[bslenter]

We have a 2.0 Touring purchased late December with 6000 miles. Today we took a 1-1/2 hour drive to visit family. No issues on the drive out. I used ACC and LKAS most of the way. When we got in the car to head home, after starting the car I received a series of "see your dealer" warning messages on the left gauge and most of the convenience and safety features were disabled. Shutting off the engine then restarting did not clear the problems. They all popped back up same as before.

The following systems had orange warning messages and were disabled:

• CMBS
• LKAS
• Blind Spot
• Auto High beam

There may have been one or two others, but I did not make a note of them.

Also, the following functions did not work:

• Turn signals (!)
• Backup camera
• Trunk release (trunk button, driver door button, and remote did not open it - pressing the trunk button caused a beep but the latch did not release)
• HUD (it was completely off)

As far as I could see, ACC was still enabled because the ACC indicator was green (the LKAS indicator was orange, however). But I did not attempt to use it.

I was concerned about being stuck far from home, so I decided to get on the freeway and see if we could make it home without any further issues. The car drove completely fine. The systems remained offline for the entire drive. Not having turn signals was a little unnerving.

Once I got us home, I decided to pull a battery cable to see if this would reset things. This worked. After starting the car back up, the system took about 5 minutes to go through a "re-initialization" which was indicated on the display (message: "System Initializing - Keep Driving"). I took it for a drive and within a few minutes, everything was completely back to normal.

I've seen posts with similar issues described, but in those other accounts I've noted some differences. Usually the ACC gets disabled, where in my case it did not. For some, they only get a CMBS error, while I got the full suite. I'm the only one who described losing the turn signals or the trunk latch.

We've been really enjoying our new car, other than a few infotainment glitches which diminished with the recent software update, and the HUD squeaking noise, which we will eventually get addressed once the dealers figure out a reliable way to do it. But this failure this evening has us a bit unnerved. For one thing, it's a little startling to learn just how many car systems are able to fail together (the turn signals!?!). Also, I don't want a vehicle that has to be treated like a 2008 Blackberry smartphone (pull the battery every month to clear glitches). Though I did put a 10mm wrench in the glove box just in case I do need to reset it again.

I'm finding out this is not unique to Honda -- luxury cars with these advanced features are having more of these types of issues too. But I'm sure hoping to not see much more of this.

I'm debating whether to bring it in to the dealer tomorrow, or wait to see if it happens again. Since I reset the problem (and likely any error codes by pulling the battery), they probably won't find anything.

Anyone run into a scenario like mine?

 

[ObsidianBlu2T]

Anyone run into a scenario like mine?

That is really unnerving since I have the same Touring trim at around 3500 miles, and crazy that the turn signals did not work due to the instability! I'm sure you have the latest headunit update from the other thread, but hopefully/luckily things can be updated OVA for stability whenever Honda releases them.

Knock on wood, I still have not experienced any glitches pertaining to the advanced safety systems at all on my Touring 2.0T, with everything turned on from daily use. My first reaction to this scenario would also be to pull the battery connection. Good to know that the car displays "System Initializing - Keep Driving", somewhat assuring that the car is actively running through internal checks / resets / services.

 

[cjohnstone]

Please come back and let us know what they find!

 

[2018TwoPointOh]

Sorry to hear you're having to deal with this. If this happens again closer to home, definitely take it to the dealer before pulling the battery cable. I bet they wouldn't find anything wrong with the car at this point, although it wouldn't hurt to have the issue documented in case it happens again.

 

[RickBlaine]

This is the thread you no doubt reviewed before posting:

http://www.driveaccord.net/forums/2...2018-intake-hose-clamp-came-loose-factory-not-bad-maf-gas-nor-transmission.html

Indeed, you are correct in that no one mentioned turn signals going out, back up camera out, and trunk release out. I want to add that I have followed several of your posts, and you are perhaps one of the most thorough writers on DriveAccord. YOU would mention these "minor" things if your engine went into "limp" or "safe" mode- whereas most of us would ignore posting info about the trunk release if the engine shuts down. This may explain why you think your situation is different.

