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B1277 Cadillac Code - Microphone 1 Input Signal Circuit

- Code Popularity: 903 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC B1277 Cadillac?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • 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)
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How to Fix the DTC B1277 Cadillac?

Review the 'Possible Causes' mentioned above and visually examine the corresponding wiring harness and connectors. Ensure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.

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.

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B1277 Cadillac code, it typically requires 1.0 hour of labor. The specific diagnosis time and labor rates at auto repair shops can differ based on factors such as the location, make and model of the vehicle, and even the engine type. It is common for most auto repair shops to charge between $75 and $150 per hour.

What are Code Possible Symptoms?

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

Code B1277 Cadillac Description

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.

OBDII Code B1277 Cadillac - Microphone 1 Input Signal Circuit - AutoCodes.com
B1277 Cadillac Code - Microphone 1 Input Signal Circuit

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Code B1277 Cadillac comments

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