Engine-Codes -
Generic -
B127C
B127C - Microphone 2 Input Signal Circuit
B127C Possible Causes
- 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 do I fix code B127C
Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.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.Cost of diagnosing the B127C code
Labor: 1.0
The cost of diagnosing the B127C code is 1.0 hour of labor. The auto repair labor rates vary widely across the country, and even within the same city. Most auto repairs shops charge between $75 and $150 per hour.Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
B127C Meaning
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 circuits for 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 Audio Amplifier performs a self diagnostic of the microphone circuits 16 seconds after initial power up, then periodically every 400 milliseconds thereafter.B127C More Information
Need more information on how to fix the B127C code?Get Access to Factory Service Manuals
Information for specific makes
- B127C BUICK Microphone 2 Input Signal Circuit
- B127C CADILLAC Microphone 2 Input Signal Circuit
- B127C CHEVROLET Microphone 2 Input Signal Circuit
- B127C FORD Ambient Lighting Zone 2 Output Red LED Circuit
- B127C GMC Microphone 2 Input Signal Circuit
- B127C LINCOLN Ambient Lighting Zone 2 Output Red LED Circuit
- B127C MERCURY Ambient Lighting Zone 2 Output Red LED Circuit