B0433

DTC B0228, B0413, B0423, B0433, B3779 or B3782

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0228 02
- Recirculate Position Feedback Circuit Short to Ground

DTC B0228 05
- Recirculate Position Feedback Circuit Short to Battery or Open

DTC B0228 61
- Recirculate Position Circuit Actuator Stuck

DTC B0413 02
- Temperature Control 1 Feedback Circuit Short to Ground

DTC B0413 05
- Temperature Control 1 Feedback Circuit Short to Battery or Open

DTC B0413 61
- Temperature Control 1 Feedback Circuit Actuator Stuck Open

DTC B0423 02
- Temperature Control 2 Feedback Circuit Short to Ground

DTC B0423 05
- Temperature Control 2 Feedback Circuit Short to Battery or Open

DTC B0423 61
- Temperature Control 2 Circuit Actuator Stuck

DTC B0433 02
- Temperature Control 3 Feedback Circuit Short to Ground

DTC B0433 05
- Temperature Control 3 Feedback Circuit Short to Battery or Open

DTC B0433 61
- Temperature Control 3 Circuit Actuator Stuck

DTC B3782 02
- Air Flow Control 10 Feedback Circuit Short to Ground

DTC B3782 05
- Air Flow Control 10 Feedback Circuit Short to Battery or Open

DTC B3782 61
- Air Flow Control 10 Circuit Actuator Stuck

DTC B3779 02
- Air Flow Control 9 Feedback Circuit Short to Ground

DTC B3779 05
- Air Flow Control 9 Feedback Circuit Short to Battery or Open

DTC B3779 61
- Air Flow Control 9 Circuit Actuator Stuck

Diagnostic Fault Information










Circuit/System Description

The HVAC control module controls the HVAC door actuators to regulate the airflow through the HVAC system. Each actuator consists of an electric motor and a potentiometer. The module supplies a low reference and 5-volt reference source voltage to the potentiometer. The HVAC control module monitors the voltage drop across the potentiometer on the door position signal circuit. When the actuator shaft rotates, the voltage on the door position signal circuit changes. The control circuit uses either a 0, 2.5 or 5-volt signal to command the actuator movement. When the actuator is at rest, the control circuit value is 2.5 volts. A 0 or 5-volt control signal commands the actuator movement in opposite directions.

* DTC B0228 is for the recirculate actuator
* DTC B0413 is for the drivers air temperature actuator
* DTC B0423 is for the passenger air temperature actuator
* DTC B0433 is for the auxiliary air temperature actuator
* DTC B3782 is for the auxiliary mode actuator
* DTC B3779 is for the mode actuator

Conditions for Running the DTC

* The ignition is ON.
* Ignition voltage is between 9-16 volts.
* The HVAC module is ON.

Conditions for Setting the DTC

The actual door position differs from the commanded door position by more than 4 counts or the HVAC control module detects the door position signal circuit is less than 7 counts or greater than 250 counts.

Action Taken When the DTC Sets

The control circuit is deactivated for the appropriate actuator.

Conditions for Clearing the DTC

* The DTC becomes history when the HVAC control module no longer detects the condition that set the DTC.
* The history DTC will clear after 50 fault-free ignition cycles.
* The DTC can be cleared with a scan tool.

Circuit/System Testing

1. Ignition OFF, disconnect the appropriate actuator and test for less than 1 ohm of resistance between the low reference circuit and ground.

• If greater than 1 ohm, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.

2. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit and ground.

• If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
• If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the HVAC control module.

3. Verify the appropriate scan tool parameter is less than 4 counts.

• If greater than 4 counts, test the signal circuit for a short to ground. If the circuit tests normal, replace the HVAC Control Module.

4. Install a 3-amp fused jumper wire between the signal circuit and the low reference circuit terminal. Verify the appropriate scan tool parameter is greater than 250 counts.

• If less than 250 counts, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.

5. Ignition ON, verify that a test lamp illuminates between the ignition 3 circuit and ground.

• If the test lamp does not illuminate, test the ignition 3 circuit for a short to ground an open/high resistance.

6. Install a DMM between the actuator control circuit and ground. While monitoring the DMM use the scan tool to command the appropriate actuator from one direction to the other. If the voltage on the control circuit moves from 0 volt in one direction to 5 volts in the other direction and 2.5 volts in the at rest state.

• If the voltage does not change, test the control circuit for an open, short to voltage or short to ground. If circuit tests normal replace the HVAC control module.

7. If all circuits test normal, replace the actuator.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

* Refer to Programming and Relearning for HVAC control module and HVAC Auxiliary control module or rear seat audio (RSA) replacement, setup, and programming.
* Recirculation Actuator Replacement
* Mode Actuator Replacement
* Air Temperature Actuator Replacement - Left Side
* Air Temperature Actuator Replacement - Right Side
* Auxiliary Air Temperature Actuator Replacement
* Auxiliary Mode Actuator Replacement Verification Tests