AutoCodes – GMC – B127D 2014 GMC Sierra

B127D 2014 GMC Sierra Code - Microphone 3 Input Signal Circuit

Quick Answer

The active noise cancellation system uses three microphones in the vehicle headliner: one above each front seating position, and one above the rear seat. Common causes include Faulty Radio Volume Compensator Interior Noise Microphone, Radio Volume Compensator Interior Noise Microphone harness is open or shorted, Radio Volume Compensator Interior Noise Microphone circuit poor electrical connection. Severity is Low - monitor the vehicle and repair when practical. The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

What it means: B127D 2014 GMC Sierra indicates Microphone 3 Input Signal Circuit.
Common causes: Common causes include Faulty Radio Volume Compensator Interior Noise Microphone, Radio Volume Compensator Interior Noise Microphone harness is open or shorted, Radio Volume Compensator Interior Noise Microphone circuit poor electrical connection.
Severity: Low - monitor the vehicle and repair when practical.
Can I drive?: The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

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Code Popularity 183

How popular is this code, among other codes? Low

Repair Importance Level

Low (Monitor) (1 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Nov 29, 2024

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code B127D 2014 GMC Sierra Description

The active noise cancellation system uses three microphones in the vehicle headliner: one above each front seating position, and one above the rear seat. The Audio Amplifier provides a bias voltage to each microphone (+) and (-) signal circuit for the operation of the microphone. The microphones monitor the vehicle cabin for undesirable engine sounds. The Audio Amplifier uses the microphone inputs and an engine RPM signal to determine the frequency of the undesirable sound. The Diagnostic Trouble Code (DTC) will be set when a fault is detected on the specified (+) or (−) signal circuit for more than 1.5 seconds.

OBDII Code B127D 2014 GMC Sierra - Microphone 3 Input Signal Circuit - AutoCodes.com — B127D 2014 GMC Sierra Code - Microphone 3 Input Signal Circuit

What does this mean?

What are the Possible Causes of the DTC B127D 2014 GMC Sierra?

Faulty Radio Volume Compensator Interior Noise Microphone
Radio Volume Compensator Interior Noise Microphone harness is open or shorted
Radio Volume Compensator Interior Noise Microphone circuit poor electrical connection
Faulty Audio Amplifier

How to Fix the DTC B127D 2014 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 does this mean?

Code Tech Notes

Installation of aftermarket replacement speakers, additional speakers/subwoofers, or aftermarket exhaust systems can cause undesirable behavior of the active noise cancellation system. The noise reduction microphones have foam blocks above them to seal the microphones and aid in the reduction of headliner vibration. Missing or out of place foam blocks can impact system performance.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B127D 2014 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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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B127D 2014 GMC Sierra Code

1. What does OBDII code B127D mean on a 2014 GMC Sierra?

B127D indicates an issue with the Microphone 3 Input Signal Circuit, which monitors the input from the vehicle's third microphone, typically used in noise cancellation or voice recognition systems.

2. What are the common symptoms of code B127D on a 2014 GMC Sierra?

Symptoms may include poor audio quality during hands-free calls, failure of voice recognition systems, or error messages related to the audio or infotainment system.

3. What causes code B127D to appear?

This code can be triggered by a faulty microphone, damaged wiring or connectors in the microphone circuit, or a malfunctioning infotainment control module.

4. How do I diagnose code B127D on my GMC Sierra?

Start by inspecting the microphone wiring and connectors for damage or corrosion. If no issues are found, test the microphone and associated circuits using a multimeter to check for continuity or short circuits.

5. Can a software issue cause the B127D code?

Yes, a software glitch in the infotainment system or control module may cause this code. Updating or reprogramming the software may resolve the issue in some cases.

6. How do I fix the B127D code on a 2014 GMC Sierra?

Repairs may involve replacing a faulty microphone, repairing damaged wiring or connectors, or reprogramming the infotainment system. In some cases, replacing the control module may be necessary.

7. Can I drive my GMC Sierra with code B127D?

Yes, this code does not typically affect the drivability of the vehicle, but it may impact voice recognition and hands-free communication features.

8. How much does it cost to fix code B127D on a GMC Sierra?

Repair costs vary depending on the issue. Replacing a microphone may cost $50â€“$150, while more extensive repairs like wiring or module replacement can cost $200â€“$500 or more.

9. Is code B127D covered under warranty in a 2014 GMC Sierra?

If your vehicle is still under warranty and the issue is related to a manufacturing defect, it may be covered. Check with your dealership for warranty details.

10. Can a DIYer fix the B127D code?

Yes, if you have basic automotive knowledge and tools, you can inspect the wiring and replace a faulty microphone. However, reprogramming the infotainment module may require professional assistance.