GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2002 🢒 Bonneville 🢒 DTC 🢒 DTC B0233

Circuit Description

The air temperature actuator is an electronic stepper motor without a feedback circuit. It responds to voltage inputs from the HVAC control module with precalibrated, non-adjustable position settings. Zero volts drives the actuator in one direction while 12 volts drives it in the opposite direction. The HVAC control module adjusts the air temperature actuator position to maintain the air temperature selected by the vehicle occupants.

Conditions for Running the DTC
    • The ignition is turned ON.
    •  DTC B1327 must not be current.

Conditions for Setting the DTC

The air temperature door control circuit is shorted to ground or shorted to battery voltage for more than 2 seconds.

Action Taken When the DTC Sets

Control of the air temperature door position will be disabled.

Conditions for Clearing the DTC
    • The DTC will become history if the HVAC control module no longer detects a failure.
    • The history DTC clears after 50 fault-free ignition cycles.
    • Use the scan tool in order to clear the DTCs.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. The air temperature actuator can be driven to one of two positions using the Cold and Hot command keys on the scan tool. The scan tool displays module output as a percentage of maximum control voltage. It does not indicate true actuator or door position.

  2. This step verifies that the air temperature actuator is receiving the control voltage.

Step

Action

Yes

No

Schematic Reference: HVAC Schematics

1

Did you perform the HVAC Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Manual

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the air temperature actuator to HOT and to COLD.
  4. Observe the air temperature actuator.

Does the drive shaft of the air temperature actuator rotate?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the air temperature actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the air temperature door control circuit of the air temperature actuator to a good ground.
  5. With a scan tool, command the air temperature actuator to HOT and to COLD.

Does the voltage change?

Go to Step 5

Go to Step 4

4

Test the air temperature door control circuit of the air temperature actuator for a short to ground and a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 6

5

Inspect for poor connections at the harness connector of the 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 9

Go to Step 7

6

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 9

Go to Step 8

7

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

Replace the air temperature actuator. Refer to Air Temperature Actuator Replacement .

Did you complete the replacement?

Go to Step 9

--

8

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

Did you complete the replacement?

Go to Step 9

--

9
  1. Use a 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