B0413

DTC B0413

Diagnostic Instructions

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

DTC Descriptors

DTC B0413 05
- Temperature Control 1 Feedback Circuit Short to Battery or Open

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

DTC B0413 08
- Temperature Control 1 Feedback Circuit Signal Invalid

Diagnostic Fault Information






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 a 12-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 air temperature door position differs from the commanded door position.

Action Taken When the DTC Sets

Driver A and driver B circuits are deactivated for the air temperature 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.

Circuit/System Verification

Ignition ON, adjust the mode actuator to panel or vent position, command the air temperature actuator to full hot then full cold at the HVAC control head. The air temperature should change appropriately.

Circuit/System Testing

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

• If greater than 1 ohm, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.

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

• If less than 4.8 volts, 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 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the HVAC control module.

4. Install a 3-amp fused jumper wire at the signal circuit terminal D, test for greater than 5 volts. Toggle the jumper wire between the low reference circuit terminal E and the 5-volt reference circuit terminal C.

• If the position signal parameter is less than 5 volts, test the signal circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace the HVAC control module.

5. Ignition ON, after 30 seconds verify that a test lamp illuminates between control circuit A 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, test the B+ circuit of the HVAC control module for a short to ground, high resistance, or an open. If the circuit tests normal, test the HVAC control module ground circuit for a high resistance or an open. If the circuit tests normal, replace the HVAC control module.

6. Ignition OFF, verify that a test lamp does not illuminate between control circuit terminal A terminal and B+.

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

7. 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, test the B+ circuit of the HVAC control module for a short to ground, high resistance, or an open. If the circuit tests normal, test the HVAC control module ground circuit for a high resistance or an open. If the circuit tests normal, replace the HVAC control module.

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

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

9. If all circuits test normal, replace the air temperature actuator.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* * Refer to Programming and Relearning for HVAC control module setup and programming. Programming and Relearning

* Air Temperature Actuator Replacement