Scan Tool Data Definitions
HVAC - Primary ECC Data - Outside Air Temp: The scan tool displays -40 to +60°C (-40 to + 140°F). The output of the ambient air temperature sensor.
HVAC - Primary ECC Data - Inside Air Temp: The scan tool displays -40 to +60°C (-40 to + 140°F). The output of the inside air temperature sensor.
HVAC - Primary ECC Data - Upper Outlets Duct Temp: The scan tool displays -40 to + 150°C (-40 to +300°F). The output of the upper outlets duct temperature sensor.
HVAC - Primary ECC Data - Lower Outlets Duct Temp: The scan tool displays -40 to + 150°C (-40 to +300°F). The output of the lower outlets duct temperature sensor.
HVAC - Auxiliary ECC Data - Aux. Inside Air Temp: The scan tool displays -40 to + 150°C (-40 to +300°F). The output of the Aux. inside air temperature sensor.
HVAC - Auxiliary ECC Data - Aux. Upper Outlet Temp: The scan tool displays -40 to + 150°C (-40 to +300°F). The output of the Aux. Upper Outlet temperature sensor.
HVAC - Auxiliary ECC Data - Aux. Lower Outlet Temp: The scan tool displays -40 to +150°C (-40 to +300°F). The output of the Aux. Lower Outlet temperature sensor.
HVAC - Primary ECC Data - Solar Sensor: The scan tool displays 0-250 counts. The solar load output of the sunload sensor.
HVAC - Primary ECC Data - Blower Motor PWM Speed: The scan tool displays 0-98%.
HVAC -Auxiliary ECC Data - Auxiliary Blower Motor PWM: The scan tool displays 0-98%.
HVAC - Primary ECC Data - Mode Selection Position: The scan tool displays AUTO, Upper, Defog, Bi-Level, Heater or Defrost. The current operating mode of the HVAC system.
HVAC - Primary ECC Data - A/C Request: The scan tool displays Yes or No.
HVAC - Primary ECC Data - A/C LED On: The scan tool displays on or off.
HVAC - Primary ECC Data - Recirc LED: The scan tool displays on or off.
HVAC - Primary ECC Data - Outside Air LED: The scan tool displays on or off.
HVAC - Primary ECC Data - Rear Defog: The scan tool displays on or off.
HVAC - Primary ECC Data - Mode Door Actual: The scan tool displays 0-255 counts. The signal output from the feedback pot on the actuator.
HVAC - Primary ECC Data - Mode Door Commanded: The scan tool displays 0-255 counts. The desired position of the actuator.
HVAC - Primary ECC Data - Mode Door Max. Position: The scan tool displays 0-255 counts. The maximum travel range when driven to the door stop during a recalibration.
HVAC - Primary ECC Data - Mode Door Min. Position: The scan tool displays 0-255 counts. The minimum travel range when driven to the door stop during a recalibration.
HVAC - Auxiliary ECC Data - Aux. Mode Door Actual: The scan tool displays 0-255 counts. The signal output from the feedback pot on the actuator.
HVAC - Auxiliary ECC Data - Aux. Mode Door Commanded: The scan tool displays 0-255 counts. The desired position of the actuator.
HVAC - Auxiliary ECC Data - Aux. Mode Door Max. Position: The scan tool displays 0-255 counts. The maximum travel range when driven to the door stop during a recalibration.
HVAC -Auxiliary ECC Data - Aux. Mode Door Min. Position: The scan tool displays 0-255 counts. The minimum travel range when driven to the door stop during a recalibration.
HVAC - Primary ECC Data - Air Inlet Door Actual: The scan tool displays 0-255 counts. The signal output from the feedback pot on the actuator.
HVAC - Primary ECC Data - Air Inlet Door Commanded: The scan tool displays 0-255 counts. The desired position of the actuator.
HVAC - Primary ECC Data - Air Inlet Door Max.: The scan tool displays 0-255 counts. The maximum travel range when driven to the door stop during a recalibration.
HVAC - Primary ECC Data - Air Inlet Door Min.: The scan tool displays 0-255 counts. The minimum travel range when driven to the door stop during a recalibration.
