When I scroll through the menus, it says the auto stop/start battery isnt available and "charging", which I dont care about since I dont like it anyway, but is it something to worry about taking to a dealer to fix? It's under warranty, but if its not going to cause damage to the main one, I'd rather not wait a day for them to replace it.
Posted Sep 25, 2023, 2:25 PM UTC
Yep, the aux battery is a pain in the but, once it goes out it starts electrical gremlins like auto start stop breaking, the aux switches if you have them no longer function, it can leach from the main battery and give you trouble on cold mornings. And why they decided to place it under the fuse box will have me confused til the day I die.
Yea I've read how you have to take the fender off, or the fuse box, just to change the regular battery.
The main battery is 1 screw attached to a rubber foot, the aux is under the Fusebox and requires what feels like 15 Bolts to access.
I disabled my aux battery (guides all over web). I don't use the feature anyway. So figured why take the risk of it killing my main battery when it goes bad.
Is that the only thing it powers, or do other things rely on it? Wifes volvo had an issue, but it messed with the fob, wouldnt unlock 1/2 the time or even just start.
From what I've read online the aux battery is only for the ESS service. I have not noticed any other issues yet. No error codes. Etc
Super easy to re-attach if something does go haywire. But essentially everything seems to run off the main battery now. Even ESS if I use it. But I always turn it off at start up anyway out of habit.
They won’t replace under warranty unless the battery test bad. My start/stop not ready was on for months and the battery tested fine so they wouldn’t replace. Another few months went by with start/stop still not working and then the electrical gremlins started. Took it in, had to convince them to test aux battery instead of chasing the random codes it started throwing (water in fuel, diesel preheat in process, etc random shit). The Battery tested at 0V so they finally replaced.
Moral of the story is your aux battery is most likely failing but they won’t replace under warranty until it pretty much leaves you stranded.
Would it be better just to disconnect it and not worry about it? Or does it power other things?
I would assume it would test bad, since its been saying it for 3+ weeks
Maybe, maybe not. Had them check it three separate times after start/stop was not working for weeks. Always tested good until it started throwing codes on startup.
It's not always the aux battery causing the issue, my main battery died and my aux is still going strong and it's over 4 years old.
When I check it through the menus its usually at 14 volts or so while I'm driving
You can’t just disconnect it, there are a few more steps, see here for instructions.
That looks like a pain in the ass
Not too bad. Basically just remove the aux ground line from main battery terminal. Pop out fuse 42. That is it
I just had both batteries replaced on my gladiator under warranty. Now same thing happened to my wrangler. The aux battery dies and then starts to drain the main until both are ultimately dead. Can confirmed it’s warranty covered.
I feel like there are going to be a lot more dead aux battery posts on here since many are going out of warranty on the earlier models. My 2020 just had it happen a month out of warranty. I did the delete and replaced my main battery.
Had same issue in my wrangler. Both batteries had to be replaced. Luckily, under warranty. After the batteries were replaced I haven't had the problem.
I was just like you though. I don't want the start/stop so it didn't bother me but, it was under warranty and it saves me from having to replace them in an 'emergency' that might leave me stranded somewhere.
I had “Stop/Start Not Ready” for a while but ignored it since my doors and top was off thanks to warm weather. Put everything back on and the message was still there. Another message popped up something to the effect of auxiliary switches disabled charging battery, I forget the exact message. This new message popped up over this last month every other day and when I went in for my 25k maintenance I mentioned all of this.
Folks looked and talked like this was a common issue with the auxiliary battery and looked into it. Warranty covered replacement for that battery and the main battery since it apparently was sapped and needed replacement too. I would have it looked at personally given we’re going into colder months even if you plan to turn off stop/start when you hop in.
Yea I figured I would, only had it a few weeks and I hate that start/stop anyway, but I guess if its free, might as well