| Table 1: | HVAC Control Module Scan Tool Data Parameters |
| Table 2: | HVAC Control Module Scan Tool Output Controls |
Parameter | System State | Expected Value | Description |
|---|---|---|---|
Operating Conditions: Engine ON | |||
A/C Compressor Feedback | -- | Varies | The scan tool displays On/Off. The state of the HVAC control module input for the A/C compressor status. When supply voltage is applied to the A/C compressor clutch coil, the voltage is also applied to the input terminal of the HVAC control module and the scan tool displays On. The scan tool displays Off when supply voltage is not applied to the A/C compressor clutch coil. |
A/C Head Pressure | -- | No | The scan tool displays Yes or No. This is the state of the A/C head pressure. |
AC/Heater Door Actual | -- | Varies | The scan tool displays 0-255 Counts. The voltage applied to the HVAC control module input for the mode door position is converted to a number between 0 and 255 where 51 Counts is approximately equal to 1 V. |
AC/Heater Door Commanded | -- | Varies | The scan tool displays 0-255 counts. The scan tool displays the desired mode door position as determined by the HVAC control module. |
AC/Heater Motor Drive | -- | Stop | The scan tool displays Stop, Increase, or Decrease. The scan tool displays the control decision for the actuator output as determined by the HVAC control module. |
AC Permission | -- | Granted | The scan tool displays Granted or Withheld. |
A/C Switch | -- | Off | The scan tool displays Off or On. This is the state of the A/C switch. |
Air Inlet Door Actual | -- | Varies | This displays Counts. This is the current numeric value of the air inlet door as monitored by the HVAC module. |
Air Inlet Door Commanded | -- | Varies | This displays Counts. This is the numeric value of the air inlet door as commanded by the HVAC module. |
Air Inlet Motor Drive | -- | Varies | The scan tool displays Stop, Increase, or Decrease. This is the state of the air inlet motor. |
Air Mix Door Left Commanded | -- | Varies | The scan tool displays 0-255 counts. The scan tool displays the desired left air temperature door position as determined by the HVAC control module. |
Air Mix Door Right Commanded | -- | Varies | The scan tool displays 0-255 counts. The scan tool displays the desired right air temperature door position as determined by the HVAC control module. |
Auto Switch | -- | Off | The scan tool displays Off or On. This is the state of the auto switch. |
Battery Voltage | -- | Normal | The scan tool displays Normal or Out of Range. This is the state of the system voltage. |
Blower Motor PWM Speed | -- | Varies | This displays percent. This is the percentage of power supplied to the blower motor. |
Blower Speed | -- | No | The scan tool displays Yes or No. This is the state of the blower motor speed. |
Defrost Door Actual | -- | Varies | The scan tool displays 0-255 counts. The voltage applied to the defrost door position input of the HVAC control module is converted to a number between 0 and 255 where 51 Counts is approximately equal to 1 V. |
Defrost Door Commanded | -- | Varies | The scan tool displays 0-255 counts. The scan tool displays the desired defrost door position as determined by the HVAC control module. |
Defrost Motor Drive | -- | Stop | The scan tool displays Stop, Increase, or Decrease. The scan tool displays the control decision for the actuator output as determined by the HVAC control module. |
Engine Coolant Temp | -- | No | The scan tool displays Yes or No. This is the state of the engine coolant temperature. |
Engine Running | -- | Yes | The scan tool displays Yes or No. Yes is displayed if the engine is running. |
Fan Down Button | -- | Off | The scan tool displays Off or On. This is the state of the fan down button. |
Fan Up Button | -- | Off | The scan tool displays Off or On. This is the state of the fan up switch. |
Front Defrost Switch | -- | Off | The scan tool displays Off or On. This is the state of the front defrost switch. |
Ign. Since Current DTC | -- | Varies | This displays a numeric value. This is the number of ignition cycles since the current HVAC module DTC. |
Inside Air Temp. | -- | Varies | This displays °C (°F). This is the current temperature of the vehicle interior. |
Inside Air Temp. Fan | -- | On | The scan tool displays On/Off. The scan tool displays the control decision for the fan motor output as determined by the HVAC control module. The fan motor is internal to the inside air temperature sensor assembly. |
Left Mix Door Actual | -- | Varies | The scan tool displays 0-255 counts. The voltage applied to the left air temperature door position input of the HVAC control module is converted to a number between 0 and 255 where 51 Counts is approximately equal to 1 V. |
Left Mix Motor Drive | -- | Stop | The scan tool displays Stop, Increase, or Decrease. The scan tool displays the control decision for the actuator output as determined by the HVAC control module. |
Left Temp. Setting | -- | Varies | This displays °C (°F). This is the temperature setting of the driver side area. |
LH AC Duct Actual | -- | Varies | This displays counts. This is the numeric actual value of the driver side duct area |
LH AC Duct Desired | -- | Varies | This displays counts. This is the numeric desired value of the driver side duct area |
LH Heater Duct Actual | -- | Varies | This displays counts. This is the numeric actual value of the driver side duct area. |