HVAC - Primary ECC Data - Air Mix Door Actual: The scan tool displays 0-255 counts. The signal output from the feedback pot on the actuator.
HVAC - Primary ECC Data - Air Mix Door Commanded: The scan tool displays 0-255 counts. The desired position of the actuator.
HVAC - Primary ECC Data - Air Mix Door Max. Position: The scan tool displays 0-255 counts. The maximum travel range when driven to the door stop during a recalibration.
HVAC - Primary ECC Data - Air Mix Door Min. Position: The scan tool displays 0-255 counts. The minimum travel range when driven to the door stop during a recalibration.
HVAC - Auxiliary ECC Data - Aux. Mix Door Actual: The scan tool displays 0-255 counts. The signal output from the feedback pot on the actuator.
HVAC - Auxiliary ECC Data - Aux. Mix Door Commanded: The scan tool displays 0-255 counts. The desired position of the actuator.
HVAC - Auxiliary ECC Data - Aux. Mix Door Max. Position: The scan tool displays 0-255 counts. The maximum travel range when driven to the door stop during a recalibration.
HVAC - Auxiliary ECC Data - Aux. Mix Door Min. Position: The scan tool displays 0-255 counts. The minimum travel range when driven to the door stop during a recalibration.
HVAC - Miscellaneous Tests - Instant OAT Update: The scan tool displays Commanded State: The scan tool displays Commanded State: None or On. Updates the ECC outside air temperature input to the current raw value.
HVAC - Miscellaneous Tests - Blower Motor: The scan tool displays Commanded State: None, Off or On. This function allows you to command the blower motor to its maximum (100%) or minimum (0%) speeds.
HVAC -Special Functions - Set Up New HVAC: This function has the ECC relearn a new heater and A/C control.
PCM - A/C Information - A/C Clutch Feedback Signal: The scan tool displays On or Off. On is displayed when the PCM has energized the A/C clutch relay.
PCM - Engine Data 1 - ECT: The scan tool displays -40 to +215°C (-40 to +420°F). The output of the engine coolant temperature sensor.
PCM - Engine Data 2 - ECT: The scan tool displays -40 to +215°C (-40 to +420°F). The output of the engine coolant temperature sensor.
PCM - Engine Data 2 - Commanded A/C: The scan tool displays On or Off. On is displayed when the PCM has energized the A/C clutch relay.
PCM - Engine Data 2 - A/C Compressor Cycling Switch: The scan tool displays Normal and Low Pressure. The output of the A/C pressure sensor.
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 the PCM to turn on the compressor clutch.
PCM - Engine Data 2 - A/C High Pressure Recirculation Switch: The scan tool displays OK or Low Pressure. Displays the output of the High Pressure Recirculation Switch.
Scheme 152
Circuit Description
The HVAC control module monitors the outside ambient air temperature via an ambient air temperature sensor. When the air is cold, the sensor resistance voltage and the signal voltage are high. When the air is warm, the sensor resistance voltage and the signal voltage are low.
Conditions for Running the DTC
The ignition is turned ON.
Conditions for Setting the DTC
The HVAC control module detects that the signal circuit is out of the range 0.09-5.0 volts.
Action Taken When the DTC Sets
A default value will be used for the sensor data by the HVAC control module. The sensor reading, which displays on the scan tool in the HVAC data list, will be the default value.
Conditions for Clearing the DTC
- The DTC will become history if the HVAC control module no longer detects a condition.
- The history DTC clears after 50 fault free ignition cycles.
- The history DTC clears after 50 fault free ignition cycles.
- The DTC can be cleared with a scan tool.
Diagnostic Aids
If the conditions is not present, refer to TESTING FOR INTERMITTENT & POOR CONNECTIONS .
The HVAC control module monitors the passenger compartment inside air temperature through an inside air temperature sensor assembly. When the air is cold, the sensor resistance and the signal voltage are high. When the air is warm, the sensor resistance and the signal voltage are low.
The ignition is turned ON.
