AutoCodes – GMC – B374A:02 GMC

B374A:02 GMC Code - Air Flow Control Position Feedback Circuit Short To Ground

Quick Answer

Doors in the Heating, Ventilation, and Air Conditioning (HVAC) case assembly are used to control airflow. Common causes include Faulty Mode Actuator, Mode Actuator harness is open or shorted, Mode Actuator circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: B374A:02 GMC indicates Air Flow Control Position Feedback Circuit Short To Ground.
Common causes: Common causes include Faulty Mode Actuator, Mode Actuator harness is open or shorted, Mode Actuator circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 431

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 29, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B374A:02 GMC Description

Doors in the Heating, Ventilation, and Air Conditioning (HVAC) case assembly are used to control airflow. The HVAC control module operates the doors using actuators, with one actuator being used for each door. The system has the following air control doors and associated actuators: mode, left and right temperature, and recirculation. When equipped with auxiliary HVAC controls 2 additional actuators are added for auxiliary (rear) mode and temperature.
Each actuator used in the system is a 5-wire bi-directional electric motor that incorporates a feedback potentiometer. The five circuits are low reference, 5 V reference, actuator position signal, and two control circuits. The control circuits use either ground or 12 V value to coordinate the actuator movement. In order to move the actuator, the HVAC control module grounds one of the control circuits while providing the other with 12 V. The HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction.
When the actuator shaft rotates, the potentiometer's sliding contact changes the door position signal between 0-5 V. The HVAC control module converts the voltage signal to counts. The total range of the counts is 0-1024, with an operating range between 20-1000. The actual operating range of an actuator is determined during calibration. During calibration, the actuator is moved through its full range of travel, and the module stores the minimum and maximum value. Based on the desired system operation, the module sets a commanded, or targeted, value for the actuators. The control circuits are operated to move the door to the required position, and the changing position signal is sent to the module. Once the actual position signal and the commanded value are the same, the module ceases operating the control circuits and the actuator (and door) remains in the desired position.
The Diagnostic Trouble Code (DTC) will be set when the HVAC control module detects the sensor signal out of range. The signal voltage is greater than 4.9 V for more than 50 ms.

OBDII Code B374A:02 GMC - Air Flow Control Position Feedback Circuit Short To Ground - AutoCodes.com — B374A:02 GMC Code - Air Flow Control Position Feedback Circuit Short To Ground

What does this mean?

What are the Possible Causes of the DTC B374A:02 GMC?

Faulty Mode Actuator
Mode Actuator harness is open or shorted
Mode Actuator circuit poor electrical connection
Faulty Heating, Ventilation, and Air Conditioning (HVAC) Control Module

How to Fix the DTC B374A:02 GMC?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B374A:02 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the B374A:02 GMC code?

Need more information on how to fix the B374A:02 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B374A:02 GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

B374A 2014 GMC Sierra — Air Flow Control Position Feedback Circuit
B374A 2015 GMC Sierra — Air Flow Control Position Feedback Circuit
B374A 2016 GMC Sierra — Air Flow Control Position Feedback Circuit
B374A 2017 GMC Sierra — Air Flow Control Position Feedback Circuit
B374A 2018 GMC Sierra — Air Flow Control Position Feedback Circuit

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B374A:02 GMC Code

1. What does the OBDII code B374A:02 mean for a GMC vehicle?

The code B374A:02 indicates an issue with the Air Flow Control Position Feedback Circuit, specifically a short to ground.

2. What are common symptoms of code B374A:02 in a GMC vehicle?

Symptoms may include reduced HVAC functionality, inability to control airflow direction, unusual noises from the HVAC system, or a persistent check engine light.

3. What causes the B374A:02 code to appear on a GMC vehicle?

This code is typically caused by damaged wiring, a short circuit, a faulty actuator, or issues with the HVAC control module.

4. Can I continue driving with the B374A:02 code active in my GMC vehicle?

While the vehicle may still be drivable, HVAC functionality could be compromised. Itâ€™s best to address the issue promptly to avoid further damage.

5. How do I diagnose the B374A:02 code on my GMC vehicle?

Start by inspecting the wiring and connectors for damage or corrosion. Then, test the actuator and control module for proper functionality using a multimeter or scan tool.

6. What repair options are available for fixing code B374A:02?

Repairs may include replacing damaged wiring, repairing shorts, replacing the air flow control actuator, or reprogramming/updating the HVAC control module.

7. How much does it typically cost to fix the B374A:02 code on a GMC vehicle?

Repair costs can vary widely, but fixing wiring issues may cost $100â€“$300, while actuator replacement could range from $200â€“$500, depending on labor and parts.

8. Can a malfunctioning HVAC control module cause the B374A:02 code?

Yes, a faulty HVAC control module can result in improper airflow control and trigger this code.

9. Is the B374A:02 code related to the blower motor in a GMC vehicle?

No, this code specifically refers to the air flow control position feedback circuit, not the blower motor itself.

10. How can I prevent the B374A:02 code from occurring?

Regularly inspect the HVAC system wiring and connectors for damage, avoid excessive moisture exposure, and address minor HVAC issues promptly to prevent circuit problems.