B374A:02 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 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.
Code B374A:02 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.
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.
What are the Possible Causes of the DTC B374A:02?
- 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?
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 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 Makes
- B374A:02 Buick — Air Flow Control Position Feedback Circuit Short To Ground
- B374A:02 Cadillac — Air Flow Control Position Feedback Circuit Short To Ground
- B374A:02 Chevrolet — Air Flow Control Position Feedback Circuit Short To Ground
- B374A:02 GMC — Air Flow Control Position Feedback Circuit Short To Ground
Frequently Asked Questions about B374A:02 Code
What does OBDII code B374A:02 mean?
The code B374A:02 refers to an issue in the Air Flow Control Position Feedback Circuit, specifically a short to ground, which affects the vehicle's ability to regulate airflow properly.
What are the common symptoms of code B374A:02?
Symptoms may include poor HVAC airflow, inability to adjust air direction or temperature, unusual clicking noises from the HVAC system, and potentially an illuminated check engine or HVAC system warning light.
What causes the B374A:02 code to appear?
The most common causes are damaged wiring, a short to ground in the feedback circuit, a faulty airflow control motor, or a malfunctioning HVAC control module.
How can I diagnose the B374A:02 code?
Start by visually inspecting the wiring and connectors for damage or corrosion. Use a multimeter to check for continuity in the circuit and ensure there is no short to ground. If wiring is intact, test the airflow control motor and feedback sensor.
Can I drive my car with the B374A:02 code?
Yes, you can usually drive with this code, but the HVAC system may not function correctly, leading to discomfort in extreme weather conditions.
How do I fix the B374A:02 code?
Repairs may involve fixing or replacing damaged wiring, connectors, or the airflow control motor. In some cases, the HVAC control module may need reprogramming or replacement.
Does clearing the code fix the issue?
Clearing the code will turn off the warning light temporarily, but if the underlying issue is not resolved, the code will likely return.
How much does it cost to repair the B374A:02 code?
Repair costs vary depending on the issue but can range from $50 for simple wiring repairs to $500 or more if the airflow control motor or HVAC control module needs replacement.
Can a blown fuse cause the B374A:02 code?
Yes, a blown fuse in the HVAC system can interrupt the circuit and potentially trigger this code. Check the relevant fuses as part of your diagnosis.
Does the B374A:02 code affect the engine performance?
No, this code typically only affects the HVAC system and does not directly impact engine performance. However, it can reduce cabin comfort.
Discuss the causes and fixes for B374A:02 OBDII Code
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