The HVAC control module detects the signal circuit is out of the range 0.09-5.0 volts.
A default value will be used for the sensor data by the HVAC control module. The sensor reading, which displays on the scan tool in the HVAC data list, will be this default value.
- The DTC will become history if the HVAC control module no longer detects a condition.
- The history DTC clears after 50 fault free ignition cycles.
- The DTC can be cleared with a scan tool.
If the condition is not present, refer to TESTING FOR INTERMITTENT & POOR CONNECTIONS .
The HVAC control module monitors the air temperature in the upper center A/C discharge duct via an upper air temperature sensor. When the air is cold, the sensor resistance and the signal voltage are high. When the air is warm, the sensor resistance and the signal voltage are low.
The ignition is turned ON.
The HVAC control module detects the signal circuit is less than 5 Counts (0.09 V) or greater than 250 Counts (4.90 V).
A default value will be used for the sensor data by the HVAC control module. The actual value of the sensor will be displayed on the scan tool.
- The DTC will become history if the HVAC control module no longer detects a condition.
- The history DTC clears after 50 fault free ignition cycles.
- The DTC can be cleared with a scan tool.
If the condition is not present, refer to TESTING FOR INTERMITTENT & POOR CONNECTIONS .
The HVAC control module monitors the air temperature in the floor discharge duct via a lower air temperature sensor. When the air is cold, the sensor resistance and the signal voltage are high. When the air is warm, the sensor resistance and the signal voltage are low.
The ignition is turned ON.
The HVAC control module detects the signal circuit is less than 5 Counts (0.09 V) or greater than 250 Counts (4.90 V).
A default value will be used for the sensor data by the HVAC control module. The actual value of the sensor will be displayed on the scan tool.
- The DTC will become history if the HVAC control module no longer detects a condition.
- The history DTC clears after 50 fault free ignition cycles.
- The DTC can be cleared with a scan tool.
If the condition is not present, refer to TESTING FOR INTERMITTENT & POOR CONNECTIONS .
The HVAC control module monitors the ambient light via a sunload sensor. The HVAC control module uses this information in order to modify the effect of the sun on the vehicle inside air temperature. When the sensor is in direct sunlight, the signal voltage is low. When the sensor is covered, the signal voltage is high.
The ignition is turned ON.
The HVAC control module detects the signal circuit is out of the range 0.09-5.0 volts.
A default value will be used for the sensor data by the HVAC control module. The sensor reading, which displays on the scan tool in the HVAC data list, will be this default value.
- The DTC will become history if the HVAC control module no longer detects a condition.
- The history DTC clears after 50 fault free ignition cycles.
- The DTC can be cleared with a scan tool.
If the condition is not present, refer to TESTING FOR INTERMITTENT & POOR CONNECTIONS .
The recirculation actuator is an electronic device that incorporates a stepper motor and feedback potentiometer. The HVAC control module controls the recirculation door position by sending a control signal to the actuator. The signal's value is dependent upon the desired mode selected by the vehicle occupants. As the recirculation actuator moves, the potentiometer produces the actual door position signal that is sent to the HVAC control module. The HVAC control module continues to command the actuator to move until the desired and actual values are equal.
After a calibration or recalibration procedure is performed, the HVAC control module calculates the recirculation actuator travel range. The HVAC control module commands the actuator through it's full range. The HVAC control module stores the learned minimum and maximum position values. The travel range value is calculated by subtracting the minimum and maximum position values. The HVAC control module compares the travel range, minimum and maximum values to calibrated value ranges. If the travel range value is less than or equal to the maximum calibrated limit and greater than or equal to the minimum calibrated limit, then the calibration is considered successful. The HVAC control module continuously compares the actual actuator position to the calibrated minimum and maximum position values.
- The ignition is ON.
- Ignition voltage is between 9-16 volts.
- The HVAC control module keep alive memory battery power must be interrupted to run the range check (recalibration procedure).
- Recirculation actuator position signal is less than 5 counts.
- Recirculation actuator position signal is more than 250 counts.
- The recirculation actuators total travel range (min-max) is less than or greater than the calibrated limits.
