Diagnostic Instructions

DTC Descriptors

DTC B0248 61: Air Flow Control 3 Circuit Actuator Stuck

DTC B0268 61: Air Flow Control 7 Circuit Actuator Stuck

DTC B0408 61: Temperature Control 1 Circuit Actuator Stuck

DTC B0413 06: Temperature Control 1 Feedback Circuit Short to Ground or Open

DTC B0418 61: Temperature Control 2 Circuit Actuator Stuck

DTC B0423 06: Temperature Control 2 Feedback Circuit Short to Ground or Open

DTC B3761 06: Air Flow Control 3 Feedback Circuit Short to Ground or Open

DTC B3773 06: Air Flow Control 7 Feedback Circuit Short to Ground or Open

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Recirculation 5-Volt Reference	B0248 61, B0408 61, B0418 61, B0268 61	B3773 06	B0268 61, B3773 06	--
Recirculation Door Position Signal	B0268 61	B3773 06	B0268 61, B3773 06	--
Recirculation Door Control A	B0268 61	B0268 61	B0268 61	--
Recirculation Door Control B	B0268 61	B0268 61	B0268 61	--
Recirculation Low Reference	--	B0268 61	--	--
Driver Air Temperature 5-Volt Reference	B0248 61, B0408 61, B0418 61, B0268 61	B0413 06	B0408 61, B0413 06	--
Driver Air Temperature Door Position Signal	B0408 61	B0413 06	B0408 61, B0413 06	--
Driver Air Temperature Door Control A	B0408 61	B0408 61	B0408 61	--
Driver Air Temperature Door Control B	B0408 61	B0408 61	B0408 61	--
Driver Air Temperature Low Reference	--	B0408 61	--	--
Passenger Air Temperature 5-Volt Reference	B0248 61, B0408 61, B0418 61, B0268 61	B0418 61	B0268 61, B0423 06	--
Passenger Air Temperature Door Position Signal	B0418 61	B0268 61, B0423 06	B0418 61	--
Passenger Air Temperature Door Control A	B0418 61	B0418 61	B0418 61	--
Passenger Air Temperature Door Control B	B0418 61	B0418 61	B0418 61	--
Passenger Air Temperature Low Reference	--	B0418 61	--	--
Mode 5-Volt Reference	B0248 61, B0408 61, B0418 61, B0268 61	B0248 61	B0248 61, B3761 06	--
Mode Door Position Signal	B0248 61	B0248 61, B3761 06	B0248 61, B3761 06	--
Mode Door Control A	B0248 61	B0248 61	B0248 61	--
Mode Door Control B	B0248 61	B0248 61	B0248 61	--
Mode Low Reference	--	B0248 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 module controls the direction of the actuator door by changing the polarity of the control circuits.

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 7 counts or greater than 250 counts.

Action Taken When the DTC Sets

Control A and control B circuits are deactivated for the appropriate actuator. The driver information center (DIC) will display SERVICE A/C SYSTEM.

Conditions for Clearing the DTC

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Automatic HVAC 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 to 100 percent with a scan tool. The scan tool should display between 224 and 230 counts on the mode actuator, all other actuators should display between 199 and 205 counts.

Circuit/System Testing

1. Ignition OFF, disconnect the X1 harness connector at the HVAC control module.
2. Ignition ON, Verify that a test lamp illuminates between the B+ circuit terminal 18 and ground.

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

3. Ignition OFF, connect the harness connector at the HVAC control module and disconnect the harness connector at the appropriate actuator.
4. Ignition OFF, test for less than 10 ohms between the following low reference circuit terminal and ground.

•	Air temperature actuator-left terminal 1

•	Air temperature actuator-right terminal 2

•	Mode actuator terminal 2

•	Recirculation actuator terminal 1

⇒	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.

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

•	Air temperature actuator-left terminal 2

•	Air temperature actuator-right terminal 1

•	Mode actuator terminal 1

•	Recirculation actuator terminal 3

⇒	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.

6. Verify the scan tool Door Position parameter is greater than 250 counts.

⇒	If less than the specified range, test the following signal circuit for a short to ground. If the circuit tests normal, replace the HVAC control module.

•	Air temperature actuator-left terminal 3

•	Air temperature actuator-right terminal 3

•	Mode actuator terminal 3

•	Recirculation actuator terminal 5

7. Install a 3A fused jumper wire between the following signal circuit terminal and the low reference circuit terminal. Verify the scan tool Door Position parameter is less than 3 counts.

•	Air temperature actuator-left terminal 3 and terminal 1

•	Air temperature actuator-right terminal 3 and terminal 2

•	Mode actuator terminal 3 and terminal 2

•	Recirculation actuator terminal 5 and terminal 1

⇒	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.

8. Ignition OFF, test for less than 10 ohms between the following control circuit terminal and ground.

•	Air temperature actuator-left terminal 5

•	Air temperature actuator-right terminal 5

•	Mode actuator terminal 5

•	Recirculation actuator terminal 6

⇒	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. Ignition OFF, test for less than 10 ohms between the following control circuit terminal and ground.

•	Air temperature actuator-left terminal 4

•	Air temperature actuator-right terminal 4

•	Mode actuator terminal 4

•	Recirculation actuator terminal 7

⇒	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.

10. Connect a test lamp between following control circuit terminals.

•	Air temperature actuator-left terminal 5 and terminal 4

•	Air temperature actuator-right terminal 5 and terminal 4

•	Mode actuator terminal 5 and terminal 4

•	Recirculation actuator terminal 6 and terminal 7

11. 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.

12. If both circuits test normal, test or replace the actuator.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.