AutoCodes – Generic – B1277:04

B1277:04 Code - Microphone 1 Input Signal Circuit Open/High Resistance

Quick Answer

For Cellular, Entertainment, and Navigation Systems: The Human Machine Interface Control Module uses the cellular telephone microphone for voice recognition and cellular features. Common causes include 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). 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: B1277:04 indicates Microphone 1 Input Signal Circuit Open/High Resistance.
Common causes: Common causes include 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).
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 1,705

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 B1277:04 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 B1277:04 - Microphone 1 Input Signal Circuit Open/High Resistance - AutoCodes.com — B1277:04 Code - Microphone 1 Input Signal Circuit Open/High Resistance

What does this mean?

What are the Possible Causes of the DTC B1277:04?

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 DTC B1277:04?

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 B1277:04 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 B1277:04 Code

1. What are common symptoms of OBDII code B1277:04 (Microphone 1 Input Signal Circuit Open/High Resistance)?

- Common symptoms include loss of audio from the microphone, poor sound quality, or complete silence during phone calls or voice commands.

2. What can cause the Microphone 1 Input Signal Circuit to have an open or high resistance?

- Possible causes include damaged wiring, loose connections, a faulty microphone, or issues with the audio system's control module.

3. How can I diagnose the Microphone 1 Input Signal Circuit issue related to code B1277:04?

- You can use a multimeter to check for continuity in the wiring, inspect the microphone for physical damage, and perform a visual inspection of the connections for any loose or corroded contacts.

4. Are there any simple repairs I can attempt to fix the Microphone 1 Input Signal Circuit problem?

- Yes, you can start by checking and reseating any loose connections, repairing damaged wiring, or replacing the microphone if it is found to be faulty.

5. Will resetting the OBDII code B1277:04 make the issue with the Microphone 1 Input Signal Circuit go away?

- Resetting the code may temporarily clear the error message, but it will not fix the underlying problem causing the open or high resistance in the microphone circuit.

6. Can a DIY enthusiast without much technical knowledge fix the Microphone 1 Input Signal Circuit issue?

- Depending on the root cause, some simple repairs like checking connections or replacing the microphone can be attempted by a DIY enthusiast. However, more complex issues may require professional assistance.

7. Is it safe to continue driving with OBDII code B1277:04 (Microphone 1 Input Signal Circuit Open/High Resistance)?

- While the issue may not directly affect the vehicle's performance, it can impact your ability to use hands-free calling features or voice commands. It is recommended to address the problem to ensure safe and convenient driving.

8. How much does it typically cost to repair the Microphone 1 Input Signal Circuit issue related to OBDII code B1277:04?

- The cost of repairs can vary depending on the extent of the problem and whether professional assistance is needed. Simple fixes like reconnecting wires may cost less compared to replacing a faulty microphone or control module.

9. Are there any preventive measures to avoid encountering OBDII code B1277:04 in the future?

- Regularly inspecting and maintaining the audio system components, ensuring proper installation of aftermarket devices, and handling the wiring carefully can help prevent issues with the Microphone 1 Input Signal Circuit.