B374A Chevrolet 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 Chevrolet 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 Chevrolet 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 Chevrolet?
- 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 Chevrolet?
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 Chevrolet 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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Information for Specific Chevrolet Models
- B374A 2014 Chevrolet Silverado — Air Flow Control Position Feedback Circuit
- B374A 2015 Chevrolet Silverado — Air Flow Control Position Feedback Circuit
- B374A 2016 Chevrolet Silverado — Air Flow Control Position Feedback Circuit
- B374A 2017 Chevrolet Silverado — Air Flow Control Position Feedback Circuit
- B374A 2018 Chevrolet Silverado — Air Flow Control Position Feedback Circuit
Frequently Asked Questions about B374A Chevrolet Code
1. What does the OBDII code B374A mean on a Chevrolet vehicle?
The code B374A indicates an issue with the Air Flow Control Position Feedback Circuit, which monitors the position of the air control components in the HVAC system.
2. What are common symptoms of the B374A code?
Symptoms include improper airflow from HVAC vents, inability to control air direction, and potential HVAC system performance issues.
3. What causes the B374A code to appear?
Common causes include a faulty air flow control actuator, damaged wiring in the feedback circuit, a malfunctioning HVAC control module, or electrical connector issues.
4. Can I drive my Chevrolet with the B374A code active?
Yes, the vehicle is generally safe to drive, but you may experience limited or inconsistent HVAC functionality, which could be inconvenient.
5. How do I diagnose the B374A code?
Start by visually inspecting the wiring and connectors for damage, then test the air flow control actuator and related circuits using a multimeter or scan tool to check for faults.
6. How is the B374A code typically fixed?
Repairs can include replacing the air flow control actuator, repairing or replacing damaged wiring, or reprogramming or replacing the HVAC control module.
7. What tools are needed to troubleshoot the B374A code?
You’ll need a scan tool capable of reading OBDII codes, a multimeter for checking electrical continuity, and basic hand tools for inspecting and replacing components.
8. Can a blown fuse cause the B374A code?
Yes, a blown fuse related to the HVAC system can interrupt the circuit and trigger the B374A code, so checking fuses is a good first step.
9. How much does it cost to fix the B374A code?
Repair costs vary, but replacing an air flow control actuator typically costs between $100 and $300, including parts and labor.
10. Can I clear the B374A code without repairing the issue?
You can clear the code with a scan tool, but it will likely return unless the underlying issue is resolved.
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