AutoCodes – Generic – B127C:02

B127C:02 Code - Microphone 2 Input Signal Circuit Short to Ground

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:02 indicates Microphone 2 Input Signal Circuit Short to Ground.
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 552

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:02 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 ground is detected on the specified (+) or (−) signal circuit for more than 1.5 seconds

OBDII Code B127C:02 - Microphone 2 Input Signal Circuit Short to Ground - AutoCodes.com — B127C:02 Code - Microphone 2 Input Signal Circuit Short to Ground

What does this mean?

What are the Possible Causes of the DTC B127C:02?

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:02?

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:02 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:02 Code

What does the OBDII code B127C:02 mean?

The code B127C:02 indicates that the Microphone 2 input signal circuit has a short to ground, which can affect communication or functionality related to the microphone.

What are the common symptoms of code B127C:02?

Symptoms can include inoperable voice commands, issues with hands-free calling, or poor microphone audio quality during phone calls or voice recognition use.

What causes the B127C:02 code to appear?

Common causes include damaged microphone wiring, a shorted circuit, a defective microphone, or a faulty audio control module.

How can I diagnose the B127C:02 code?

Begin by inspecting the wiring and connectors for signs of damage or corrosion. Use a multimeter to check for continuity in the microphone circuit and confirm if there's a short to ground.

Can a faulty microphone trigger the B127C:02 code?

Yes, a defective or internally shorted microphone can cause this code to set.

Is the B127C:02 code related to Bluetooth or voice command issues?

Yes, since the microphone is often used for these functions, this code can lead to problems with Bluetooth calls or voice recognition failing to work.

How do I fix the B127C:02 code?

Repairs may include replacing damaged wiring, repairing connectors, or replacing the defective microphone. In some cases, reprogramming or replacing the audio control module may be necessary.

Can I still drive my car with the B127C:02 code?

Yes, this code typically does not affect the drivability of your car, but it can impair features like Bluetooth communication and voice commands.

How much does it cost to repair the B127C:02 code?

Repair costs depend on the specific issue but may range from $50 to $200 for wiring repairs or microphone replacement. Module replacement could be more expensive.

Can I clear the B127C:02 code without fixing it?

Clearing the code with an OBDII scanner may temporarily remove it, but if the underlying issue isn't resolved, the code will likely return.