It seems the faulty sensor was not the issue as I am having dead battery issues again.
Went to start car. Completely dead. No lights, sound, clicks, nothing.
Jump the battery, it starts up immediately no hesitation. Go for a good long ride and have no problems for about a week. Battery dies again, push the start button absolutely nothing. I’m sitting in the car fiddling with the fob because I’m trying to open it, thinking I’ll try to change the battery, to see if that makes any difference the dashboard suddenly comes on and the car starts.
So I think maybe there is a short/problem with the fob. I get a new one and it seems to work fine for a couple weeks but now it has died again.
So from reading all these posts there seems to be some mysterious problem effecting all these Fits and no one is able to come up with any definitive solutions.

 

[QUOTE=wasserball;1457954]It has to be a circuit/component that wears down, as I never had any issues the first 50,000 miles. And now I can measure it daily as it goes down.

 

Same issue, I am working on it, but the dealers are no help.

 

Your Fit is possessed.

🤣🤣🤣🤣🤣🤣

 

Bought a used 2015 FIT EX for my daughter. For a week everything seemed fine. Then the battery started dying overnight. My mechanic replaced the Alternator. Didn't fix it. Went down the Rabbit Hole of Parasitic Drain and watched numerous videos and forums (for Hondas, Toyotas, BMW's etc.) and checked it. It was drawing around 800 milliamps when all shut down. Looked like fuses 21 and 29 (BACKUP and BACKUP MAIN). My mechanic looked at disconnecting the Radio and the Console based on wiring diagram. It reduced the drain by SOME but not all the way and was still unacceptably high.. I suspect the door locks/keyless entry system as the Driver Side Master Door lock switch is jammed. (But it all works just fine with the FOB....I posted on this earlier). I ordered a replacement but it isn't here yet. My mechanic said he would try disconnecting that switch and see if it improved things. Wondering if anyone has had and solved similar issues. I also tried removing the AC Clutch Relay (something I found in my searches) but that didn't seem to help. Would really like to figure it out vs. replacing lots of things and still not fixing it.

EDIT: UPDATE in case it helps anyone else. Problem was the Immobilizer system not going to sleep. Software update fixed it. No more parasitic drain! Hoping there isn't something else going on that is causing the Immobilizer software to glitch. Just got it back, but it started 2 days in a row after sitting overnight, so hoping it is FIXED. Also replaced the door lock switch with a cheap used part from Ebay. Not the problem, but now I have a working master door lock switch!!

 

Finally bought a portable charger to keep in the car. Seems to start reliably with a jump so I’m not putting anymore money into trying to find an answer to this mysterious problem that seemingly has no rhyme or reason whatsoever. So aggravating because I love the car.

 

This is only a temporary solution.

Using a portal auto battery charger as a way to start your car on an ongoing basis is not a viable long term solution.

Go to a competent Honda Dealer to fix this issue.

 

I only need to use it once every month or two and it seems like several people have this identical problem and have spent a lot of money at dealerships trying to resolve the issue to no avail.

 

If you're not far from the Chicago area,

Go to Napleton Honda in Morton Grove Illinois just outside of Chicago.

Outstanding Honda maintenance and repair dealer.

 

That may be the culprit, as its what I suspected as both the 2015 and 2016 didnt do this at first, but started around the same time as we take them to the dealer for all service pretty much together.

 

Tell me about it, I have extra batteries in the trunk and trickle as well as regular chargers for both cars trying to keep them going...

 

Tell me about it, and its $200 plus each time to check for parasitic drain...........

 

Good luck!! Just reporting back that since the Immobilizer software update, NO MORE DRAIN. Car starts fine every morning, even now that WINTER has arrived in New Jersey!!

 

No, mine went down to 12.1 volts just over the weekend while I was away, so nothing I did.

 

No way, now will have see if the dealers can give me a appointment before next year. And I mean that....!

 

EDIT: UPDATE in case it helps anyone else. Problem was the Immobilizer system not going to sleep. Software update fixed it. No more parasitic drain! Hoping there isn't something else going on that is causing the Immobilizer software to glitch. Just got it back, but it started 2 days in a row after sitting overnight, so hoping it is FIXED. Also replaced the door lock switch with a cheap used part from Ebay. Not the problem, but now I have a working master door lock switch!![/QUOTE]
Hi, can you PLEASE tell me how to update the IMMOBILIZER system's software?
thank you!!!

 

The tech at the repair shop did it. I don't really know how he did it but I am assuming he had some diagnostic/update device like the Honda i-HDS:

https://store.honda.com/hondaacura-i-hds-and-vsp
https://honda.oemdtc.com/342/i-hds-d...mming-software

Note, that it may not necessarily be this in your case. In my long journey to get this fixed, it was apparent that there are a TON of modules that can potentially cause this by staying alive and keeping the computer active and drawing current.

Diagnosis is the tough part, but I guess he had the right tool/software to pinpoint it.

 

I recently took my 2018 Fit in for a software update to fix rear camera problems (an official recall from Honda) and when I was picking my car up I asked if they did a system wide software update as part of the process. The service person said, not as such, but they do check for other modules which have older software and do update them as part of their process. This was my second trip in for this camera software update, the software fix a year earlier apparently didn't work so we had a do over with a new recall.

 

When I had a GD1, I was having the dead battery issue, had the alternator tested at the auto parts stores, always tested good.
Fianlly took teh alternator to a shop that does custom rebuilding of alternators and he hooked it to his tester and the ALT was never getting over 13V.
He replaced teh rectifier and 14.7 , he said the diodes in some japanese corp based cars can partially fail and then dont pass correct voltage form all three phases in teh alternator..

He must have been right it lasted for 4 years till it got totaled. And the new rectifier was < 30 bucks.

 

Lucky for the quick diagnostic! For me, when I was trouble shooting it, my first thought was the alternator as well. Using my own multi-meter it looked like it was putting out 14.5 volts or so and I also took it to the Auto parts store and Alternator and Battery tested OK. When I took it to my mechanic, he said the Alternator was bad (not charging) and the belt was also old and should be replaced. I didn't really think that was the case since when it RAN the battery stayed charged for me, but I figured, maybe it was on its last legs, or maybe, as you said there was a bad diode/rectifier with intermittent failures. ~$500 later, the car wouldn't start the next morning and I was back to square one with Parasitic draw diagnostics until the strange Immobilizer issue came to light.