- The DTC is stored in DTC information.
- The HVAC control module will continue to make use of whatever travel range is still available.
- If the HVAC control no longer detects a failure, then the DTC will become history.
- The history DTC will clear after 50 ignition cycles without a failure.
- The DTC can be cleared with a scan tool.
- A short to voltage on the 5-volt reference circuit of the recirculation actuator will cause DTC B0229 and DTC B0414 to set.
- A damaged or broken recirculation door and or actuator can cause this DTC to set.
- The range fault can only be detected following a check of the actuator travel range. The actuator travel range check (recalibration procedure) can only be initiated by disrupting power to the HVAC control module.
The mode actuator is an electronic device that incorporates a stepper motor and a feedback potentiometer. The HVAC control module controls the mode door position by sending a control signal to the actuator. The signal's value is dependent upon the desired mode that the vehicle occupants select. While the actuator moves, the potentiometer produces the Actual Door Position signal that is sent to the HVAC control module. The HVAC control module continues to command the actuator to move until the desired value is equal value. The door directs airflow through the outlets which were selected by the vehicle occupants.
- The ignition is ON.
- Ignition voltage is between 9-16 volts.
- A mode actuator change in position is attempted.
The actual mode door position differs from the commanded mode door position by 4 counts or more.
The mode actuator is considered stalled, and the HVAC control module will command the mode actuator to stop rotation (2.5 V).
- If the HVAC control no longer detects a condition, then the DTC will become history.
- The history DTC will clear after 50 ignition cycles without a condition.
- The DTC can be cleared with a scan tool.
- A dead zone exists in a range from 10 counts above the maximum mode door position to 10 counts below the minimum mode door position. When the mode door Actual Data parameter is within the dead zone, the DTC will not set. If the Commanded Data parameter differs from the Actual Data parameter by 4 counts or more outside the dead zone, the DTC will set.
- A damaged mode door, a broken mode door, a damaged actuator, or a broken actuator can cause this DTC to set.
Scheme 153
Scheme 154
The recirculation actuator is an electronic device that incorporates a stepper motor and a feedback potentiometer. The HVAC control module controls the recirculation door position by sending a control signal to the actuator. The signal's value is dependent upon the desired mode that the vehicle occupants select. While the actuator moves, the potentiometer produces the actual door position signal that is sent to the HVAC control module. The HVAC control module continues to command the actuator to move until the desired value is equal to the actual value. The door directs airflow through the outlets which the vehicle occupants selected.
- The ignition is ON.
- Ignition voltage is between 9-16 volts.
- An attempt was made in order to change the position of the recirculation actuator.
The actual recirculation door position differs from the commanded recirculation door position by 4 counts or more.
The recirculation actuator is considered stalled, and the HVAC control module will command the mode actuator to stop rotation (2.5 V).
- If the HVAC control module no longer detects a condition, then the DTC will become history.
- The history DTC will clear after 50 ignition cycles without a condition.
- The DTC can be cleared with a scan tool.
- A dead zone exists in a range from 10 counts above the maximum mode door position to 10 counts below the minimum mode door position. When the mode door Actual Data parameter is within the dead zone, the DTC will not set. If the Commanded Data parameter differs from the Actual Data parameter by 54 counts or more outside the dead zone, the DTC will set.
- A damaged or broken recirculation door or a damaged or broken actuator can cause this DTC to set.
Scheme 155
Scheme 156
The air temperature actuator is an electronic device that incorporates a stepper motor and a feedback potentiometer. The HVAC control module determines the position of the air temperature actuator from the voltage on the potentiometer. When the air temperature changes by greater than 4 counts, the control module performs the following functions
- Drives the air temperature actuator in the appropriate direction in order to achieve the desired setting
- Compares the actual position to the commanded position
If the actual value differs from the commanded value by 4 or more counts, the actuator is stalled, and the DTC will set.
- The ignition is ON.
- Ignition voltage is between 9-16 volts.
- An actuator change in position is attempted.
The actual position of the air mix door differs from the commanded position by at least 4 counts.
