B374A 2014 GMC Sierra Code - Air Flow Control Position Feedback Circuit
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 2014 GMC Sierra indicates Air Flow Control Position Feedback Circuit.
- 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.
Code B374A 2014 GMC Sierra Description
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.
What are the Possible Causes of the DTC B374A 2014 GMC Sierra?
- 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 2014 GMC Sierra?
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 2014 GMC Sierra 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.
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Frequently Asked Questions about B374A 2014 GMC Sierra Code
1. What does the OBDII code B374A mean on a 2014 GMC Sierra?
The code B374A refers to an issue with the Air Flow Control Position Feedback Circuit, which monitors the position of the air flow control actuator in the HVAC system.
2. What are common symptoms of the B374A code in a 2014 GMC Sierra?
Symptoms include improper air distribution from the vents, difficulty switching between vent modes, and inconsistent cabin airflow.
3. What causes the B374A code to appear?
Common causes include a faulty air flow control actuator, damaged wiring or connectors in the feedback circuit, or a malfunctioning HVAC control module.
4. Can I drive my 2014 GMC Sierra with the B374A code?
Yes, you can drive with this code, but the HVAC system might not function correctly, leading to reduced comfort or inability to control airflow.
5. How do I diagnose the B374A code in my GMC Sierra?
Diagnosis involves checking for damaged or loose wiring, testing the air flow control actuator, and using a scan tool to monitor feedback signals.
6. What tools are needed to fix the B374A code?
A diagnostic scan tool, multimeter, and basic hand tools are typically required to diagnose and repair this issue.
7. How much does it cost to repair the B374A code on a 2014 GMC Sierra?
Repair costs vary but generally range from $150 to $400, depending on whether the air flow control actuator or wiring needs replacement.
8. Can a faulty HVAC control module cause the B374A code?
Yes, a malfunctioning HVAC control module can send incorrect signals, triggering this code.
9. How can I prevent the B374A code from occurring?
Regular maintenance of the HVAC system, inspecting wiring for damage, and avoiding extreme force when switching vent modes can help prevent this issue.
10. Do I need to clear the B374A code after repairs?
Yes, after completing repairs, clear the code using a scan tool and test the system to ensure the issue is resolved.
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