B374A 2017 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 2017 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 2017 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 2017 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 2017 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 2017 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 2017 GMC Sierra Code
1. What does the OBDII code B374A mean on a 2017 GMC Sierra?
B374A indicates an issue with the Air Flow Control Position Feedback Circuit, which monitors the position of the HVAC system's airflow control components.
2. What are the common symptoms of code B374A on a 2017 GMC Sierra?
Symptoms may include improper airflow direction from vents, inability to change vent modes, or unusual sounds from the HVAC system.
3. What causes the B374A code to trigger on a 2017 GMC Sierra?
Common causes include a faulty airflow control actuator, damaged wiring or connectors, or a malfunction in the HVAC control module.
4. Can I drive my 2017 GMC Sierra with the B374A code?
Yes, but you may experience HVAC issues like improper vent airflow, which can affect cabin comfort. It’s best to address the issue promptly.
5. How do I diagnose the B374A code on my 2017 GMC Sierra?
Use an OBDII scanner to confirm the code, inspect the airflow control actuator and wiring for damage, and test the HVAC system functionality.
6. How do I fix the B374A code on a 2017 GMC Sierra?
Repairs may include replacing the airflow control actuator, repairing damaged wiring or connectors, or reprogramming the HVAC control module.
7. How much does it cost to repair the B374A code on a 2017 GMC Sierra?
Repair costs vary but typically range from $150 to $400 depending on whether parts like the actuator need replacement.
8. Can a weak battery trigger the B374A code on a 2017 GMC Sierra?
A weak or failing battery can sometimes cause voltage-related issues, potentially affecting the HVAC system and triggering the code.
9. Is the B374A code related to other HVAC system codes?
Yes, it can be related to other HVAC codes if multiple actuators or circuits are malfunctioning, indicating a broader system issue.
10. Do I need a professional mechanic to fix the B374A code on my 2017 GMC Sierra?
While DIY repairs are possible for experienced individuals, professional diagnostics are recommended to ensure proper repairs and system calibration.
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