For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Strategy Based Diagnosis

• | Diagnostic Procedure Instructions

### DTC Descriptors

DTC B0228 02 : Recirculate Position Feedback Circuit Short to Ground
DTC B0228 04 : Recirculate Position Feedback Circuit Open
DTC B0228 05 : Recirculate Position Feedback Circuit Short to Battery
DTC B0228 61 : Recirculate Position Feedback Circuit Actuator Stuck
DTC B0413 02 : Temperature Control 1 Circuit Short to Ground
DTC B0413 04 : Temperature Control 1 Feedback Circuit Open Circuit
DTC B0413 05 : Temperature Control 1 Feedback Circuit Short to Battery or Open
DTC B0413 08 : Temperature Control 1 Circuit Actuator Signal Invalid
DTC B0413 61 : Temperature Control 1 Feedback Circuit Actuator Stuck
DTC B0423 02 : Temperature Control 2 Circuit Short to Ground
DTC B0423 04 : Temperature Control 2 Feedback Circuit Open Circuit
DTC B0423 05 : Temperature Control 2 Feedback Circuit Short to Battery or Open
DTC B0423 61 : Temperature Control 2 Feedback Circuit Actuator Stuck
DTC B0433 02 : Temperature Control 3 Circuit Short to Ground
DTC B0433 04: Temperature Control 3 Feedback Circuit Open Circuit
DTC B0433 05 : Temperature Control 3 Feedback Circuit Short to Battery or Open
DTC B0433 61 : Temperature Control 3 Feedback Circuit Actuator Stuck
DTC B3779 02 : Air Flow Control 9 Feedback Circuit Short to Ground
DTC B3779 04 : Air Flow Control 9 Feedback Circuit Open Circuit
DTC B3779 05 : Air Flow Control 9 Feedback Circuit Short to Battery or Open
DTC B3779 61 : Air Flow Control 9 Feedback Circuit Actuator Stuck
DTC B3782 02 : Air Flow Control 10 Feedback Circuit Short to Ground
DTC B3782 04 : Air Flow Control 10 Feedback Circuit Open Circuit
DTC B3782 05 : Air Flow Control 10 Feedback Circuit Short to Battery or Open
DTC B3782 61 : Air Flow Control 10 Feedback Circuit Actuator Stuck

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Recirculation Door Control A Circuit | B0228 61 | B0228 61 | -- | --
Recirculation Door Control B Circuit | B0228 61 | B0228 61 | -- | --
Recirculation Door Position Signal | B0228 61 | B0228 02 B0228 04 | B0228 61 B0228 02 B0228 04 | --
Recirculation 5-Volt Reference Circuit | B0433 61 B0423 61 B0228 61 B3782 61 | B0228 02 B0228 04 | B0228 61 B0228 02 B0228 04 | --
Recirculation Low Reference Circuit | -- | B0228 61 | -- | --
Driver Air Temperature Door Control A Circuit | B0423 61 | B0423 61 | -- | --
Driver Air Temperature Door Control B Circuit | B0423 61 | B0423 61 | -- | --
Driver Air Temperature Door Position Signal | B0423 61 | B0413 06 | B0423 61 B0423 02 B0423 04 | --
Driver Air Temperature 5-Volt Reference Circuit | B0433 61 B0423 61 B0228 61 B3782 61B3779 61 | B0423 02 B0423 04 | B0423 02 B0423 04 | --
Driver Air Temperature Low Reference Circuit | -- |  | -- | --
Passenger Air Temperature Door Control A Circuit | B0423 61 | B0423 61 | -- | --
Passenger Air Temperature Door Control B Circuit | B0423 61 | B0423 61 | -- | --
Passenger Air Temperature Door Position Signal | B0423 61 | B0228 61 B0423 02 B0423 04 | B0423 61 | --
Passenger Air Temperature 5-Volt Reference Circuit | B0433 61 B0423 61 B0228 61 B3782 61 B3779 61 | B0423 61 | B0228 61 B0423 02 B0423 04 | --
Passenger Air Temperature Low Reference Circuit | -- | B0423 61 | -- | --
Mode Door Control A Circuit | B0433 61 | B0433 61 | -- | --
Mode Door Control B Circuit | B0433 61 | B0433 61 | -- | --
Mode Door Position Signal | B0433 61 | B0433 61 B3782 02 B3782 04 B3779 02 B3779 04 | B0433 61 B3782 02 B3782 04 B3779 02 B3779 04 | --
Mode 5-Volt Reference Circuit | B0433 61 B0423 61 B0228 61 B3782 61B3779 61 | B0433 61 | B0433 61 B3782 02 B3782 04 B3779 02 B3779 04 | --
Mode Low Reference Circuit | -- | B0433 61 | -- | --
Auxiliary Air Temperature Door Control A Circuit | B0433 61 | B0433 61 | -- | --
Auxiliary Air Temperature Door Control B Circuit | B0433 61 | B0433 61 | -- | --
Auxiliary Air Temperature Door Position Signal | B0433 61 | B0433 61 B0433 02 B0433 04 | B0433 61 B0433 02 B0433 04 | --
Auxiliary Air Temperature 5-Volt Reference Circuit | B0433 61 B0423 61 B0228 61 B3782 61B3779 61 | B0433 61 | B0428 61 B0433 02 B0433 04 | --
Auxiliary Air Temperature Low Reference Circuit | -- | B0433 61 | -- | --
Auxiliary Mode Door Control A Circuit | B3782 61B3779 61 | B3782 61 B3779 61 | -- | --
Auxiliary Mode Door Control B Circuit | B3782 61B3779 61 | B3782 61 B3779 61 | -- | --
Auxiliary Mode Door Position Signal | B3782 61B3779 61 | B3782 61 B3779 61 | B3782 61 B3779 61 | --
Auxiliary Mode 5-Volt Reference Circuit | B0433 61 B0423 61 B0228 61 B3782 61B3779 61 | B3782 61 B3779 61 | B3782 61 B3779 61 | --
Auxiliary Mode Low Reference Circuit | -- | B3782 61 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 HVAC control module supplies the actuator motor with a12-volt control circuit and a ground control circuit. The HVAC module controls the direction of the actuator door by changing the polarity of the control circuits.

### 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 5 counts or the HVAC control module detects the door position signal circuit is less than 12 counts or greater than 247 counts.

### Action Taken When the DTC Sets

Driver A and driver B circuits are 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.

### Reference Information

#### Schematic Reference

HVAC Schematics

#### Connector End View Reference

HVAC Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

• | Scan Tool Data List

• | Scan Tool Output Controls

• | Scan Tool Data Definitions

### Circuit/System Verification

Ignition ON, operate the appropriate actuator using the HVAC controls. The applicable scan tool parameter should transition from 7 counts to 250 counts.

### Circuit/System Testing

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

⇒ | If greater than 1 ohm, test the low reference circuit terminal 1 for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.

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

⇒ | If less than 4.8 volts, test the 5-volt reference circuit terminal 3 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 terminal 3 for a short to voltage. If the circuit tests normal, replace the HVAC control module.

4. Verify the appropriate scan tool parameter is less than 5 counts.

⇒ | If greater than 5 counts, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the HVAC Control Module.

5. Install a 3-amp fused jumper wire between the signal circuit terminal 3 and the low reference circuit terminal 1. 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. If the circuit tests normal, replace the HVAC control module.

6. Connect a test lamp between the control circuits terminal 4 and 5 of the applicable actuator.
7. Command the actuator in both directions with a scan tool. The test lamp should turn ON and OFF with each command.

⇒ | If the test lamp remains always ON or always OFF during either of the commands, test both control circuits for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal replace the HVAC control module.

8. Ignition ON, after 30 seconds verify that a test lamp illuminates between control circuit B terminal and B+.

⇒ | If the test lamp does not illuminate, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal replace the HVAC control module.

9. Ignition OFF, verify that the test lamp does not illuminate between control circuit B terminal and B+.

⇒ | If the test lamp illuminates, test the control circuit for a short to ground. If circuit tests normal replace the HVAC control module.

10. If all circuits test normal, test or replace the appropriate actuator.

### Repair Instructions

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Control Module References for HVAC replacement, setup, and programming.

• | Recirculation Actuator Replacement

• | Mode Actuator Replacement

• | Temperature Valve Actuator Replacement

• | Auxiliary Temperature Valve Actuator Replacement

• | Auxiliary Mode Valve Actuator Replacement