LH Heater Duct Desired | -- | Varies | This displays counts. This is the numeric desired value of the driver side duct area. |
Mode Switch | -- | Off | The scan tool displays Off or On. This is the state of the mode switch. |
Mode Select Position | -- | Off | The scan tool displays Off, Auto, Defrost, Heater, Htr./Def., Bi-Level or Panel. This is the current position of the HVAC mode select. |
Mode Switch Pos. | -- | Varies | The scan tool displays Invalid, Auto, Panel, Bi-Level, Heater, Htr./Def. or Defrost. This is the state of the HVAC mode switch. |
Off Switch | -- | Off | The scan tool displays Off or On. This is the state of the off switch. |
Outside Air Temp. | -- | No | The scan tool displays Yes/No. The scan tool displays Yes when the HVAC control module interprets the input of the ambient air temperature sensor is at or below 1°C (35°F). This action disables an A/C request. The scan tool displays No when the HVAC control module interprets the input of the ambient air temperature sensor is above 1°C (35°F). |
Outside Air Temp. Filtered | -- | Varies | This displays °C (°F). This is the filtered value of the outside air temperature. |
Outside Air Temp. Raw | -- | Varies | This displays °C (°F). This is the raw value of the outside air temperature. |
Pressure Cycle Switch | -- | Varies | The scan tool displays Low Pressure/Normal. The current state of the input from the A/C low pressure switch. The scan tool displays Low Pressure when the switch is open and displays Normal when the switch is closed. The low pressure switch opens when low side pressure decreases to approximately 151 kPa (22 psi) and closes when the low side pressure increases to approximately 275 kPa (40 psi). |
Pressure Cycle Switch | -- | No | The scan tool displays Yes/No. The scan tool displays Yes when the HVAC control module interprets the input of the A/C low pressure switch is not grounded. This action disables an A/C request. The scan tool displays No when the HVAC control module interprets the input of the A/C low pressure switch is grounded. |
Rear Defrost Switch | -- | Off | The scan tool displays Off or On. This is the state of the rear defrost switch. |
Recirculate Switch | -- | Off | The scan tool displays On or Off. This is the state of the recirculation switch. |
RH AC Duct Actual | -- | Varies | This displays counts. This is the numeric actual value of the passenger side duct area. |
RH AC Duct Desired | -- | Varies | This displays counts. This is the numeric desired value of the passenger side duct area. |
RH Heater Duct Actual | -- | Varies | This displays counts. This is the numeric actual value of the passenger side duct area. |
RH Heater Duct Desired | -- | Varies | This displays counts. This is the numeric desired value of the passenger side duct area. |
Right Mix Door Actual | -- | Varies | The scan tool displays 0-255 counts. The voltage applied to the right air temperature door position input of the HVAC control module is converted to a number between 0 and 255 where 51 Counts is approximately equal to 1 V. |
Right Mix Motor Drive | -- | Stop | The scan tool displays Stop, Increase, or Decrease. The scan tool displays the control decision for the actuator output as determined by the HVAC control module. |
Right Temp. Setting | -- | Varies | This displays °C (°F). This is the temperature setting of the passenger side area. |
Output Control | Description |
|---|---|
A/C Request | This command allows you to turn the A/C Relay On and Off. When the A/C Relay is commanded On, the A/C compressor clutch should be engaged. |
Air Inlet Door | When Outside is selected, the HVAC control module commands the recirculation actuator toward the outside air position. When Recirc is selected, the HVAC control module commands the recirculation actuator toward the recirculation position. This is shown through a command of On and Off. |
Blower Motor | When ON is selected, the HVAC control module commands the blower motor relay ON and a command to increase or decrease air. When OFF is selected, the HVAC control module commands the blower motor relay OFF. |
Inside Air Temp. Sensor Fan | When you select OFF, the HVAC control module commands the inside air temperature fan OFF. The fan remains OFF until you select ON. The normal state of the inside air temperature fan is ON. |
Instant OAT Update | This command updates the outside air temperature. |
Left Temp. Door Position | This commands the right temperature door position from Cold to Hot. |
Mode 1 Door Position | When you select ON, the HVAC control module commands the mode actuator toward the maximum door position. The actuator moves the door to the panel position. When you select OFF, the HVAC control module commands the mode actuator toward the minimum door position. The actuator moves the door to the floor position. |
Mode 2 Door Position | When you select ON, the HVAC control module commands the defroster actuator toward the maximum door position. The actuator moves the door to the defrost position. When you select OFF, the HVAC control module commands the defroster actuator toward the minimum door position. The actuator moves the door in the opposite direction of the defrost position. |
Power Down Now | This output control lets you shutdown the HVAC module. |
Recalibrate All Motors | When ON is selected, all air temp and mode actuators have the capability to perform a recalibration. |
Right Temp. Door Position | This commands the right temperature door position from Cold to Hot. |
