering wheel control switch while the switch is depressed.
PCM -- A/C Relay Command: The scan tool displays On or Off. Represents the PCM commanded state of the A/C compressor clutch relay control circuit. The A/C compressor clutch should be engaged when the A/C relay is commanded on.
PCM -- Engine Data 2 -- *A/C High Side Pressure Sensor (If Equipped): The scan tool displays 0.00-5.00 Volts. This parameter represents the A/C refrigerant pressure sensor signal.
PCM--ECT: The scan tool displays -40°C to +150°C (-40°F to +302°F). The engine coolant temperature (ECT) sensor is mounted in the coolant stream. The powertrain control module (PCM) applies 5 volts to the ECT sensor circuit. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold, internal resistance high, the PCM monitors a high signal voltage and interprets it as a cold engine. As the sensor warms, internal resistance decreases, the voltage signal decreases and the PCM interprets the lower voltage as a warm engine.
