Sudden entertainment system full volume, only stopped by turning off car

[jcgraff]

Posting here to see if other 2015 Genesis Sedan owners have had this problem and found a solution.

Since purchase of the vehicle used a year ago (after my 2013 Genesis Sedan was totaled in a wreck), the audio unpredictably goes to full volume and cannot be controlled by the volume knob. It may only do it once or twice weekly. The only way to gain control of the volume I’ve found is to pull over and turn off the car.

I generally use BlueTooth rather than wired music input into the entertainment system. I changed phones in the last 2 weeks and setting up a new BlueTooth connection with the car did not eliminate the problem.

I have not yet tried using a wired connection for music, but prefer not to do so.

I am wondering if others have had this problem and whether it might be a problem with the pre-amp or amp of the entertainment system, or the car’s Bluetooth module.

I replaced the car’s battery a few months ago for other reasons, which one might think would reset the whole entertainment system, without an effect on the volume issue.

Thanks for any input.

 

[jcgraff]

I talked further with my son about the issue.

He does not use BlueTooth to connect to the head unit. He only uses a wired input via the USB cord in his car and does so because it is required to use the USB input for music to use CarPlay. He cannot recall whether it was an issue before CarPlay. He got the car 10 months ago and updated the firmware and map software almost immediately, and that added CarPlay

When it happens, the volume suddenly goes to very loud. He played me the comparable volume and it was 100dB using my Apple Watch. When it happens, the volume slider doesn’t show a change in volume setting. All the speakers become louder. He says it sounds like a lot of the mid-range drops out. Turning the volume knob down does reduce the volume, but a much lower setting than normal is required for listening level to be comfortable. After it happens, a volume setting of 1 or 2 would be normal listening level, whereas a normal volume level setting for him would be 20.

It happened with both his old iPhone 12 and his new in the last week iPhone 15 Pro (that is USB-C out to USB-A).

Unplugging the phone and plugging it back in does not correct the sound level issue.

Turning off the headunit power button and turning it back on did not fix it.

Switching to FM did not fix the issue, or switching back to USB input.

Pulling off the road and turning off the car then immediately turning it back on did not fix the audio issue. So, he usually just turns the volume down to 1 or 2 and lives with it until he gets where he‘s going. He’s gotten home from a drive, unloaded his car, and restarted the car and the audio issue was resolved.

Importantly, he once switched from USB input to FM after the issue started, and the volume stayed high with the same loss of mid-frequencies.

He has not tried using an analog out AUX cord from the phone to the head unit or BlueTooth, but since the problem persisted with switching to FM, it is unlikely to be from CarPlay, USB cable or USB input, or an issue with the DAC (digital analog converter).

It makes me think about a problem with a pre-amp, if there’s a discrete one in this system.

Any ideas on how to further diagnose or address this issue short of replacing a head unit?

Does someone specialize in repairing the headunits?