AutoCodes – Generic – B127C:01

B127C:01 Code - Microphone 2 Input Signal Circuit Short to Voltage

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:01 indicates Microphone 2 Input Signal Circuit Short to Voltage.
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 179

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:01 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 short to voltage is detected on the specified (+) or (−) signal circuit for more than 1.5 seconds

OBDII Code B127C:01 - Microphone 2 Input Signal Circuit Short to Voltage - AutoCodes.com — B127C:01 Code - Microphone 2 Input Signal Circuit Short to Voltage

What does this mean?

What are the Possible Causes of the DTC B127C:01?

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:01?

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:01 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:01 Code

1. What are the common symptoms of OBDII code B127C:01?

The common symptoms of OBDII code B127C:01, Microphone 2 Input Signal Circuit Short to Voltage, may include issues with the audio system, such as no sound from the microphone or distorted sound quality.

2. What can cause the Microphone 2 Input Signal Circuit to short to voltage?

The Microphone 2 Input Signal Circuit shorting to voltage can be caused by damaged wiring, a faulty microphone, or a problem with the audio system's circuitry.

3. How can I diagnose the issue related to OBDII code B127C:01?

To diagnose the issue, you can start by checking the wiring and connections related to the microphone, inspecting the microphone itself for any visible damage, and using a diagnostic tool to scan for the specific fault code.

4. Can I repair OBDII code B127C:01 myself?

Repairing OBDII code B127C:01 may require basic automotive repair knowledge and tools. If you are comfortable working with electrical components and have access to a wiring diagram for your vehicle, you may be able to repair the issue yourself.

5. What are the potential risks of ignoring OBDII code B127C:01?

Ignoring OBDII code B127C:01 can lead to continued issues with the audio system, affecting your ability to use features like hands-free calling or voice commands. It's best to address the problem promptly to prevent further damage.

6. Is it safe to continue driving with OBDII code B127C:01?

While OBDII code B127C:01 is not a critical issue that affects the drivability or safety of the vehicle, it is recommended to address the problem to ensure the proper functioning of the audio system.

7. How much does it typically cost to repair OBDII code B127C:01?

The cost of repairing OBDII code B127C:01 can vary depending on the root cause of the issue, the extent of the repair needed, and whether you choose to do the repair yourself or take your vehicle to a professional mechanic.

8. Can resetting the OBDII system clear the B127C:01 fault code?

Resetting the OBDII system may temporarily clear the fault code, but if the underlying issue causing code B127C:01 is not addressed, the code is likely to reappear. It's important to diagnose and repair the root cause of the problem.

9. Are there any recalls or technical service bulletins related to OBDII code B127C:01?

It's recommended to check with your vehicle manufacturer or a trusted mechanic to see if there are any recalls or technical service bulletins related to OBDII code B127C:01 for your specific make and model.

10. How long does it typically take to repair OBDII code B127C:01?

The time it takes to repair OBDII code B127C:01 can vary depending on the complexity of the issue and the availability of parts. Simple repairs may take a few hours, while more involved repairs could take longer.