B1277 on 2023-2025 Land Rover Range Rover Sport — Microphone / Air Flow Control Circuit Fault
1 vehicles · 1 makes
Most Reported On
B1277 is an OBD-II diagnostic trouble code meaning “Microphone / Air Flow Control Circuit Fault.” B1277 is a manufacturer-specific body code whose meaning varies by maker: in some vehicles it indicates a microphone input signal circuit fault (affecting hands-free calling/voice commands), while in others it refers to an HVAC air-flow control door circuit being out of its commanded position. The module has detected a circuit or position reading outside expected limits. It is generally a comfort/convenience issue and not safety-critical. Confirm against your vehicle's service data for the exact subsystem. This code is most commonly reported on 2023-2025 Land Rover Range Rover Sport.
Common Causes
Diagnostic Tools
To diagnose B1277, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
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FAQ
What does B1277 mean?
B1277 stands for "Microphone / Air Flow Control Circuit Fault." B1277 is a manufacturer-specific body code whose meaning varies by maker: in some vehicles it indicates a microphone input signal circuit fault (affecting hands-free calling/voice commands), while in others it refers to an HVAC air-flow control door circuit being out of its commanded position. The module has detected a circuit or position reading outside expected limits. It is generally a comfort/convenience issue and not safety-critical. Confirm against your vehicle's service data for the exact subsystem.
What are the most common causes of B1277?
The most common causes of B1277 are: Faulty microphone or HVAC mode-door actuator (per application), Damaged wiring or connector in the affected circuit, Open or short in the signal circuit, Binding or obstructed HVAC air-distribution door (HVAC variant), Faulty audio/HVAC control module, Corroded or loose connector. The specific cause varies by vehicle.
How much does it cost to fix B1277?
Repair costs vary widely depending on the root cause and vehicle.
Which vehicles are affected by B1277?
Au7o has documented B1277 across 1 vehicle models from 1 manufacturers: Land Rover.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.