Oh, you are right...still half asleep. To your third question...I pulled the light bulb off before taking the readings!

Will proceed with 10+ hour readings.

Thanks again.

 

I thought so. Even with a light load, it can show a significant tap disparity that bounces back very quickly, that's why I try to capture voltages there under load.

 

I think I am making progress here.

Latest readings attached after 10 plus hours. Seems pretty stable.

Still have same P1580 code so went back through the trouble shooting. When I arrive at "update the MCM or substitute a known good unit" I am stuck with swapping to a "not so known good" unit. However, when I swap in my other MCM the code changes to 71 (flash) or P1637. This indicates an "MCM internal circuit malfunction" which of course has a remedy of "update or substitute a known good unit" trouble shooting method.
But, when I start the car in this mode, it now uses the IMA battery, first time I have heard that in a while. Otherwise running the same, IMA and engine light on and 12V light on at idle.
I think the battery is back in the land of the living. Now I have to decide if I carry the car to Honda for a update or seek another MCM. Hard to believe I have 2 bad MCM's but that is what is seems like.

 

Nope... the battery is officially back in the sh1tshow category. 0.76V is a catastrophe. Your sticks seem cooked and are suffering from extremely high self-discharge.

As for the rest, I can't say. I would be inclined to pursue "known good" before I did anything else... Salvage yard, etc.

Battery is 100% bad.

 

Maybe the better way to put it is that I think I need to chase my other problem before I come back to address the battery. My hope is that I have worked the battery back to a place where it is not the cause of the code. I realize that is not out of the realm of possibility.
Will report back as I make the next changes.

 

It's been unlikely that the battery is the cause of that code unless it's the current sensor on the junction board. I'm shocked that you're not getting other battery related codes.

We are in agreement... That's why I said "known good". You need to swap out MCM with one you know works.

http://www.insightcentral.net/forums...de-1580-a.html

If you paid for that battery, and it has any warranty or there was any claim of "it works," you need to get your money back.

 

The upside on the battery is that early in the saga when the replacement did not fix the issue I packed it up and received the refund for it. I reinstalled the battery the car came with, likely the original.

To summarize where I stand now. Original battery reconditioned to a point where it is not throwing codes. The original MCM throws a P1580. I can swap out the MCM to another and get P1637. I suspect original MCM is bad and swapped MCM is either bad or needs to have the software updated to play nicely with the installed battery (perhaps due to the presence of the heat sensor strips?) Contemplating a trip to Honda to have the replacement MCM updated, but have been less than impressed with their trouble shooting skills so far. May consider nabbing another MCM off e-bay or from Bumblebee, but may end up in the same place. Also have read where HCH 1 batteries replaced by Honda have had the heat strips disconnected to work with updated software...that would require pulling the battery, but it might be worth a try.

I do think I am closing in on this thing though.

 

Crap... mid-40s is a b1tch... I can't remember details anymore... I need to keep my own "knowledge base"...


http://ecomodder.com/forum/showthrea...tml#post515448


Pull the battery, pull the junction board, cut the red wire on the orange plate.


http://www.insightcentral.net/forums...or-strips.html


That will likely let it work with the replacement MCM, and you will then be treated nearly immediately to P1600 and P1449 - indicating bad battery.


An older battery with PTC strips NEEDS to have an old MCM. The only way it will work with a patched MCM is if you cut the wire.

 

I have just a few years on you, I know what you mean. Not to mention the issues are fairly complex and rarely does it seem like any two issues are exactly same.

I would be happy to see some different codes at this point! And it keeps me away from the dealership...

Will report back.

Thank you.

 

And those posts make for some good reading! Certainly come close to my experience so far.