Aux Battery Not Ready

JWasko

JWasko

Caught the Bug
I just saw kevman65 had to replace both batteries and wondering if I don't have a partial same situation. Typically I just turn off the ESS before I get out of the garage. I could use a Tazer or something like that to disable it, but hitting the button isn't all that burdensome for me anyways. I had forgotten to turn it off the other day, but noticed it never kicked on when I was driving. This coincided with noticing my voltage on the dash menu was running in the high 13's or right at 14 whether under load or not. Seemed high, like the alternator was working harder to push juice to the batteries. Flipped to the screen that gives info on the ESS and it indicated not ready, no interior light issue, no warning light on the dash like it was charging, no indicator that anything was amiss. Since I don't drive all that often, I did throw a trickle charger on the main AGM just to see if I topped off the juice that would clear any issue since that should charge both batteries, correct? Took it for a spin for about 20-25 minutes one way, still running the same not ready message on the ESS. Still running the same numbers on the battery voltage per in dash readings. Do I pull the aux to test? If I go to the work of pulling it, should I just chuck a new one in there and be done with it? Or just chalk it up to SNAFU and continue to hit the button turning it off and carry on? 21 JLU 2.0 without e-torque.
 
JWasko said:
I just saw kevman65 had to replace both batteries and wondering if I don't have a partial same situation. Typically I just turn off the ESS before I get out of the garage. I could use a Tazer or something like that to disable it, but hitting the button isn't all that burdensome for me anyways. I had forgotten to turn it off the other day, but noticed it never kicked on when I was driving. This coincided with noticing my voltage on the dash menu was running in the high 13's or right at 14 whether under load or not. Seemed high, like the alternator was working harder to push juice to the batteries. Flipped to the screen that gives info on the ESS and it indicated not ready, no interior light issue, no warning light on the dash like it was charging, no indicator that anything was amiss. Since I don't drive all that often, I did throw a trickle charger on the main AGM just to see if I topped off the juice that would clear any issue since that should charge both batteries, correct? Took it for a spin for about 20-25 minutes one way, still running the same not ready message on the ESS. Still running the same numbers on the battery voltage per in dash readings. Do I pull the aux to test? If I go to the work of pulling it, should I just chuck a new one in there and be done with it? Or just chalk it up to SNAFU and continue to hit the button turning it off and carry on? 21 JLU 2.0 without e-torque.
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There are usually multiple parameters that need to be met for the auto stop to work. Obviously the main battery is the main one but other could be at play as well. I would test your battery. It charging at 14v is normal like Wjco said but it could still be on its way out
 
Appreciate the feedback, without any issues with interior lights, headlights dimming, warning messages, etc., I'm not losing any sleep that the ESS isn't kicking on. Like I mentioned I usually kick it off anyways, just kicking the tires to make sure there wasn't a potential issue that I needed to address before it caused a bigger one. I'm likely a year or two out perhaps from needing to change the main, and I'll just go ahead and swap out the aux at the same time.
 
After you put your battery on a trickle charge, did you clear your DTCs? If not, try that and see if you're still getting the error.
 
wayoflife said:
After you put your battery on a trickle charge, did you clear your DTCs? If not, try that and see if you're still getting the error.
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I didn't think about that, but will clear them this morning and see what happens. Thanks for the suggestion.
 
my 2020 JT gives the same message 2 days after I bought it a few months ago.
i keep an emergency jumper pack just in case
 
Factory batteries seem to last about 3 years and then need to be replaced. Happened on my JL & JT. ESS Not Ready (ever) is like the first symptom. I let the truck go for so long that I kept getting random codes every now and then and finally the lights on the trans shifter didnt come on which Eddy mentioned in one of his videos. I had the main battery tested and it was kinda shot. Replaced and no more gremlins.
 
We disconnected the aux btty after similar issues, as well as random dash lights, and after the main battery was brought down by the dying aux battery. All happened within a couple weeks.

A fresh main battery and 2 years on, all symptoms have vanished. Everything still works. IMO the aux battery is an completely unnecessary complication -- which insures lots of people will go in for service.

Plenty of Utoob videos on how-to.

2020 Unlimited Sport.
 
JLTD said:
We disconnected the aux btty after similar issues, as well as random dash lights, and after the main battery was brought down by the dying aux battery. All happened within a couple weeks.

A fresh main battery and 2 years on, all symptoms have vanished. Everything still works. IMO the aux battery is an completely unnecessary complication -- which insures lots of people will go in for service.

Plenty of Utoob videos on how-to.

2020 Unlimited Sport.
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Do you run an oil catch can, aftermarket skid plates, and Milestar tires by any chance?
 
JLTD said:
We disconnected the aux btty after similar issues, as well as random dash lights, and after the main battery was brought down by the dying aux battery. All happened within a couple weeks.

A fresh main battery and 2 years on, all symptoms have vanished. Everything still works. IMO the aux battery is an completely unnecessary complication -- which insures lots of people will go in for service.

Plenty of Utoob videos on how-to.

2020 Unlimited Sport.
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New Member
 
Dang y'all are harsh.

Pardon me for being brand new to the site and not seeing the previous commentary on this situation.

I've been working on vehicles since the 70s, did a good bit of research (much more than 1 video btw) and am very happy with the real world results.

I'd appreciate it if you'd take a moment to educate me on what I missed - rather than simply calling me a tool - or at least make an intelligent noninsulting relevant comment.
 
JLTD said:
Dang y'all are harsh.

Pardon me for being brand new to the site and not seeing the previous commentary on this situation.

I've been working on vehicles since the 70s, did a good bit of research (much more than 1 video btw) and am very happy with the real world results.

I'd appreciate it if you'd take a moment to educate me on what I missed - rather than simply calling me a tool - or at least make an intelligent noninsulting relevant comment.
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What fun is there in that?

Long story short, legend states that the aux battery protects the computer in these turds.
 
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