AutoCodes – GMC – B127C 2015 GMC Sierra

B127C 2015 GMC Sierra Code - Microphone 2 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: B127C 2015 GMC Sierra indicates Microphone 2 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 197

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 B127C 2015 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 B127C 2015 GMC Sierra - Microphone 2 Input Signal Circuit - AutoCodes.com — B127C 2015 GMC Sierra Code - Microphone 2 Input Signal Circuit

What does this mean?

What are the Possible Causes of the DTC B127C 2015 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 B127C 2015 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 B127C 2015 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 B127C 2015 GMC Sierra Code

1. What are the common symptoms of OBDII code B127C in a 2015 GMC Sierra related to the Microphone 2 Input Signal Circuit?

The common symptoms include issues with the hands-free calling system, poor sound quality during phone calls, and malfunctioning voice command functions.

2. What are the possible causes of the B127C trouble code in a 2015 GMC Sierra?

Potential causes of the B127C code include a faulty microphone, damaged wiring in the microphone circuit, or a problem with the audio control module.

3. How can I diagnose the Microphone 2 Input Signal Circuit issue in my 2015 GMC Sierra?

To diagnose the problem, start by checking the microphone connections, inspecting the wiring for any damage, and testing the microphone itself for proper functionality. You may also need to scan the vehicle with an OBDII scanner to retrieve specific diagnostic trouble codes.

4. Can I repair the B127C code issue in my 2015 GMC Sierra on my own?

If you have experience working with automotive electrical systems, you may be able to repair the Microphone 2 Input Signal Circuit problem on your own. However, if you're unsure or lack the necessary tools, it's recommended to seek professional help.

5. Is it safe to continue driving my 2015 GMC Sierra with the B127C trouble code?

While the B127C code related to the Microphone 2 Input Signal Circuit may not directly affect the drivability of your vehicle, it's essential to address the issue promptly to ensure the proper functioning of your hands-free communication system.

6. How much does it typically cost to repair the Microphone 2 Input Signal Circuit problem in a 2015 GMC Sierra?

The cost of repairing the B127C code can vary depending on the exact cause of the issue. It's advisable to get a diagnostic assessment from a qualified mechanic to determine the cost of repairs.

7. Are there any preventive measures I can take to avoid the B127C trouble code in my 2015 GMC Sierra?

To prevent the recurrence of the Microphone 2 Input Signal Circuit problem, it's advisable to handle the vehicle's electronics with care, avoid water damage to the microphone components, and conduct regular maintenance checks on the hands-free system.

8. Can a faulty microphone cause other issues in my 2015 GMC Sierra besides triggering the B127C trouble code?

Yes, a faulty microphone can impact various features of the hands-free calling system, such as voice recognition, sound quality, and call clarity. Addressing the microphone issue promptly can help maintain the overall functionality of the system.

9. How long does it typically take to repair the Microphone 2 Input Signal Circuit issue in a 2015 GMC Sierra?

The repair time for the B127C trouble code can vary based on the complexity of the problem and the availability of parts. It's recommended to consult with a professional technician to get an accurate estimate of the repair duration.

10. Will resetting the OBDII system clear the B127C trouble code in my 2015 GMC Sierra?

Resetting the OBDII system may temporarily clear the trouble code, but it's crucial to address the underlying issue causing the B127C code to prevent it from reoccurring. Simply clearing the code without addressing the root cause may lead to further problems.