What does it mean?
B1776 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Microphone Input/Output Short to Ground/Open .
Symptoms
- Callers cannot hear the driver, or the voice level is extremely low
- Voice recognition fails to pick up commands
- Constant hum or buzz on outgoing calls
- Hands-free system reports a microphone fault or simply disables voice functions
- Problem sometimes appears only after rain or a car wash
Likely causes
- Microphone signal wire chafed against the roof panel, a headliner bracket or a grab handle bolt
- Screen of the microphone cable touching the signal conductor after the cable was crushed by a trim clip
- Water from a sunroof drain or windscreen leak soaking the microphone and grounding the circuit
- Connector at the overhead console corroded or not fully latched after interior work
- Broken conductor in the lead where it flexes at the A-pillar
- Microphone element failed internally, shorting to its metal body
- Module input stage failure
How to fix it
- Read the module codes and check whether the fault is current or historic
- Lower the overhead console or headliner edge and inspect the microphone connector for moisture, corrosion and a proper latch
- Check the sunroof drains and windscreen seal above the microphone position and dry out any wet insulation
- Measure both microphone wires for continuity end to end and for a short to ground with the module unplugged
- Follow the cable along the A-pillar and headliner, looking for crush points at clips and brackets
- Substitute a known good microphone if available to separate the element from the wiring
- Repair the harness or replace the microphone; the audio or telematics module is the last suspect