Help troubleshooting e82 (or e9x) BMW radio/audio issues
 

Another day, another random electronic gremlin on a BMW. This is on my premium audio system with BMW professional head unit on my 2009 e82. Should be very similar to e90x systems.

Symptoms/troubleshooting findings so far:
- no audio from radio, aux, CD, etc.
- no door chimes
- no SOS malfunction error code
- MOST optical loop is intact (the diagnostic port under driver footwell is lit)
- when I turn up the head unit volume to max, I can hear audio from the radio and door chimes very faintly, which leads me to believe the audio signal is intact just not amplified.

I checked connectors going to amp and out of the head unit, no issues there.

I am leaning towards an issue of the amplifier since I can hear the correct sounds when I crank up the head unit. Also because it affects the door chime as well, which would not be the case (I think) if it was a head unit issue.

I took it out and opened it up, didn't see any obvious signs of damage on the circuitry.

Another possibility I've read is that the battery is low and so it's going into a power conservation mode, but I don't know how to confirm this. I have noticed in the past year I would get battery warnings when I would leave the car on too long without the engine running, but have not experienced it since this sound issue.

Anybody know how I could diagnose the amp or battery short of buying a new one to try? Or if anybody has come across this problem?

i can scan it with protool if you drive to surrey. Maybe it will find some errors and it might point you in the right direction.

I had battery issues with my E90 every winter and never had this happen.

Turn the dipstick clockwise 4 times then counter clockwise twice. Tap the brakes then open the gas cap. With the gas cap open, wiggle the passenger side windshield wiper. Close the gas cap after that and you should be GTG.

^lol

This thread makes me want a BMW again even MORE!

Not.

If you suspect your battery, go get a multimeter for $10-$20 and test it. cheaper than a new battery and if you wrench on cars and ever need to chase electrical issues you definitely should have a multimeter. It's not a tool you need every day but will pay for itself many times over if you have one.

Did you throw a code reader on it to see if there are any codes?

No I haven't done either yet, but good call.

Is the battery voltage on BMW's similar to other cars? i.e. 12.6v range?

I have a generic OBD2 reader not BMW specific (Carly), wasn't sure if it would register codes for radio issues, figured it was just engine codes, but I'll give it a try.

check in the drivers side above the pedals for loose connectors, i rmb someone was working on my E92, somewhere in the steering column/footwell area and disconnected something in there rendering no sound/chime/warning at all until i brought it back and had them double check. next is to check there is actually power going to the amp in the trunk. even tho u have the optical light that u see, the amp may still not be powered up. the professional amp should have a 2 pin plug for 12V/ground only.

yup, same power as any other car.

Generic code readers will pull some codes but not all. I finally caved and invested a couple hundred bucks on a Foxwell NT510 to be able to read and clear BMW specific codes that the generic wouldn't pick up. I'm in Pemberton but am in Vancouver to visit my family when public health orders allow it. If you don't resolve this issue in a couple of weeks, I'm happy to bring it with me and lend it to you when I'm down there next, so you don't have to drop a couple hundo on buying one. PM me anytime.

Thanks for the offer and helpful info, I will keep that in mind!

Ok, so I used the BMW secret menu to check battery voltage.

In accessory mode when cold it's down to 11.5v. engine on is at 14.5v. so seems like regardless of radio, the battery likely needs replacing according to the voltage. After running on idle for a few minutes and kept off for a few minutes goes back down to 11.6v.

No stored or active codes with the obd scan.

I had same issue with my 2012 E82 with Professional unit as well and wasn't able to pin point a solution while I had the car.

I don't listen to radio, just USB mp3 music, but the radio has gone out, no sound.
the only fix for me was to take out usb drive, turn off car and back on

I do not how to resolve if the radio goes out as I don't listen to the radio.

You can try INPA and other software by going to https://www.bimmergeeks.net/downloads
I would advice to use at your own risk. Eg a computer that has nothing but the tool on and you do not mind reformatting if you have to. And make sure it does not have access to your network. Always take precaution with 3rd party software.

But the ultimate fix for me was to get rid of the car.

That voltage is low for a car left off for a short while. At least your alternator is good. How old is the battery? The battery issue may be tangential to the audio issue but I’d think about a new battery. I’m pretty sure an E82 chassis will need the battery programmed to your car.

My X4 F26 had a similiar issue with the Harmon Kardon audio, no audible sound from the speakers and no door chime's. Replaced the HK amp and all was restored cost a couple of grand. BMW = Break My Wallet

$200 gamble at the price gougers at Affordable Auto Parts later, stereo is fixed. It was the amp!

Thanks for those who helped troubleshoot!