High pitched sound in the cabin

[MidnightJunkie]

Hi fellow members.

Been a member for a couple of months now, but I am not sure if anyone have posted anything around this topic.

I have owned my first 2009 BMW 320i for 5 months now with no problems but when I started the car yesterday a strange High pitched sound presented itself in the cabin near the back.

I have searched the internet and found people saying that it is the differential bearing, so I tested this. I turned the ignition to ACC mode (not starting the car) and the sound was still there.

Then I found people saying that it is related to the audio system, specifically the head unit or a bad ground. So I checked this as well. I turned the car off from ACC mode (so that only the radio remains on) and the sound was gone.

This then reveals that it propably is a vacuum hose for the fuel pump or something, I am not sure. Any advice will be apreciated.

Thanks a lot in advance.




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[viven]

Hi midnight junkie,

I had a similar issue and it was definitely the exhaust vacuum pipe on my car. Not sure if this would be the cause of your issue but definitely worth checking as BMW went through all the same checks you did and eventually got rid of the noise by checking the exhaust vacuum pipe.

 

[MidnightJunkie]

Hi Viven, will definately have a look. Have not concidered it as it is a 320i and heard they dont have a exhaust vacuum pipe


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[FerdiBotha]

I had the same issue in my car and it was caused by a faulty head unit.

Put your ear against the speakers and you should hear it. If not - it's not audio related.

 

[MidnightJunkie]

Will check thanks


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