Stop/Start Not Ready-Battery Charging

[rafaelsmith]

For past few weeks I notice my Auto Stop/Start has not been working. Didn't really think about it cause I hate it....but decided to look on the instrument cluster and it shows: "
Stop/Start Not Ready-Battery Charging
"
I would think about 1h of driving it would have charged but message persists.

Bad battery? Bad batteries?

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[Clay]

One, or both batteries are going to be bad! Both of mine had to be replaced under warranty, so go ahead and take it to the dealership. The dealership tech told me that the ESS was the culprit, so I have disabled mine. There are other threads on this issue.

 

[jebiruph]

That message is based on the battery sensors analysis of the main battery. There could be a problem with the main battery, a problem with the battery sensor, a problem with the aux battery draining the main battery or no problem at all.

Before you buy anything, you can try using a battery charger to top off the batteries to see if that fixes it, and sometimes reseting the battery sensor by unplugging it helps. It's probably best to get it to the dealer and get the batteries individually load tested.

 

[johnparjr]

I took mine in this week they reset the battery sensor and all was good for about a day and then it went back to ESS not ready battery charging. So brought it back in and then they replaced the ESS battery and all has been good now for a day and we will see how this goes

 

[ArmyMP]

My JTRD has been to the shop 3x for Stop/Start. First time it got new batteries; second time a new small battery and a PCM flash. Now it's in the shop till 1/7 for a new PCM.

 

[JAVYPRO]

Hey guys,
My JT Rubicon was at the dealership for the same reason, the dealership did a reset and the latest software update as per the latest recall but the same day while driving home from the dealership I got the ESS message.
Going back on 12/31/2021
Javy

 

[Mustangr]

Most likely a least 1 battery. I have had mine replaced for the same issue.

 

[Adawg1203]

For past few weeks I notice my Auto Stop/Start has not been working. Didn't really think about it cause I hate it....but decided to look on the instrument cluster and it shows: "
Stop/Start Not Ready-Battery Charging
"
I would think about 1h of driving it would have charged but message persists.

Bad battery? Bad batteries?

I don't think that is indicative of there being an issue with the system. If you are running the heat/cooling system this tends to happen especially in winter.

It does take a while for the system to charge back up (based on conditions) but unless you are seeing a code or fault indicator the aux battery is charging.

I don't drive my gladiator much so this happens routinely but the system charges itself and things are good to go.

The vehicle should tell you if there is an issue with the charging system so I wouldn't worry too much about the stop/start not ready as that is normal.

I'd be more concerned if the battery was NOT charging. Again, in my experience It does take the system awhile depending on circumstances to charge. There are conditions that effect start stop and the manual may list out some of those scenarios.

 

[Jeep-A-Kneez]

Yeah, mine is out as well. Briefly the check engine light was on then off??? Then I noticed that start/stop quit working. To the dealership I go, was informed that the egr valve/sensor was bad, can't remember which, part has been on order since early November. Questioned about batteries, was told they checked good. Don't miss the start/stop not working, but being a new vehicle, everything should, like the air conditioning!!! Having that looked at today.

 

[rafaelsmith]

Main battery had to be replaced.

 

[jenn191919]

Just had my 2020 Grand Cherokee in for the Third time in regards to this issue. First time said everything was functioning normally. reset and sent me on my way. two weeks later i was back and they replaced the Aux battery worked on the drive home. three days later and hasnt worked since. time to make another return visit. This dealer is not a fan. Also less than 10,000 miles. Had to force them to switch the battery. Its a huge hassle to have to make an appt and keep dropping this thing off.

 

[DidYouJustGrabMyAss]

Main battery had to be replaced.

yeah, seems to be an issue. My 21 Mojave needed both replaced off the lot on day 1. Both were crap.

 

[freebird_78]

I had this issue recently.

First, this only has happened since it's gotten below freezing here. I'm sure that's not a coincidence.

Second, had some interesting findings, and what is, for my situation, a fix (at least for the last few days).

Background: I have a JTRD, and it exhibited similarly to the OP. I've also had a bad ground issue on literally day one, but that was resolved and hasn't occurred since the dealership fixed this. It exhibited similar symptoms, but also a lot of codes, running issues, etc.

First troubleshooting step was to see if the ground fix that the dealer did had begun to let go. Monitored battery voltage while gently "wiggling" the ground points they repaired. No fluctuation.

Second troubleshooting step was to pull both batteries and test them. I have a pretty decent battery tester, and a variety of battery chargers (LiOn, AGM, flooded, etc etc). The main battery (rated for 700CCA) tested out perfectly (load tested, charge voltage, internal resistance). At this point, I was suspecting the infamous AUX battery. Tested it to the rated 200CCA, and it failed miserably with an internal resistance of 22.8mOhm (a good AGM should be low single digits). I threw it on a conditioner specifically for AGM batteries. Usually, conditioning takes several hours. 2 minutes later, I get the message "conditioning complete". RED FLAG. Re-tested, and got vastly different results. Showed good, with a good internal resistance (3.xx mOhm). The results were extremely sketchy. I suspect I had bad contact on the first test. Put both batteries back in the truck. First drive out, everything looked back to nominal. The "smart" charging system was cycling depending on load, like it's supposed to, as opposed to a static 14.0VDC like before. I thought it was "fixed". Start/Stop showed ready. But that only lasted about 30 minutes. Soon, it went back to the symptoms reported in the OP. I thought maybe the initial test of the AUX was correct afterall, and it was bad.

Dreading a trip to the dealer, I decided to try one last thing. I'd read about the IBS reset procedure, so I decided to throw a hail mary and try it. Left everything the way it remained after the second troubleshooting. Disconnected IBS sensor for about 5 minutes, and plugged it back in. Drove to work and it was clearly re-calibrating/re-learning. Would hold 13.0V for a minute or two, then 13.1V for a minute or two, all the way to 14.0V. HOWEVER, on decel, it would still climb to 14.5-6V like it nominally does, then back to wherever it left off "re-learning" under load. Interesting results. After a couple of drive cycles, it seems to have gone back to completely nominal operation. It varies from 12.4 to 14.5, again depending on load, just like it's supposed to. Shows Start/Stop Ready after a couple of miles. It's been a week now. Still have mornings below freezing, so that variable is still there, but the charging system is behaving nominally, as far as I can see.

 

[rgboehm]

My JTRD has been to the shop 3x for Stop/Start. First time it got new batteries; second time a new small battery and a PCM flash. Now it's in the shop till 1/7 for a new PCM.

Mine stopped working. so put a charger/tester on both batteries. Easy way to isolate batteries, is to disconnect negative terminal -- easiest way the small nut on the voltage sensor. Connect charger to positive terminal and then for the small battery connect negative to negative cable just disconnected. Then after that is fully charged, connect negative charger connector to big battery terminal. Small battery charged fully in an hour. Big battery never completed a full charge. So it is probably on its way out. But now Stop/Start is working??? One thing I noticed if battery voltage when running shows 14.3V then Stop/Start doesn't work. Now showing 14.1V (shown on instrument panel).

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