DnSteele22

Hello Everyone!

I'm experiencing some nagging issues regarding my radio and navigation systems that I'm hoping someone on here can help me resolve. My car is a 2014 Audi A4 B8 with 110k miles. At times, the radio will not output any sound for weeks at a time and then one day, it decides to work and will work for several weeks before it decides to quit on me again. I'm not sure what could be causing this...if it works when I start the car, it will work that entire trip...but if the radio doesn't come on upon starting my car, then it will not work mid-trip. It either works or it doesn't...it's not like it turns on/off while I'm driving mid-trip. When the radio doesn't output sound, I can still connect a bluetooth device to the MMI but it also does not output sound. Additionally, I can still direct the car with my voice like "Enter address" or "Call XXX", but I can' hear the person on the other end, but they can hear me. I can still navigate all the menus of the MMI just fine and the navigation system still displays directions, the MMI/radio is always powered on and displays correctly. Also, regardless of whether the radio sound is working or not, the turn-by-turn audio directions will never output any sound. I'm sure these two issues are related somehow...does the lady's voice have her own dedicated speaker or does it come through all of them like the radio would? It's weird this function doesn't work even when the radio decides to work correctly. I know this is hard to follow but in summary: the lady's voice that provides the turn-by-turn directions does not output at all, and the radio will output sound for several weeks at a time before ceasing to work again. So, the radio works at times, but when this issue first arose the lady's voice stopped working and has ever since.

Things I have troubleshot so far: I have confirmed the lady's voice isn't muted or too low, I have unplugged all the connections and re-plugged on the amplifier in the trunk's read driver side, I have confirmed my battery is good with autozone's tester, I have held the (3) buttons down on the MMI to restart it, I have performed a factory reset in the MMI menus. My car isn't throwing any OBD codes, this is clear.

I am pretty handy and have resolved issues similar to this that I want to try and fix first before paying a ton of money...I'm just not sure where to go on this one to troubleshoot it next. I appreciate any and all help and guidance! Please let me know if you need me to follow up on something or provide more details/information!

Thanks,
Dan

SMac770

Clarify the configuration some.
Is this an Audi concert or Audi multimedia (MMI 3G+ for US MY14) vehicle? What's the label on the unit above the climate controls. - sounds like MMI 3G+
Is this a standard sound system or B&O sound system vehicle? Do you have the round rings on the front door sail panels that say Bang & Olufsen? Such as https://i.ebayimg.com/images/g/wB0AA...6y/s-l1600.jpg
Because with MMI 3G+ and standard, there is no outboard amp, just the radio unit with integrated amp, in the left rear. With B&O, there's always the separate amp unit (with the heatsink fins).

DnSteele22

Hi SMac! Thanks for the quick response! I have the 3G version and I do not have the Bang and Olufsen sound system.

SMac770

So with MMI 3G and not B&O, you'll just have the radio unit (with integrated amp) in the left rear, no J525 outboard amp (object with heatsink fins on top).
I'd be more interested in a full scan with VCDS when the issue was live. Are you using VCDS or just a generic OBD-II scanner (which may or may not interrogate infotainment units)?
If the MMI system is operating, then the MOST ring is up, meaning all the ring members have power and are operating at a basic level.
Best guess is it's an amp issue inside the radio unit, but what manner of issue I have no idea.
The MMI has so many volume settings in the green menu; have you checked those to see if any have been moved out of reasonable range?

DnSteele22

Hi SMac, thank you again for assisting here. So, I used a plain-jane OBD tool from Autozone to scan my car for any possible codes even though I had no check engine light on...the car was also scanned during a time when the radio was functioning. I do not have access to a VCDS and the price is very high, but I am willing to do this if you know of any resource to scan with VCDS for free. I'm not familiar with the MOST acronym or what ring members are...I'm assuming the MOST ring is the system that powers the speakers and ring members = speakers? I checked all the volume settings in the MMI and the green menu, and everything checks out fine there, thank you for that suggestion.

I have removed the amp from the rear trunk before. I wonder if there is a way to test it with a multi-meter? Also, I can buy that unit for like $20 from a local junkyard here...I'd be willing to swap the unit out as a stab to fix the problem, that would be $20 well spent, even if it doesn't work. Do you know if it's just a simple plug and play replacement or do I have to code the car or something to let it know I've replaced that unit?

Thanks!!!

SMac770

MOST = media oriented system transport or something like that, it's fiber optic ring that MMI uses. So if a unit is down, it takes the whole ring down, as the ring "passes through" each device on the ring. This is the ring that passes the audio signals between devices. It's the "front end", not the back end with the amplification and speakers. Though without the B&O amp, the "front end" in your car is nothing more than the J533 (what the OBD-II port talks to) inside the dash, the J794 (the MMI main module) in the dash above the climate controls, and the radio unit (with integrated amp channels) in the right rear.

Yeah, an OBD-II scanner is not going to be much use for stuff outside the engine/transmission/ABS. VCDS is $200, which is more than worth it if you're owning a VAG product (VW Automotive Group), imo. But if that's still high, at least an OBDeleven would let you scan and clear DTCs and read some values and do some basics like service interval reset for cheaper.

https://obdeleven.com/en/home/187-st...&id_currency=3
There's just no reason for an Audi owner to not have at least this level of functionality, for only $62. Note, it's not like VCDS, which requires Windows. OBDeleven is a mobile app, you need an android or iOS device to run the app; the device connects via Bluetooth. Do not leave the device plugged into the OBD port when you're not using it; throw it in the glove box.

If you can get a replacement radio unit for $20 to try, go for it. Normally would be at least 10x that on eBay. You'd want to code it to make sure it's configured the same (ie, use internal amp channels or use external amp), but you can't do that without VCDS of the PRO subscription for OBDeleven. Either way, you'll end up having to pay a dealership or capable shop an hour labor (or whatever they charge minimal for a 10 minute task) to reset the component protection. If the radio came from another B8.5 vehicle which also did not have B&O, the coding should be fine as is. From a B&O vehicle, the coding would need to be changed to what yours has currently (you can see the coding in a scan, at least in VCDS).

But the component protection would only disrupt playback from entertainment sources. You'd know if anything had improved if you could now get the navigation audio or the Bluetooth handsfree audio.

DnSteele22

Hi SMac,

Quick update: I've made an appointment with a local shop on 12/22/22 to perform a full blown VAG-COM diagnosis. Once I get the results, I'll communicate them on this thread. I haven't been able to replace the radio unit yet, the $20 one I found from the junkyard was not available, so back to square one on that front.

DnSteele22

Hello SMac and everyone!

I wanted to share the solution to my particular problem. No diagnostic codes were found however upon replacing the amplifier in the trunk, all the issues were resolved! A faulty amplifier caused the intermittent radio audio. A special thank you to SMac for assisting me and helping me fix this issue...much, much appreciated!!!!

WalkerMichiganRanger

I am having a problem with an echo in the radio of my 2015 A4 radio. I have tried turning off the "GALA" function but it doesn't make any difference. Does anyone have any suggestions? Thanks, I appreciate it.