Engine-Codes - Generic - B1277

B1277 Code - Microphone 1 Input Signal Circuit

- Code Popularity: 12,525 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
Table of contents

What are the Possible Causes of the Code B1277?

  • Faulty Cellular Phone Microphone (For Cellular, Entertainment, and Navigation Systems)
  • Faulty Radio Volume Compensator Interior Noise Microphone (For Active Noise Cancellation System)
  • Faulty Audio Amplifier (For Active Noise Cancellation System)
  • Faulty Human Machine Interface Control Module or Radio (For Cellular, Entertainment, and Navigation Systems)

How to Fix the B1277 Code?

Start by checking 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.

Code B1277 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 B1277?

Labor: 1.0

The cost to diagnose the B1277 code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.

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What are Code B1277 Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

What Does the B1277 Code Mean?

For Cellular, Entertainment, and Navigation Systems:
The Human Machine Interface Control Module uses the cellular telephone microphone for voice recognition and cellular features. The Human Machine Interface Control Module provides a bias voltage to each microphone (+) and (-) signal circuit for the operation of the microphone.
The radio provides the cellular phone microphone with a supplied voltage on the cellular phone microphone high signal circuit. When the microphone is in use, voice data from the user is sent back to the radio on the cellular microphone low signal circuit.

For Active Noise Cancellation System:
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.

B1277 Code - Microphone 1 Input Signal Circuit

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Code B1277 Information for Specific Makes

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