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Discussion Starter · #1 ·
I have spent most of the morning reading and searching here. Have a '19 Elite and have gotten the no audio connection issue come up maybe 5-10 times since we have owned the van, purchased new in 2018. Most recently was over the weekend. Similar to what some others have described, on a road trip, warm outside (between Houston and Dallas), on the highway, hit some stop and go traffic. When I stopped, engine shut off and kicked back on a minute later when I left off the brake and got the no audio error. Have a small USB keyboard that we tried rebooting the system a couple times to no avail. At the next stop, I shut it off, opened door, closed and restarted. Still nothing. The RES with headphones was working fine the whole time. I had forgotten how to get into diagnostic mode to see what was going on at the time. When we got home, waited 5 mins, turned on the van and all worked as normal. It hasn't happened since then. It happened some last summer, always really hot out and IIRC it was mostly after an idle stop. I don't have crackling/popping or any of the symptoms of the MOST connector. Truthfully (thankfully), this no audio thing is the only real issue we have seen with our van.

I have seen the post with the amp being red in diagnostic screen for folks. My thought is that the amp is overheating and when idle stop or any start action occurs, the amp has already let the head unit know it is too hot, and that state change (starting engine) causes the infotainment to shut down the amp to prevent damage. This makes sense as to why a software fix has not been implemented in the last 3 years because it is a hardware issue. They could change the threshold, but if it is overheating, it is overheating and they don't want it to burn itself up.

I have read a couple things about amp locations which is why I am posting. I want to know where the elite amp is located. Is it really behind a panel in the back of the van or is it up under the dash somewhere? Are there actually two of them or is it just the one?

My plan is to wire up a fan mounted above the amp that will blow air over it to hopefully aid in cooling it to see if my hypothesis is true. In the meantime, if it happens again, I will be sure to go into diagnostics to see what is happening.
 

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On my van i too noticed this issue is exclusively when it is Hot outside & when the stop/start system activates for a really short time (i.e. it shuts off moments before green light and starts up again right away)

Since i started disabling start/stop every drive, i have not had the no audio issue. But summer is just beginning so we shall see

Every time i have gone to diagnose screen the amp has been red like you describe, I think the stop/start is surging / low voltage-ing the amplifier and its locking itself down to protect itself.
 

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Discussion Starter · #3 ·
Thanks for the response.

I have purchased a digital temperature controller. My plan is to install it in the center console and monitor the temp the amp gets while driving around town. If by some chance it exhibits this behavior, I will know at what temp the amp is when it happens. This controller I can set a temp to kick on the silent 12v fans I also purchased. My goal is to know if this is the issue. If so, I will put everything behind the panel, powering it from the 12v socket back there and the whole thing will be out of sight out of mind, with the fans kicking on at say 125-135 degrees or so, unless I need to make it lower. Just need to figure out if the amp is overheating and that is the ultimate problem.
 

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I personally doubt the amp itself is over heating, as i said before, i think its a voltage issue (spike / drop)

I think Amp is under the trunk side panels, I wonder if a 12v stereo capacitor would help it survive the cycling

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Discussion Starter · #5 ·
I personally doubt the amp itself is over heating, as i said before, i think its a voltage issue (spike / drop)
I guess I just don't get that if this is in fact the case, why it only happens when it is really hot out. Also, if it were a voltage issue that caused it, why would a "hard restart" of the system by shutting the van off, opening and closing drivers' door and then restarting not fix it, especially if it continues the same behavior for several minutes after parking in the shade.

Yesterday, as it was 103* out and after driving around for an hour or so, the conditions were met and it idle stopped when we were close to home. Sure enough, loss of audio when it came back on. When I got home, I went into diag screen and found some interesting stuff. First, this is one I have seen a picture of before here, the amplifier showing red:
Gadget Font Display device Rectangle Electronic device


If you click on the amplifier, you get this:
Communication Device Gadget Mobile device Audio equipment Electronic device


Last one I took a pic of was a hardware auto-detect:
Audio equipment Gadget Technology Display device Font


I tried to click apply on this screen, it reboots the system, but got the same thing. I again shut the van off, opened and closed the door and started it back up. Everything remained the same with nothing working. I waited 10 minutes and tried again and everything came right back up. Amplifier showed up green and this last screen, it was green as well and there was no check mark there. Another screen I found showed the max/min temperatures for the system and it was 32* and 168.8*. I will be working on my temp controlled fan setup within the next week and will post results.
 

