GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Corvette 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 DTC B0441 or B0446

Circuit Description

The following DTCs are for the left and right air temperature actuators:

    • B0441 is for the left air temperature actuator
    • B0446 is for the right air temperature actuator

The HVAC control module commands the air temperature actuators to move by controlling the voltage supplied on the control circuit. A signal voltage of 0 volts or a signal voltage of 5 volts rotates the air temperature actuator. A voltage of 2.5 volts stops the door. The HVAC control module determines the current position of the actuator by monitoring the feedback voltage of the air temperature door position signal circuit. The feedback potentiometer position is a function of the air temperature actuator. The HVAC control module controls the air temperature door position in order to maintain the selected air temperature.

Whenever the HVAC control module keep alive memory battery power is interrupted, the HVAC control module will perform a recalibration of the actuators. During recalibration, the HVAC control module will drive the air temperature actuators to their minimum and maximum travel extremes. The HVAC control module will then calculate a travel range from this data and compare it to a calibrated range within the HVAC control module. If the actual travel range is not within the calibrated expected range, the actuator will be considered not calibrated and the DTC will set.

Conditions for Running the DTC
    • The ignition is turned ON.
    • The HVAC control module power must be interrupted.

Conditions for Setting the DTC

The air temperature actuator actual total travel range is less than or more than the calibrated limits.

Action Taken When the DTC Sets
    • The HVAC control module will continue to make use of whatever air temperature actuator travel range is still available.
    • Each time the ignition switch is turned ON the HVAC control module will perform a recalibration of the actuator.

Conditions for Clearing the DTC

The air temperature actuator travel range error must be corrected.

Diagnostic Aids
    • The range fault code can only be detected following a check of the air temperature actuator travel range. The air temperature actuator travel range check can only be initiated by disrupting power to the HVAC control module or with the scan tool.
    • The calibration limit is 147-220 counts (2.9-4.4 V). An actual range below this limit suggests an obstruction, something stuck in the door limiting travel. An actual range above this limit suggests an over travel condition, damaged or missing foam seals.
    • If condition not present, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Step

Action

Values

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

1

Did you perform the HVAC Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Automatic

2
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the appropriate Mix Motor ON and OFF to display the maximum and the minimum counts of the appropriate Mix Motor Position Feedback in the Heating and Air Conditioning, Special Functions, Miscellaneous Test list.
  4. Subtract the minimum appropriate Mix Motor Position Feedback from the maximum appropriate Mix Motor Position Feedback.

Does the result of the calculation indicate that the actual travel of the appropriate air temperature actuator is within the specified range?

147-220 counts

Go to Diagnostic Aids

Go to Step 3

3

Test the ignition 3 voltage circuit of the appropriate air temperature actuator for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 4

4

Test the air temperature door control circuit of the appropriate air temperature actuator for an open, high resistance, short to ground or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 5

5

Test the 5 volt reference circuit of the appropriate air temperature actuator for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 6

6

Important: The appropriate air temperature actuator connector and the HVAC control module connector must be connected to correctly perform test.

  1. Turn ON the ignition, with the engine OFF.
  2. With the scan tool, observe the appropriate Mix Motor Position Feedback data parameter.
  3. Connect a 3 amp fused jumper wire between the air temperature door control circuit and the 5 volt reference circuit of the appropriate air temperature actuator. This action drives the actuator to the full HOT position, for the left air temperature actuator, or full COLD for the right air temperature actuator.
  4. Remove and reconnect the jumper wire between the air temperature door control circuit and the low reference circuit of the appropriate air temperature actuator. This action drives the actuator to the full COLD position, for the left air temperature actuator, or full HOT for the right air temperature actuator.

Does the appropriate air temperature actuator drive shaft rotate and do the counts change?

--

Go to Step 7

Go to Step 9

7
  1. Measure the voltage from the temperature door control circuit of the appropriate air temperature actuator to a good ground.
  2. With a scan tool, command the appropriate Temp Door Position from Hot to Cold.

Does the voltage measure near the specified value when increasing temperature, near the specified value when decreasing temperature and near the specified value when stationary?

0 V decreasing 5 V increasing 2.5 V stationary

Go to Step 8

Go to Step 10

8

Inspect the appropriate air temperature door and the appropriate air temperature actuator for the following conditions:

    • A misaligned air temperature actuator
    • A broken or binding linkages or air temperature door
    • An obstruction that prevents the air temperature door from operating within its full range of motion
    • Missing seals to the air temperature door
    • Misaligned seals to the air temperature door

Did you find and correct the condition?

--

Go to Step 13

Go to Diagnostic Aids

9

Inspect for poor connections at the harness connector of the appropriate air temperature actuator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 11

10

Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

11

Important: Perform the recalibration procedure for the appropriate air temperature actuator.

Replace the appropriate air temperature actuator. Refer to Air Temperature Actuator Replacement - Left Side or Air Temperature Actuator Replacement - Right Side .

Did you complete the replacement?

--

Go to Step 13

--

12

Important : Perform the recalibration procedure for the HVAC control module.

Replace the HVAC control module. Refer to HVAC Control Module Replacement .

Did you complete the replacement?

--

Go to Step 13

--

13
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK