GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

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

DTC Descriptors

DTC B0223 04: Recirculate Position Command Circuit Open

DTC B0223 05: Recirculate Position Command Circuit Short to Battery or Open

DTC B0223 06: Recirculate Position Command Circuit Short to Ground or Open

DTC B0223 61: Recirculation Actuator Stuck

DTC B0233 04: Air Flow Control Circuit Open

DTC B0233 05: Air Flow Control Circuit Short to Battery or Open

DTC B0233 06: Air Flow Control Circuit Short to Ground or Open

DTC B0233 61: Air Flow Control Actuator Stuck

DTC B0408 04: Temperature Control 1 Circuit Open

DTC B0408 05: Temperature Control 1 Circuit Short to Battery or Open

DTC B0408 06: Temperature Control 1 Circuit Short to Ground or Open

DTC B0408 61: Temperature Control 1 Circuit Actuator Stuck

DTC B0418 04: Temperature Control 2 Circuit Open

DTC B0418 05: Temperature Control 2 Circuit Short to Battery or Open

DTC B0418 06: Temperature Control 2 Circuit Short to Ground or Open

DTC B0418 61: Temperature Control 2 Circuit Actuator Stuck

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Recirculate Position Command Circuit A

B0223 04, 06

B0223 04, 06

B0223 05, 06

B0223 61

Recirculate Position Command Circuit B

B0223 04, 06

B0223 04, 06

B0223 05, 06

B0223 61

Mode Door Control Circuit A

B0233 04, 06

B0233 04, 06

B0233 05, 06

B0233 61

Mode Door Control Circuit B

B0233 04, 06

B0233 04, 06

B0233 05, 06

B0233 61

Driver Air Temperature Door Control A Circuit

B0408 04, 06

B0408 04, 06

B0408 05, 06

B0408 61

Driver Air Temperature Door Control B Circuit

B0408 04, 06

B0408 04, 06

B0408 05, 06

B0408 61

Passenger Air Temperature Door Control A Circuit

B0418 04, 06

B0418 04, 06

B0418 05, 06

B0418 61

Passenger Air Temperature Door Control B Circuit

B0418 04, 06

B0418 04, 06

B0418 05, 06

B0418 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 2 driver circuits. The HVAC control module supplies the actuator motor with a 12-volt driver control circuit and a ground driver 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 4 counts or the HVAC control module detects the door position signal circuit is shorted to ground shorted to voltage or open.

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 Output Controls
    •  Scan Tool Data List

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector of the appropriate actuator.
  2. Ignition ON, command the actuator ON.
  3. Verify that a test lamp does not illuminate between battery voltage and control circuits A and B.
  4. If the test lamp stays illuminated, test the control A or control B circuit for a short to ground. If circuit tests normal replace the HVAC control module.
  5. Command the actuator OFF.
  6. Verify that a test lamp illuminates between battery voltage and control circuits A and B.
  7. If the test lamp does not stay illuminated, test the control A or control B circuit for a short to voltage or an open/high resistance. If circuit tests normal replace the HVAC control module.
  8. Command the actuator ON.
  9. Verify that a test lamp illuminates between ground and control circuits A and B.
  10. If the test lamp does not stay illuminated, test the control A or control B circuit for a short to ground or an open/high resistance. If circuit tests normal replace the HVAC control module.
  11. Command the actuator OFF.
  12. Verify that a test lamp does not illuminate between ground and control circuits A and B.
  13. If the test lamp stays illuminated, test the control A or control B circuit for a short to voltage. If circuit tests normal replace the HVAC control module.
  14. If all circuits test normal, replace the actuator.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  HVAC Control Module Programming and Setup
    •  Recirculation Actuator Replacement
    •  Mode Actuator Replacement
    •  Temperature Valve Actuator Replacement - Left Side
    •  Temperature Valve Actuator Replacement - Right Side