My 2012 Cooper S Hatch with the Harmon Kardon system has taken to making all manner of speaker noise both before and after shutdown. It will happen when you first get in the car, and after you turn the car off. Key in or out, doesn't matter. Nor does it matter if the radio is turned on or off.

When you first start up, the sound will continue with the radio on.

It seems to be coming from the RHS High and Mid speakers. Anybody had this happen to them? I plan on calling up the dealer this week.

 

Is there any correlation to the noise and your cell phone? I have seen few instances where that will happen with a cell phone in proximity to the affected speaker. For that matter, it could be a 3G or 4G wireless device like an iPad. Just an idea.

 

Exactly the same thought I had when I heard the sound: cell phone EM interference. I've heard the same sound coming out of a 1980's-vintage clock radio speaker, computer speakers, etc. when there's a cell phone in the vicinity. And it doesn't have to be right next to the device or speaker either. Makes you wonder whether the urban legends about brain cancer from cell phones aren't true...!

Try driving a few times without your cell phone in the car, or with it turned off. Try moving your cell phone to a different location when it's inside the car. See how that affects the presence, frequency, or intensity of the noise coming from the speaker.

 

EM interference from my phone was my first thought as well, but I've had the same phone since purchasing the car in November, and haven't had an issue until recently. Regardless, I tried a couple scenarios anyway.

Left the phone at home and went for a spin with the radio off. Got a small amount of chirping as I was driving away, and none when I returned.

Parked the car, went in got my phone, went back out to the car. No Chirping until I turned the radio on. Chirping. The sound persists after shutdown of the car and key removal so I thought radio off didn't matter, but maybe it needs to be on at shutdown to cause the chirping.

While the chirping was happening, I pulled my phone's battery, and the chirping continued for another 30 seconds or so with the phone dead.

Finally, I took the phone back inside well away from the car, and went back out. Started the car with the radio on and shut it back down. More chirping with the phone nowhere nearby.

So, it doesn't seem to be phone related. I've also noticed the noise in multiple geographic locations, so I'm not just parked next to some big emitter.

Damn electronic gremlins.

 

Hmm. That is odd. Never known cell phone EM interference to be so persistent...

Do you have a cell tower really close to your home...? That could be the source...

 

No, like I said, it does it regardless of where I am. Home, work, friends house. Doesn't seem to matter. But there also is not a cell tower near me.

 

I am betting that it isn't cell phone related now after all of your tests.

It might be worth going to the amp with the car off and pull and re-seat all the plugs going into it.

 

I had a bit of an epiphany in the shower this morning (where else do good ideas come from?).

I recently installed one of those "Snapshot by Progressive" units in the car. It uses the cell network and is also directly wired into the harness of the vehicle, and it transmits at the beginning and end of a trip to log it.

I'm thinking this is the culprit. I've only got a bit longer before the initial 30-day recording period is over, then I'm pulling it. I'm not dealing with this buzzing for another 6 months.

 

Yeah, that may be it. The sound definitely sounds like something related to a cell phone transmitter; those Progressive 'nanny sniffers' could very well be using cell technology to communicate information to their collection office...

 

Oh, I know they use cell signals. I'm 99% sure it's the problem. Cell interference fits the symptoms, and the timing fits the snapshot device. 10 days left in the initial collection time period then this thing gets pulled and shipped back. I'm not keeping it another 6 months for the full collection if it's going to do this all the time.