2017 Honda Accord hybrid critical problem with video.

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Jul 19, 2021
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This is a 2017 Honda Accord hybrid EX-L 2.0 with 107,000 miles. The car has been flawless up till now. Today I went to crank it and it wouldn't even start. It would only go to accessory mode and I couldn't even shift it out of park. There were warnings all over the dash for different critical failures as you can see in the video above. I disconnected the battery for 30 minutes and I was able to start the car. I took it on a short drive and the first thing I noticed was after about a tenth of a mile the cruise control light turned green and the cruise control worked again. The brake light quit flashing and then one by one all the other lights turned off. The car is working properly at the moment but I know it could happen again. This could leave my wife where she can't get it started. Can you tell me what you think the problem is?
Thanks
 
Joined
Feb 15, 2003
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Electronics can be glitchy. The other day, we had an 8AM departure in our G600 corporate jet. I fired up the plane at 7AM and was greeted with what seemed like 300 "blue" messages (non critical) and a handful of unusual amber messages. The brakes, landing gear, main entrance door, and other critical systems were all offline! Thank goodness it has great onboard diagnostics, I was able to look at each system, and see what was wrong. In each case, the CMC (maintenance computer) said "message logic, no LRU at fault" (LRU meaning component).

I have no idea what caused so many faults, but there was clearly one common theme, one key component (a DCN 'data concentration network') did not boot up correctly. By 8AM, I had shut down the plane, let it sit for 10 minutes, fired it back up, and all was well.

The suggestion above about low voltage is a very good one. It is likely that in my case, there was a low voltage condition upon APU start and the system simply did not boot up correctly.

Complex cars really are no different. I know we all expect the electronic systems to manage voltage properly. But everything from battery charge voltage to working system voltages are known to be a bit wonky on Accord Hybrids. Low bat V and especially a weak low capacity battery is very well known to cause a large number of strange issues. Including not being able to turn the car off or release the parking brake. I'd hate to be wrong, and send you down the wrong path, but as a first troubleshooting step, I'd simply purchase a new, high quality 12V battery, and charge it before installation.

EDIT: I also wanted to add that the Accord Hybrids (and other modern Honda's) don't seem to get good 12V battery life. This is probably due to the way Honda manages the charging, often letting the battery float at what we would consider lower than normal voltages.
 
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Fwiw, the CRV forums are full of similar stories and the underlying cause seems to be a bad battery. As your (non-hybrid) battery is at about the 5-year mark it may be time for a replacement. Cheaper than dealer diagnostics and about due maintenance in any event
 

hrv

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Fwiw, the CRV forums are full of similar stories and the underlying cause seems to be a bad battery. As your (non-hybrid) battery is at about the 5-year mark it may be time for a replacement. Cheaper than dealer diagnostics and about due maintenance in any event
same on the HRV..
 
Joined
Sep 23, 2006
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757 Virginia, USA
Yup the 51R is not a great one...Just about all Hondas with the 4 have them...
See if you have room to upgrade to a larger size battery. There are many YouTube videos on slightly modifying the 4 cyl. Hondas to accept a Group 24F or 35 battery in place of the anemic 51R. I did the conversion in 15 minutes on the wife's K24 Element.
 
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JHZR2

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My 2015 HAH is hard on batteries. It bleeds down the battery pretty fast. Like it will draw down to less than 12V if just sitting locked. Not that it much matters typically… the inverter powers any actuaL hotel loads, and so the most it really needs to do is unlock the doors and provide power for the computer to turn on. Not a big draw compared to a regular car.

I suspect it got so weak that it can’t boot some computers. Disconnecting it let the voltage rise just enough to help it to accept a bit more load.

You need to check the 12v battery voltage. I suspect it is low/weak. The batteries for these are tiny.
 

JHZR2

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See if you have room to upgrade to a larger size battery. There are many YouTube videos on slightly modifying the 4 cyl. Hondas to accept a Group 24F or 35 battery in place of the anemic 51R. I did the conversion in 15 minutes on the wife's K24 Element.
Not in the HAH, not in my 2015 at least.
 
Joined
Feb 15, 2016
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GA
AdvanceAutoParts sells 51R AGM batteries already; however, at steep price about $270 id say in my Area
This past weekend I bought EFB 51R for my Accord at $200
On the other hand at our CRV I have 35 AGM battery, it could fit just without OEM battery sleeve


CRV
IMG_5128.jpeg


Accord
IMG_5131.jpeg


Im hopefully for them both :D
 
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Sep 24, 2020
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New Bedford, MA
In my 2017 Accord Sport I upgraded my 51r to a 24f. I just had to go to the dealer and buy the v6 battery bracket.

I went with everstart maxx from Walmart. I have always had good success with everstart. Cheap and get the job done for me. I put everstart in wife’s 2015 Altima and her daughters 2015 jeep Cherokee.
I replace every 5-6 years, I would rather do it in my terms, ie. In my driveway and can use another car to take to store, get new one etc.. instead of being stranded in a parking lot or wherever and have to call her to bring my tools and go through all that nonsense
 
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See if you have room to upgrade to a larger size battery. There are many YouTube videos on slightly modifying the 4 cyl. Hondas to accept a Group 24F or 35 battery in place of the anemic 51R. I did the conversion in 15 minutes on the wife's K24 Element.
There is no reason to do that on the hybrids. The 12V battery does not serve the same purpose.
 
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