The actuator is stalled, and the HVAC control module will command the actuator to stop rotation.
- If the HVAC control no longer detects a condition, then the DTC will become history.
- The history DTC will clear after 50 ignition cycles without a condition.
- The DTC can be cleared with a scan tool.
- A dead zone exists in a range 10 counts above the mix door maximum position to 10 counts below the mix door minimum position. When the air mix door actual data parameter is within the dead zone, the DTC will not set. If the Commanded data parameter differs from the actual data parameter by 4 or more counts outside the dead zone, the DTC will set.
- A damaged air temperature door, a damaged actuator, a broken air temperature door, or a broken actuator can cause this DTC to set.
- If the condition is not present, refer to «TESTING FOR INTERMITTENT & POOR CONNECTIONS»(ref-175672-S23006452642005042500000) .
The air temperature actuator is an electronic device that incorporates a stepper motor and a feedback potentiometer. The HVAC control module determines the position of the air temperature actuator that is based on the voltage from the potentiometer. When the keep alive RAM memory, the battery positive voltage circuit, of the HVAC control module is interrupted, the module will calibrate the actuators. The HVAC control module performs a travel range comparison of the determined values of the actuator to the calibrated values within the HVAC control module. If the determined range does not equal the calibrated expected range, the actuator will be considered not calibrated, and the DTC will set. The HVAC control module will also perform a continuous test on the current feedback value. If the feedback value does not fall within the calibrated range, the DTC will set.
- The ignition is ON.
- Ignition voltage is between 9-16 volts.
- The battery positive voltage circuit, which provides keep alive RAM memory power, of the HVAC control module must be interrupted in order to run the recalibration. This includes disconnecting the battery, removal of the Radio fuse and disconnecting the HVAC control module.
- The position signal of the air temperature door is out of the range 0.09-4.0 volts (5-250 counts).
- The total travel range of the air temperature actuator falls without the calibrated limits.
- The HVAC control module will continue to make use of whatever travel range is still available.
- Each time the ignition switch is turned ON, the HVAC control module retests the actuator travel range.
- If the HVAC control module no longer detects a condition, then the DTC will become history.
- The history DTC will clear after 50 ignition cycles without a condition.
- The DTC can be cleared with a scan tool.
- The range fault can only be detected following a recalibration. The recalibration can only be initiated by removing the battery positive voltage circuit to the HVAC control module.
- The calibration limit is 64-216 counts. An actual range below this limit suggests an obstruction, something stuck in the door which limits travel. An actual range above this limit suggests an excessive travel condition, damaged, or missing foam seals.
- A damaged air temperature door or a damaged actuator can cause this DTC to set.
- An intermittent short to ground on the HVAC class 2 serial data circuit can set this DTC. Recalibrate actuators and test system.
- If the conditions is not present, refer to «TESTING FOR INTERMITTENT & POOR CONNECTIONS»(ref-175672-S23006452642005042500000) .
The mode actuator is an electronic device that incorporates a stepper motor and a feedback potentiometer. The HVAC control module determines the position of the mode actuator that is based on the voltage from the potentiometer. When the keep alive RAM memory, the battery positive voltage circuit, of the HVAC control module is interrupted, the module will calibrate the actuators. The HVAC control module performs a travel range comparison of the determined values of the actuator to the calibrated values within the HVAC control module. If the determined range does not equal the calibrated expected range, the actuator will be considered not calibrated, and the DTC will set. The HVAC control module will also perform a continuous test on the current feedback value. If the feedback value does not fall within the calibrated range, the DTC will set.
- The ignition is ON.
- Ignition voltage is between 9-16 volts.
- The battery positive voltage circuit, which provides keep alive RAM memory power, of the HVAC control module must be interrupted in order to run the recalibration. This includes disconnecting the battery, removal of the Radio fuse and disconnecting the HVAC control module.
- The position signal of the mode door is out of the range 0.09-4.0 volts (5-250 counts).
- The total travel range of the mode actuator falls without the calibrated limits.
- The HVAC control module will continue to make use of whatever travel range is still available.
