B0423
DTC B0228, B0413, B0423, B0433, B3779, or B3782
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
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 or Open
DTC B0228 08
- Recirculate Position Circuit Actuator Stalled
DTC B0228 61
- Recirculate Position Circuit Actuator Stuck
DTC B0413 02
- Temperature Control 1 Feedback Circuit Short to Ground
DTC B0413 04
- Temperature Control 1 Feedback Circuit Open
DTC B0413 05
- Temperature Control 1 Feedback Circuit Short to Battery or Open
DTC B0413 08
- Temperature Control 1 Feedback Circuit Actuator Stalled
DTC B0413 61
- Temperature Control 1 Feedback Circuit Actuator Stuck Open
DTC B0423 02
- Temperature Control 2 Feedback Circuit Short to Ground
DTC B0423 04
- Temperature Control 2 Feedback Circuit Open
DTC B0423 05
- Temperature Control 2 Feedback Circuit Short to Battery or Open
DTC B0423 08
- Temperature Control 2 Circuit Actuator Stalled
DTC B0423 61
- Temperature Control 2 Circuit Actuator Stuck
DTC B0433 02
- Temperature Control 3 Feedback Circuit Short to Ground
DTC B0433 04
- Temperature Control 3 Feedback Circuit Open
DTC B0433 05
- Temperature Control 3 Feedback Circuit Short to Battery or Open
DTC B0433 08
- Temperature Control 3 Circuit Actuator stalled
DTC B0433 61
- Temperature Control 3 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
DTC B3779 05
- Air Flow Control 9 Feedback Circuit Short to Battery or Open
DTC B3779 08
- Air Flow Control 9 Circuit Actuator stalled
DTC B3779 61
- Air Flow Control 9 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
DTC B3782 05
- Air Flow Control 10 Feedback Circuit Short to Battery or Open
DTC B3782 08
- Air Flow Control 10 Circuit Actuator Stalled
DTC B3782 61
- Air Flow Control 10 Circuit Actuator Stuck
Circuit/System Description
The actuators operate using 5 circuits. A 5-volt reference, low reference, signal circuit and two bi-directional 0 or 12 volt control circuits. The HVAC control module supplies a low reference and 5-volt reference to the potentiometer. The HVAC control module monitors the voltage drop across the potentiometer on the door position signal circuit. As the actuator door changes position the door position signal circuit voltage also changes. The two bi-directional control circuits enable the actuator to operate. Both circuits are set to 0 volts when the HVAC control module detects, from the feedback potentiometer, that the actuator is in the desired position. In order to move the actuator, the HVAC control module switches the appropriate control circuit to 12 volts.
* DTC B0228 is for the recirculate actuator
* DTC B0413 is for the left air temperature actuator
* DTC B0423 is for the right 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.
* 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 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
* The DTC becomes history when the HVAC control module no longer detects the condition that set the DTC.
* The history DTC will clear after 100 fault-free ignition cycles.
Reference Information
Schematic Reference
HVAC Schematics HVAC - Automatic
Connector End View Reference
Component Connector End Views A/C Compressor Clutch
Description and Operation
* Air Delivery Description and Operation Air Delivery
* Air Temperature Description and Operation Air Temperature
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References 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 all external devices to include the scan tool and battery charger. It will take more than 10 minutes for all vehicle systems to power down.
2. Disconnect the harness connector at the appropriate actuator.
3. Test for less than 10 ohms between the low reference circuit terminal 8 and ground.
Note: Ground measurements will be abnormally high if taken before all vehicle systems have powered down.
• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
4. 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 the circuit tests normal, replace the HVAC control module.
• If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the HVAC control module.
5. Verify the scan tool Door Position parameter is greater than 250 counts.
• If less than the specified range, test the signal circuit terminal 9 for a short to ground. If the circuit tests normal, replace the HVAC control module.
6. Install a 3A fused jumper wire between the signal circuit terminal 9 and the low reference circuit terminal 8. Verify the scan tool Door Position parameter is less than 3 counts.
• If greater 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.
7. Ignition ON, test for less than 10 ohms between the control circuit terminal 5 and ground.
• If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal, replace the HVAC control module.
8. Ignition ON, test for less than 10 ohms between the control circuit terminal 6 and ground.
• If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal, replace the HVAC control module.
9. Connect a test lamp between control circuit terminal 5 and control circuit terminal 6.
10. Ignition ON, command the appropriate actuator door in both directions with a scan tool. The test lamp should turn ON and OFF when commanded in both directions.
• If the test lamp remains OFF during either of the commands, test for a short to ground on either control circuit. If the circuits test normal, replace the HVAC control module.
11. If both circuits test normal, test or replace the actuator.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Air Inlet Valve Actuator Replacement Air Inlet Valve Actuator Replacement
* Mode Valve Actuator Replacement Mode Valve Actuator Replacement
* Temperature Valve Actuator Replacement - Left Side Temperature Valve Actuator Replacement - Left Side
* Temperature Valve Actuator Replacement - Right Side Temperature Valve Actuator Replacement - Right Side
* Auxiliary Temperature Valve Actuator Replacement Auxiliary Temperature Valve Actuator Replacement
* Auxiliary Mode Valve Actuator Replacement Auxiliary Mode Valve Actuator Replacement
* Control Module References Control Module References for HVAC control module and HVAC Auxiliary control module or rear seat audio (RSA) replacement, setup, and programming