B374A:61 Code - Air Flow Control Position Feedback Circuit Stuck
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:61 indicates Air Flow Control Position Feedback Circuit Stuck.
- 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:61 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 less than 0.1 V for more than 50 ms.
What are the Possible Causes of the DTC B374A:61?
- 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:61?
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:61 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:61 Buick — Air Flow Control Position Feedback Circuit Stuck
- B374A:61 Cadillac — Air Flow Control Position Feedback Circuit Stuck
- B374A:61 Chevrolet — Air Flow Control Position Feedback Circuit Stuck
- B374A:61 GMC — Air Flow Control Position Feedback Circuit Stuck
Frequently Asked Questions about B374A:61 Code
What does the OBDII code B374A:61 mean?
This code indicates that the Air Flow Control Position Feedback Circuit is stuck, suggesting an issue with the actuator or related components controlling airflow.
What are common symptoms of code B374A:61?
Symptoms may include improper air distribution in the HVAC system, reduced heating or cooling performance, or unusual noises from the dashboard.
What causes the B374A:61 code to trigger?
Common causes include a faulty air flow control actuator, damaged wiring or connectors, or mechanical obstructions preventing the actuator from moving.
Can I still drive my vehicle with code B374A:61?
Yes, you can drive the vehicle, but the HVAC system may not function correctly, leading to discomfort or reduced climate control efficiency.
How is code B374A:61 diagnosed?
A technician will typically inspect the air flow control actuator, check the wiring and connections for damage, and use a scan tool to monitor the actuator's position feedback.
What tools are needed to repair code B374A:61?
You may need a multimeter, a scan tool, and basic hand tools to test the wiring and replace the actuator if necessary.
How do you fix code B374A:61?
Repairs often involve replacing the faulty air flow control actuator, repairing damaged wiring, or clearing any obstructions in the system.
Can a bad fuse cause code B374A:61?
While unlikely, a blown fuse linked to the HVAC system could potentially cause issues leading to this code. Inspect all related fuses.
Is code B374A:61 related to the blower motor?
No, this code is specific to the air flow control actuator circuit, not the blower motor itself.
Will clearing the code fix the problem?
Clearing the code will not resolve the underlying issue; the stuck actuator or circuit problem must be repaired to prevent the code from returning.
Discuss the causes and fixes for B374A:61 OBDII Code
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