- Each time the ignition switch is turned ON, the HVAC control module retests the actuator travel range.
- If the HVAC control no longer detects a condition, then the DTC will become history.
- The history DTC will clear after 50 ignition cycles without a condition.
- The DTC can be cleared with a scan tool.
- The range fault can only be detected following a recalibration. The recalibration can only be initiated by removing the battery positive voltage circuit to the HVAC control module.
- The calibration limit is 64-216 counts. An actual range below this limit suggests an obstruction, something stuck in the door which limits travel. An actual range above this limit suggests an excessive travel condition, damaged, or missing foam seals.
- A damaged mode door or a damaged actuator can cause this DTC to set.
- An intermittent short to ground on the HVAC class 2 serial data circuit can set this DTC. Recalibrate actuators and test system.
- If the condition is not present, refer to «TESTING FOR INTERMITTENT & POOR CONNECTIONS»(ref-175672-S23006452642005042500000) .
Scheme 157
Scheme 158
Scheme 159
Important: Complete the following steps before using the symptom tables
- Perform «Diagnostic System Check - HVAC Systems - Automatic»(ref-175920-S01778674802005042800000) before using the Symptom Tables in order to verify that all of the following conditions are true: 1.1 No DTCs are set. 1.2 The control modules can communicate via the serial data link.
- Review the system operation in order to become familiar with the system functions. Refer to the following procedures: See «Air Delivery Description & Operation»(ref-175920-S30187164942005042800000) . See «Air Temperature Description & Operation»(ref-175920-S19276166432005042800000) .
Visual/Physical Inspection
- Inspect for aftermarket devices which can affect the operation of the HVAC System. Refer to «CHECKING AFTERMARKET ACCESSORIES»(ref-175672-S27030348872005042500000) .
- Inspect the accessible and the visible system components for obvious damage or for conditions which can cause the symptom.
- Verify the A/C compressor clutch turns freely and is not seized.
- Verify that the customer is using the correct key in order to enable personalization and is not activating the auxiliary HVAC controls.
- The A/C compressor will not operate in cold ambient air temperatures. Refer to «Air Temperature Description & Operation»(ref-175920-S19276166432005042800000) .
- The following conditions may cause window fogging: A wet carpet or wet floor mats High humidity An interior water leak A blocked A/C evaporator drain tube Maximum passenger capacity Blocked body pressure relief valves
- Inspect the air distribution system for causes of reduced airflow: An obstructed or dirty passenger compartment air filter, if equipped Blocked or damaged air vents
Symptom List
Refer to the following diagnostic procedures
- See «HVAC Compressor Clutch Does Not Engage»(ref-175920-S20048882402005042800000) .
- See «HVAC Compressor Clutch Does Not Disengage»(ref-175920-S35705038712005042800000) .
- See «Blower Motor Always On»(ref-175920-S38931987572005042800000) .
- See «Blower Motor Inoperative»(ref-175920-S01091735792005042800000) .
- See «Blower Motor Malfunction»(ref-175920-S23062935552005042800000) .
- See «Too Hot In Vehicle»(ref-175920-S02237649342005042800000) .
- See «Too Cold In Vehicle»(ref-175920-S12547369632005042800000) .
- See «Outside Air Temperature Display Inaccurate Or Inoperative»(ref-175920-S18822423792005042800000) .
- See «Air Delivery Improper»(ref-175920-S40088890682005042800000) .
- See «Air Recirculation Malfunction»(ref-175920-S14089954072005042800000) .
- See «LEAK TESTING»(ref-175819-S39168181322005042700000) .
- See «DEFROSTING INSUFFICIENT»(ref-175819-S10456538332005042700000) .
- See «HIGH OR LOW TEMPERATURE CONTROL EFFORT»(ref-175819-S40954992892005042700000) .
- See «NOISE DIAGNOSIS - BLOWER MOTOR»(ref-175819-S00483955442005042700000) .
- «NOISE DIAGNOSIS - A/C SYSTEM»(ref-175819-S34444523452005042700000) .
- See «ODOR DIAGNOSIS»(ref-175819-S19320770382005042700000) .