Fault 1564 Microphone 1 B129B 13 [009] Open Circuit

[Mikeso51]

Just done a VCDS autoscan on the Polo 6C Blue GT for the first time. All ok apart from 1 minor fault in module 5F:

1564 - microphone 1
B129B 13 [009] - Open Circuit

The only microphone I'm aware of is in the interior roof light assembly, so I removed this and did some checking. Unplugging the microphone and checking it with a multimeter it reads around 5k ohms, and this varies a bit when the microphone is rubbed, so I'm guessing it's working. Certainly not open circuit. Connecting the meter to the cable going to the MMI unit, I get a reading of around 60k ohms, which seems plausible. Again, not open circuit - it's certainly connected to something. So I'm now rather stuck. I don't have any circuit diagrams so it's hard to investigate any further.

Does anyone have any experience of this particular fault and/or access to the relevant circuit diagram?

Thanks

Mike

[RUM4MO]

Have you checked that the microphone actually works okay, if so, just clear that logged fault, and check again in the future to see if it continues to get logged as a fault.

[Mikeso51]

Rather difficult to verify the microphone is ok without knowing what its characteristics should be - I have been unable to find any technical specification for the part. As I said, it has a relatively low resistance which varies when stimulated, so maybe ok. Tried clearing the fault code, but it came straight back after cycling the ignition.