I am thinking it may have been a loose hose, as mentioned in that other, definitive thread- as well as in many car forums representing all makes/models with turbo engines. I also note posts from @Miker about weird stuff happening if the battery is failing or if battery connections are not tight and clean.

Lastly, I would have LOVED to know the codes that popped up- but you erased them when you re-set the battery. I would have liked to know if you got the generic Mass Air Flow (MAF) sensor code that so many dealers are saying the problem is- and of course that is NOT the problem, it is one of the loose "turbo" hoses as outlined by @zroger73 in post #132 of that thread.

A cheap OBDII code reader can be had for $15 on Amazon or eBay. Would be a good investment. Or, if you are in the United States of America, you can stop by any Advance Auto, Pep Boys, Autozone, NAPA, etc for a "no appointment" free code scan.

If your issue turns out to be a loose hose connection, this thread will probably be merged into the existing one.

 

[bslenter]

This is the thread you no doubt reviewed before posting:

http://www.driveaccord.net/forums/2...2018-intake-hose-clamp-came-loose-factory-not-bad-maf-gas-nor-transmission.html

Indeed, you are correct in that no one mentioned turn signals going out, back up camera out, and trunk release out. I want to add that I have followed several of your posts, and you are perhaps one of the most thorough writers on DriveAccord. YOU would mention these "minor" things if your engine went into "limp" or "safe" mode- whereas most of us would ignore posting info about the trunk release if the engine shuts down. This may explain why you think your situation is different.

I am thinking it may have been a loose hose, as mentioned in that other, definitive thread- as well as in many car forums representing all makes/models with turbo engines. I also note posts from @Miker about weird stuff happening if the battery is failing or if battery connections are not tight and clean.

Lastly, I would have LOVED to know the codes that popped up- but you erased them when you re-set the battery. I would have liked to know if you got the generic Mass Air Flow (MAF) sensor code that so many dealers are saying the problem is- and of course that is NOT the problem, it is one of the loose "turbo" hoses as outlined by @zroger73 in post #132 of that thread.

A cheap OBDII code reader can be had for $15 on Amazon or eBay. Would be a good investment. Or, if you are in the United States of America, you can stop by any Advance Auto, Pep Boys, Autozone, NAPA, etc for a "no appointment" free code scan.

If your issue turns out to be a loose hose connection, this thread will probably be merged into the existing one.

I appreciate the compliment. I'm a civil engineer so it's in my nature to be thorough and detail-oriented, especially when trying to analyze a complex problem like this and share info with others.

Even though I used to work on my own cars back in the day, and am knowledgeable of computers and electronics, I still have a lot to learn about how these late model vehicles are set up. Even our 2008 Pilot was dirt-simple compared to the gadgetry in this Accord.

My working theory right now (a completely uninformed theory - I've never cracked open a repair manual for a vehicle like this) is that all the systems that failed are tied in to the same vehicle controller network, and the network went down, perhaps due to a random glitch or perhaps because one of the connected modules is faulty. Or perhaps the loose turbo hose trips a sensor on the network and faults everything out somehow.

I also got to wondering whether the turn signals might have been working after all, and just the dashboard indication and sound was disabled. We never got out to look at the rear taillights. But that's neither here nor there.

My wife took the car to the dealer a short time ago, and I sent her with a copy of the first part of my OP in this thread describing the issues in detail (I left out the part about comparing a modern Honda to pulling the battery on a Blackberry phone :wink). Hopefully they will give it a thorough look despite my clearing the codes. If not, I will certainly try to get it to a dealer with the active faults next time (if there is a next time, hopefully not though).

