VOLVO
IHU-B1D7911 - Microphone Input. General Electrical Failures. Circuit short to ground
System
Infotainment Head Unit (IHU)
Volvo models this fault code applies to
Applies to the following models:
9 modelsS60 (2011–), S80 (2007–), V40 (2013–), V40 Cross Country (2013–), V60 (2011–), V60 Cross Country (2015–), V70 (2008–), XC60 (2009–), XC70 (2008–)
What does this fault code mean?
The infotainment head unit (IHU) monitors the microphone's signal wire. The code is stored when the signal from the microphone is too low, which points to a short-circuit to ground in the wire from the microphone.
Possible causes
- The signal wire to the microphone is short-circuited to ground
- The microphone's signal wires are shorted together
What you can do
- 1Clear the code and check whether it returns
- 2Check that the fuses are intact
- 3Make a test call using hands-free and ask the other person whether they can hear you
- 4Check that the microphone connector is firmly seated and free from oxidation, and that the wiring has no chafing or damage
- 5Use a multimeter to check that the microphone's signal wire is not short-circuited to ground
- 6If the fault remains, have a workshop trace the microphone and the wiring further
Symptoms you may notice2
- The other party cannot hear you when you use hands-free
- The other party cannot hear you, sometimes or all the time
General guidance for car owners. Diagnosis on the car can point to a different cause.