Diagnostic Instructions

DTC Descriptor

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 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	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Recirculation Door Ignition	B0228 02	B0228 05	B0228 05	B0228 61
Recirculation 5-Volt Reference	B0228 02, B0413 02, B0423 02 or B3779 02	B0228 05	B0228 02, B0413 02, B0423 02 or B3779 02	B0228 61
Recirculation Door Position Signal	B0228 02	B0228 05	B0228 05	B0228 61
Recirculation Door Control	B0228 02	B0228 05	B0228 05	B0228 61
Recirculation Low Reference	B0228 02	B0228 05	B0228 05	B0228 61
Driver Air Temperature Door Ignition	B0413 02	B0413 05	B0413 05	B0413 61
Driver Air Temperature 5-Volt Reference	B0228 02, B0413 02, B0423 02 or B3779 02	B0413 05	B0228 02, B0413 02, B0423 02 or B3779 02	B0413 61
Driver Air Temperature Door Position Signal	B0413 02	B0413 05	B0413 05	B0413 61
Driver Air Temperature Door Control	B0413 02	B0413 05	B0413 05	B0413 61
Driver Air Temperature Low Reference	B0413 02	B0413 05	B0413 05	B0413 61
Passenger Air Temperature Door Ignition	B0423 02	B0423 05	B0423 05	B0423 61
Passenger Air Temperature 5-Volt Reference	B0228 02, B0413 02, B0423 02 or B3779 02	B0423 05	B0228 02, B0413 02, B0423 02 or B3779 02	B0423 61
Passenger Air Temperature Door Position Signal	B0423 02	B0423 05	B0423 05	B0423 61
Passenger Air Temperature Door Control	B0423 02	B0423 05	B0423 05	B0423 61
Passenger Air Temperature Low Reference	B0423 02	B0423 05	B0423 05	B0423 61
Mode Door Ignition	B3779 02	B3779 05	B3779 05	B3779 61
Mode 5-Volt Reference	B0228 02, B0413 02, B0423 02 or B3779 02	B3779 05	B0228 02, B0413 02, B0423 02 or B3779 02	B3779 61
Mode Door Position Signal	B3779 02	B3779 05	B3779 05	B3779 61
Mode Door Control	B3779 02	B3779 05	B3779 05	B3779 61
Mode Low Reference	B3779 02	B3779 05	B3779 05	B3779 61

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.

Conditions for Running the DTC

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 3 counts or greater than 253 counts.

Action Taken When the DTC Sets

The control circuit is deactivated for the appropriate actuator.

Conditions for Clearing the DTC

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Verification

Ignition ON, command the appropriate actuator in both directions with a scan tool. The scan tool door position parameter reading should be between 3 and 253 counts.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate actuator.
2. Test for less than 1 ohm between the low reference circuit terminal 7 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance.

3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 10 and ground.

⇒	If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance.

⇒	If greater than the specified range, test the 5-volt reference circuit for a short to voltage.

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

⇒	If greater than the specified range, test the signal circuit terminal 9 for a short to ground.

5. Install a 3-amp fused jumper wire between the signal circuit terminal 9 and the low reference circuit terminal. Verify the appropriate scan tool parameter is greater than 250 counts.

⇒	If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance.

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

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

7. Install a DMM between the actuator control circuit terminal 6 and ground. While monitoring the DMM, use the scan tool to command the appropriate actuator from one direction to the other. The voltage on the control circuit should move from 0 volts 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.

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

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.