I definitely did not see the vehicle go into "limp" or "safe" mode last night. It drove just fine. After I reset the battery, I took the car for a drive and a couple of times I put it in Sport and hit WOT for a moment (got the right tire spinning a bit coming off the corner, too :grin). It performed perfectly and the errors did not come up. If the turbo hose was loose, I'd expect a problem to crop up. But I have been noticing seemingly unusual turbo noises the last few weeks, so who knows.

I'll report back after we hear from the dealer later today. They are also looking at the HUD squeak issue.

 

[II Kings 9:20]

Always think about a bad battery or an electrical glitch from the battery. Any time multiple codes are thrown and multiple systems fail it’s often battery and not all of the systems failing simultaneously. My Pacifica battery failed at 10 months and did the exact same thing as your Accord. Numerous similar reports across many brands.

 

[bslenter]

I just picked up the car from the dealer. They addressed both issues (systems failures and HUD squeaking). I only briefly drove the car (a couple miles to my house). The fixes are working so far.

The systems failure was caused by the “multiplex unit” (basically the equivalent of an Ethernet hub that networks all the systems together, as I suspected). He told me that even though I reset everything by pulling the battery cable, they took it for a drive and the failures happened again pretty quickly, so they were able to run diagnostics and isolate it to the multiplex unit.

He mentioned that, sometimes, they get a car in with a bad multiplex unit that only fails once in a while, and that’s much harder to diagnose. Glad we were not in that boat.

As for the HUD, the service rep told me that Honda has been having problems with “fit” of the HUD component, so they replaced the dash trim piece around the HUD and lined it with foam tape. When I left, the interior was pretty hot, and I didn’t hear any sounds, so we’re off to a good start. We’ll see if it holds.

We did have to leave it overnight so they could order the parts, but they handled everything quickly and professionally. Hopefully things go well from here on out.

 

[Shakedown]

What is the build date of your car. And you have the part number they used?

Can you advise us your location?

I just picked up the car from the dealer. They addressed both issues (systems failures and HUD squeaking). I only briefly drove the car (a couple miles to my house). The fixes are working so far.

The systems failure was caused by the “multiplex unit” (basically the equivalent of an Ethernet hub that networks all the systems together, as I suspected). He told me that even though I reset everything by pulling the battery cable, they took it for a drive and the failures happened again pretty quickly, so they were able to run diagnostics and isolate it to the multiplex unit.

He mentioned that, sometimes, they get a car in with a bad multiplex unit that only fails once in a while, and that’s much harder to diagnose. Glad we were not in that boat.

As for the HUD, the service rep told me that Honda has been having problems with “fit” of the HUD component, so they replaced the dash trim piece around the HUD and lined it with foam tape. When I left, the interior was pretty hot, and I didn’t hear any sounds, so we’re off to a good start. We’ll see if it holds.

We did have to leave it overnight so they could order the parts, but they handled everything quickly and professionally. Hopefully things go well from here on out.

 

[RickBlaine]

Each of you can update your UserCP to include your location under your username, like it is with me. This helps the forum and reduces clutter with "where are you" posts?

I will update thread title to include "multiplex" unit.

 

[bslenter]

I just updated my profile with location and also build month/year of the vehicle. I have one of the early 2.0s, purchased right after they started showing up on lots. Here's a snip of the service bill with the part numbers. Dealer was Folsom Lake Honda.

Edit: Why can’t I see my profile and signature in posts when viewed in the iOS Tapatalk app? I want to make sure others can see it.

 

[VWGTI]

I just updated my profile with location and also build month/year of the vehicle. I have one of the early 2.0s, purchased right after they started showing up on lots. Here's a snip of the service bill with the part numbers. Dealer was Folsom Lake Honda.

Edit: Why can’t I see my profile and signature in posts when viewed in the iOS Tapatalk app? I want to make sure others can see it.

Thanks for following up appreciate the info! Hopefully it's smooth sailing from here.