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the only way I have gotten system back online was shutdown, get out and take key away then come back and restart.

My theory about the voltage spike is just thats most common during startups, and if a stop&start are too close together it could make that worse.
Maybe it has a digitally set lock down that has some amount of time to recover or maybe im totally wrong and it is thermal.
 

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Discussion Starter · #7 ·
Yeah, I think the voltage spike plays a part in it, I just think that perhaps the amp has thrown up a flag that it is overheated and that spike is what causes the system to check itself and the amp then goes offline. I bench tested my fan setup last night, so now I just need to get that rear panel open to install it. Will post progress of how it goes. If nothing else, I can confirm just how hot the amp is getting.
 

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Yeah, I think the voltage spike plays a part in it, I just think that perhaps the amp has thrown up a flag that it is overheated and that spike is what causes the system to check itself and the amp then goes offline. I bench tested my fan setup last night, so now I just need to get that rear panel open to install it. Will post progress of how it goes. If nothing else, I can confirm just how hot the amp is getting.
Very interesting theory. I think you may be onto something. Thank you for your efforts. Please keep us posted on your findings.
 

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Discussion Starter · #10 ·
Ok, got the initial work done to monitor. It isn't pretty, but I will be able to monitor the amp temperature and see if this is in fact the cause of the issue. If it is not, I have not cut or spliced into, so I am all good there.

Popped the rear panel off to get a good look at the amp. The big heatsinks for the amp are on the bottom, making me thing it is mounted upside down, which seems a bit odd, would think you would want the big heatsinks at the top to dissipate the heat.
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I flipped it up and put the temp sensor between two of the ridges on top, figure that is the hottest part of the amp. Then zip tied around the whole thing to help prevent it from falling out of place:
Wood Electrical wiring Line Audio equipment Bumper

Then I fabbed up a little fan mount out of some thin aluminum I had and mounted the fan pointing at the side of the amp:
Hood Grille Motor vehicle Automotive exterior Gas

Finally, put it all back in place, ran the wires in split loom up to the center console and left one wire with a 12V outlet plug that I ran up and plugged in the trunk:
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I checked the temp of the amp with a non-contact thermometer (actually 2 of them that I had) and each was within a degree or two of the controller I got, so I feel it is working well. I currently set the fan turn on temp at 170 just to see how hot it is actually getting. If I can get it to where the amp shuts down, I will turn the fan temp down a little ways below that and see if this prevents it.

I can say that sitting in the garage with ambient air temp of 90* and that rear panel open, the amp was up to 110* within a few minutes of having the radio on. Will post up once I have some data to share.
 

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I also had this problem in June/July last year on long road trips when it was hot (90+). Originally no dealer could diagnose because it was not doing it when I took the car in. I took pictures of the diagnostics screen. On the way back home and just short of 36,000 mile warrant expiration, it did it and I stopped at the dealer while sound was off. It took about 20 minutes to get checked in and someone to come out and check the car. Sound was working parked that long in the shade! I showed the service manager my pictures and emailed them to him. He called later in the day and said American Honda already got back to him and he ordered the parts and it would be covered under warranty. Unfortunately, with pandemic supply chain and chip shortage iIt took 2 months for the parts to come in. This has been a complete fix.

Turns out you all have the same problem and the relevant link has been in the forum for almost a year now. TSB 21-013 - Warranty Extension: 2018-20 Odyssey MOST Bus Network Connectors

From TSB 21-013:

BACKGROUND
A loose connection in the MOST bus network is causing a popping or crackling from the speakers or no sound from the audio system. There may also be a Network Loss message and/or display issues. American Honda is extending the warranty for the MOST bus network connectors on these vehicles to 5 years or 60,000 miles from the original date of purchase, whichever comes first.

CORRECTIVE ACTION
Install the FAKRA connector set

I never got a notification from Honda on this issue! Service manager explained the original "MOST" connectors expanded from heat and lost connection with the amplifier for sound output. New connectors do not have that problem so it was all due to bad bus connectors.
 

