No sound from JBL audio system

A couple of days ago, I noticed the sound went out on my entire audio system. All the functions work, and I can switch between AM/FM radio, CD changer, Sirius, lockpicked video, etc., but the volume controls don't work in any of those modes. When I press the volume controls on the steering wheel or use the knob under the MFD, the volume level (on the MFD) doesn't appear. Sound from other sources work fine (voice commands, navigation, bluetooth phone, etc.) and those respond to the volume controls appropriately. Video also plays on the MFD as expected.

The only thing different lately is that I've plugged my iPhone into the AUX jack a few times over the past week (which worked fine). Other than that, everything has worked perfectly since I got the car and had the modifications installed almost three years ago.

I've attached the diagnostic screens from LAN Monitor. Anyone know what they mean or have an idea what's going on?

Thanks in advance,
Paul

 

I just happened to take my car in today to have a friend look at it. After an afternoon of investigating, we suspect the problem is with the head unit. We going to try exchanging it with a different one to see if that works, but at this point we're keeping our fingers crossed and hoping that'll do it. From the best that we could tell, it doesn't seem like any of my mods are involved or at fault. Have you made any modifications to yours?

 

Thanks for your input. I actually saw your thread before I posted mine. When you were having your problems, could you hear navigation instructions or audio from bluetooth? If you tried adjusting the volume, did you see the volume setting on the MFD change accordingly?

When my friend and I tried to troubleshoot my problem, we literally took the car apart. We took the amp apart to look for obvious meltdown on the circuit board, but there was none. Nav instructions and bluetooth still work as does the beep when you press buttons, and after reviewing the wiring diagram, we suspect that the amp needs to be functional for those to still work. As for volume controls, I can adjust them either from the steering wheel or the knob on the dash, but the volume setting doesn't display on the MFD. We're not certain, but we suspect it's something inside the head unit.

As for ruling out a loose connection, we completely disconnected the amp, MFD, and head unit during our troubleshooting, put the whole thing back together again, and the problem still persists.

I'm planning on calling tomorrow to see if my unit is under warranty, and my friend is checking a place that may be able to do a diagnostic on the head unit.

Keeping my fingers crossed...

 

It's funny that you mentioned this. With all the mods I did to my sound system I never had any problems. Recently however, I started listening to internet streaming radio on my iPhone via the car's built-in AUX port (no more than a few times at the most). Then one day I got in the car, and that was it--no sound (no high pitched noise either).

I've obviously since stopped using my iPhone with the AUX port, and although this happened a couple of weeks ago, I also noticed an anomaly with the Smart Key System last night. I was pulling up to a hotel to pick up a colleague in my car. I stopped the car (left it in gear with my foot on the brake), he got in, closed the door, and upon closing the door, a warning light comes on telling me the key isn't in the car. I ignored it and continued driving to my destination, and it's been fine since (i.e. the trip home). Hopefully it's a one-time thing, but when you told me your experience with your SKS, it got me thinking.

I just called and found out that my car is still under warranty. I'll keep the forum posted as things develop.

 

I'm still waiting to bring my car in to have my stereo repaired. (The delay is more logistics than anything else.) Strangely, my stereo seems to work intermittently for up to about a minute or two when I try turning it on--usually during the first ride of the day. I turn it on and it plays normally, but soon afterwards, the sound starts to cut in and out and the the audio completely dies again. I'm hoping to bring it in this weekend to get it fixed once and for all.

 

A quick update: I just had my car's stereo replaced yesterday (under warranty), and everything seems to work fine again.