B374A:05 GMC Code - Air Flow Control Position Feedback Circuit Short To Battery Or Open
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:05 GMC indicates Air Flow Control Position Feedback Circuit Short To Battery Or Open.
- 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:05 GMC 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:05 GMC?
- 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:05 GMC?
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:05 GMC 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 GMC Models
- B374A 2014 GMC Sierra — Air Flow Control Position Feedback Circuit
- B374A 2015 GMC Sierra — Air Flow Control Position Feedback Circuit
- B374A 2016 GMC Sierra — Air Flow Control Position Feedback Circuit
- B374A 2017 GMC Sierra — Air Flow Control Position Feedback Circuit
- B374A 2018 GMC Sierra — Air Flow Control Position Feedback Circuit
Frequently Asked Questions about B374A:05 GMC Code
1. What does the OBDII code B374A:05 mean on a GMC vehicle?
The code B374A:05 indicates an issue with the Air Flow Control Position Feedback Circuit, specifically a short to battery or an open circuit.
2. What are common symptoms of the B374A:05 code in GMC vehicles?
Symptoms may include poor HVAC airflow control, inability to adjust air direction, or the HVAC system being stuck in one mode.
3. What causes the B374A:05 code to trigger?
Common causes include a damaged wiring harness, a faulty air flow control actuator, a shorted or open circuit in the feedback wiring, or a malfunctioning HVAC control module.
4. Can I drive my GMC with the B374A:05 code?
Yes, but you may experience discomfort due to limited HVAC functionality. The code doesn’t typically affect drivability but should be addressed to restore proper air control.
5. How can I diagnose the B374A:05 code?
Diagnosis involves inspecting the wiring and connectors for damage, testing the air flow control actuator for proper operation, and checking for voltage and continuity in the feedback circuit.
6. How do I fix the B374A:05 code on a GMC?
Repairs may include replacing a damaged air flow control actuator, repairing or replacing faulty wiring or connectors, or reprogramming or replacing the HVAC control module.
7. How much does it cost to repair the B374A:05 code?
Costs vary depending on the repair. Replacing an actuator typically costs $150-$300, while wiring repairs may cost $50-$200, plus labor.
8. Can a blown fuse cause the B374A:05 code?
While a blown fuse is less common for this specific code, it’s still worth checking the HVAC-related fuses as part of your diagnostic process.
9. Will resetting the code fix the B374A:05 issue?
Resetting the code may clear it temporarily, but the underlying issue must be repaired to prevent the code from returning.
10. Is the B374A:05 code related to other HVAC problems?
Yes, this code can be associated with issues like improper air temperature control or other actuator-related malfunctions in the HVAC system.
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