Sent from my SM-N910W8 using Tapatalk

 

[ZURV4N]

I registered just to comment. Thank you for such a comprehensive post, bslenter. I am having the exact same symptoms on a 2.0T Touring with just shy of 3,000 miles that I purchased back at the end of February. The warnings showed up earlier today when I started the car, exact same warnings as the OP, and the HUD is off. Restarting has no affect. I had missed that the turn signals weren't working, so I went and tested them - they work on the exterior, it's just the indicator on the dash that doesn't show them. I had also missed the trunk - it will not open for me either.

Two things I noticed that you may have just missed - the remote start will not work, and hitting the lock button twice on the FOB does not elicit a beep like it normally does.

I've got an appointment at the dealer where I purchased it tomorrow, hopefully it's as simple a fix for me as it was for you. Thanks again for the info.

 

[2018TwoPointOh]

It's a sad commentary on how crappy dealer service is, but I'm really impressed that they isolated the problem and repaired it. I thought sure it would be a new/obscure part needing replacement, but they've been using multiplex units for decades.

 

[bslenter]

I registered just to comment. Thank you for such a comprehensive post, bslenter. I am having the exact same symptoms on a 2.0T Touring with just shy of 3,000 miles that I purchased back at the end of February. The warnings showed up earlier today when I started the car, exact same warnings as the OP, and the HUD is off. Restarting has no affect. I had missed that the turn signals weren't working, so I went and tested them - they work on the exterior, it's just the indicator on the dash that doesn't show them. I had also missed the trunk - it will not open for me either.

Two things I noticed that you may have just missed - the remote start will not work, and hitting the lock button twice on the FOB does not elicit a beep like it normally does.

I've got an appointment at the dealer where I purchased it tomorrow, hopefully it's as simple a fix for me as it was for you. Thanks again for the info.

I’m glad my post helped. Avoid pulling the battery cable to reset the system. You’ll definitely want to leave it in the failed state so the dealer can diagnose it. I was fortunate that the failure repeated itself for the dealer so that they were able to isolate the problem. They told me that sometimes a bad multiplex unit fails infrequently, which makes it very hard for them. And as you know, a dealer usually won’t do a warranty repair based on the customer’s word.

Good luck tomorrow.


Sent from my iPhone using Tapatalk

 

[ZURV4N]

Good luck tomorrow.

Unfortunately it doesn't look good. All they did was do a "hard reset", and called to let me know the issue is cleared (after having my car for four hours). Which is essentially what you did before it came back. This is after I even directed them to this thread. So if and when it happens again, and I have to go lose my car for another day, I'll be sure to express my displeasure to the service manager for such poor service. Thanks again for your help.

 

[bslenter]

Unfortunately it doesn't look good. All they did was do a "hard reset", and called to let me know the issue is cleared (after having my car for four hours). Which is essentially what you did before it came back. This is after I even directed them to this thread. So if and when it happens again, and I have to go lose my car for another day, I'll be sure to express my displeasure to the service manager for such poor service. Thanks again for your help.

That's unfortunate. Did they even check codes and diagnose the multiplex unit first? Or just reset it and forget it?

 

[ZURV4N]

That's unfortunate. Did they even check codes and diagnose the multiplex unit first? Or just reset it and forget it?

Sounded like the tech checked some sort of "do this first" Honda guide book, and after resetting it, had no more interest in trying to find root cause. I'll let you know if and when I have to go back to get the unit replaced, or whatever else happens.

 

[qweedqwag]

Mine did the same thing, they finally calibrates the front camera and all is well now.

 

[TexasDavid]

Always think about a bad battery or an electrical glitch from the battery. Any time multiple codes are thrown and multiple systems fail it’s often battery and not all of the systems failing simultaneously. My Pacifica battery failed at 10 months and did the exact same thing as your Accord. Numerous similar reports across many brands.

I had the same issue is a BRAND new 2017 Charger Scat pack last December. Had a battery discharge issue and the car wouldn't start and threw a Christmas tree of blinking LEDs at us. Car had 680 miles on the odometer... Figured out some cars have poor battery grounds that lead to battery failure from the factory....