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Discussion Starter · #13 ·
The engineer in me says to run the system without the fan at all first to set the baseline temp reading. Then start fan testing.
Looking forward to what you learn either way though.
Also being an engineer, I had the same thought! (y) I did set the turn on temp very high (170) and yesterday was the first chance that I got to really watch it. About a 30 minute drive, sit for another 30 minutes (ironically this was to look at this van's potential replacement), and then 30 minutes on the way home. Temp just slowly crept up while driving. The warmest it got was right when we got home, it hit 131*. Since I was home and not going anywhere after that, I went ahead and changed the temp setting down to 125* and the fan kicked on. Within 2 minutes, it was down to 128* so I know that the fan is strong enough to lower the temp. I then turned the temp back up and hopefully in the near future I will get it out in the heat more to see when this really happens. My hope is to get it to have the failure, note the temperature at the time, kick the fan on and keep driving to see if the fan stops it from happening again. If it does, I have a good idea of the temp to set it at to prevent it from getting that hot where it shuts down.

Turns out you all have the same problem and the relevant link has been in the forum for almost a year now
I have read quite a lot about the MOST bus connectors. Pretty much everything I have read pointed to the fact that you would have speakers crackling if you were experiencing issues with it. Also, the same issue has been occurring in Pilot's as well and I found folks in this thread who had the MOST bus connectors changed per that TSB and still have the same No Audio Connection issue: Honda Pilot 2020 No Audio Connection
 

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Also being an engineer, I had the same thought! (y) I did set the turn on temp very high (170) and yesterday was the first chance that I got to really watch it. About a 30 minute drive, sit for another 30 minutes (ironically this was to look at this van's potential replacement), and then 30 minutes on the way home. Temp just slowly crept up while driving. The warmest it got was right when we got home, it hit 131*. Since I was home and not going anywhere after that, I went ahead and changed the temp setting down to 125* and the fan kicked on. Within 2 minutes, it was down to 128* so I know that the fan is strong enough to lower the temp. I then turned the temp back up and hopefully in the near future I will get it out in the heat more to see when this really happens. My hope is to get it to have the failure, note the temperature at the time, kick the fan on and keep driving to see if the fan stops it from happening again. If it does, I have a good idea of the temp to set it at to prevent it from getting that hot where it shuts down.
Did the start/stop system engage during any of those drives? or do you disable that?
 

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Discussion Starter · #15 ·
When I got home, I turned off the HVAC to force it into start/stop. I did get it to start/stop in the driveway at 130* amp temp and it did not kick off. So I assume if this is the problem, the shut off temp is higher than that.
 

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Discussion Starter · #16 ·
Well, bad news for my theory today. Outside temp upper 90's. Drove half an hour to a store, it was there for an hour out in the sun, then half an hour back home. The amp had gotten up to 128* when I stopped for gas close to home. When I started the van up, no audio connection. Let it sit there and adjusted the temp down to 120 and it kicked the fan on. It dropped to 125* a mile down the road at a stop light. I shut the van off, opened the door and restarted, still no audio connection. Tried once more a minute later at home and still nothing. 10 minutes after the van sitting in the garage (temp down to 115*), back to normal. I had checked diag screen when I got home and same as before, only the amp was red. Current plan is to leave the temp setting at 120 and just see how it does.
 

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Discussion Starter · #18 ·
Ok, got more of a long term test. Put just under 3k miles on the van over the past 10 days. TX -> MN -> SD -> TX. There were 5 days of 4+ hour drives, a couple were 10 hours. Today was the hottest day, with 5 hours of 100+ degree heat. I had set the temp on the controller to 120* and just left it there, coiled up in the back seat. The good news is, I never had the issue once. No way for me to definitively say my amp cooler was the reason, but I feel relatively confident it would have shut off at some point without it on this trip.

The odd thing is, when we got home at the end of the day today, I had my son check it and it was 132*. I got it to auto start stop and it didn't kick the amp off. This was after 5 straight hours in 100* + weather. A new thought is that maybe the part that is overheating is somewhere on the bottom and this fan being on it when the top of the amp gets over 120 is helping it. Regardless, will leave this in place the rest of the summer (or as long as we have the van) to see if the problem returns with the temp set at 120.
 

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UPDATE: I have been on a cross country road trip driving up to 8 hours a day in bright sun and 95+ temps and about 3000 miles so far. I can tell the naysayers the TSB 21-013 fix completely fixed my audio problem. Not a single drop-out since the work to replace the FAKRA connector set was done.
 

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Discussion Starter · #20 ·
I can tell the naysayers the TSB 21-013 fix completely fixed my audio problem.
I never said it couldn't fix it, but I can definitely point you to people who have had that TSB done and still experienced the same problem after having it done. All I am saying is there is no guarantee that the TSB fixes it. Hopefully yours maintains it, but I would like to know if they did anything else (software update maybe) at the same time that might have changed something else as well.
 
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