ESS not ready

[629]

I searched threads for a while and decided to post. I purchased a new to me 23 gladiator from a jeep dealer with less than 2000 miles. From the jump the ESS has not worked says not ready. When I asked the dealer when buying they simply said “some don’t work”. The jeep was near perfect exactly what I wanted and I hate ESS so…

There’s nothing plugged in under the dash (tazer) etc and none of the known (to me) defeats are done. ESS button lights when pushed. There is a curt trailer brake controller wired up. I unplugged it and no change (I did not unwire it just unplugged from connector). Battery at least main battery was checked and is fine. The only other electrical modification visible is a winch. The prior original owner obviously marked the owners manual in the ESS section. He was in his 70s, so I’m guessing he did something to defeat it. Or maybe it didn’t work and that’s why he marked the pages. Everything else works fine.

I don’t want it to work. I was looking at tazers and auto stop eliminators while doing the paperwork at the dealer lol. However it would be nice to know why it doesn’t work.

For background I work on my own vehicles and have owned 15 plus jeeps…so I’m fairly good at trouble shooting.

So after all that…the question is could I be missing something?

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[Mr._Bill]

It can be from mis-fires, or other issues, but the ESS not ready message is usually from a low voltage condition. It may not be low enough to prevent the vehicle from starting or running, but it is low enough that the monitoring system is showing the not ready message. The first step would be to separately charge each battery with a good AGM charger and reset the IBS. Let them sit for a while with no load, and then check the voltage. A healthy battery will read about 12.8 volts.

 

[Wildtoad]

There is a list of conditions that must be met before the ESS will function. Have you eliminated any of them as being the culprit?

 

[629]

It can be from mis-fires, or other issues, but the ESS not ready message is usually from a low voltage condition. It may not be low enough to prevent the vehicle from starting or running, but it is low enough that the monitoring system is showing the not ready message. The first step would be to separately charge each battery with a good AGM charger and reset the IBS. Let them sit for a while with no load, and then check the voltage. A healthy battery will read about 12.8 volts.

I was afraid that might be the issue. So I did check voltage on the main battery and it’s fine. I will charge both this weekend and disconnect power to reset IBS.

 

[629]

There is a list of conditions that must be met before the ESS will function. Have you eliminated any of them as being the culprit?

I believe so. It’s only saying “not ready”. When the seat belt is not on (for example) it reads not ready seat belt..etc etc.

I’m wondering if the original owner did something I can’t see.

The brake controller seems odd to me as you could clearly tell no hitch had been in the receiver.

Also it’s got a lot of little accessories non electrical but clearly the guy opened a jeep catalog. So I just wonder what he did in the short 1500 miles he drove it.

Like I said I don’t want it to work but I’m curious as to why.

 

[mdyucca]

Unfortunately we have Jeeps with ESS and two batteries. The batteries and ESS are the most discussed issues on this forum. Just type in ESS in the search box and you will find information for days on ESS. In my opinion ESS and two batteries are the most annoying features of JT and JL models. Have fun with you new Jeep.

 

[RJ McAuliffe]

I searched threads for a while and decided to post. I purchased a new to me 23 gladiator from a jeep dealer with less than 2000 miles. From the jump the ESS has not worked says not ready. When I asked the dealer when buying they simply said “some don’t work”. The jeep was near perfect exactly what I wanted and I hate ESS so…

There’s nothing plugged in under the dash (tazer) etc and none of the known (to me) defeats are done. ESS button lights when pushed. There is a curt trailer brake controller wired up. I unplugged it and no change (I did not unwire it just unplugged from connector). Battery at least main battery was checked and is fine. The only other electrical modification visible is a winch. The prior original owner obviously marked the owners manual in the ESS section. He was in his 70s, so I’m guessing he did something to defeat it. Or maybe it didn’t work and that’s why he marked the pages. Everything else works fine.

I don’t want it to work. I was looking at tazers and auto stop eliminators while doing the paperwork at the dealer lol. However it would be nice to know why it doesn’t work.

For background I work on my own vehicles and have owned 15 plus jeeps…so I’m fairly good at trouble shooting.

So after all that…the question is could I be missing something?

I had similar issues with my New-to-me '21 at about 25,000 miles. My normal commute often involves not needing to come to a complete stop, so I cannot tell when the ESS is not working unless I go to that screen display. The dealership replaced the IBS sensor, and I have had no issues with it since. I am usually surprised when the ESS works.

 

[629]

So I just looked up removing the aux battery (to potentially charge it separately). All I can say is WOW, what a dumb location. I’m going to charge them together first just to see what happens.

While I’m perfectly capable of pulling the entire drivetrain…I don’t want to tear apart my new jeep. This might turn out to be a well enough alone situation.

Besides the 99 XJ is always ready to go.

 

[Mr._Bill]

So I just looked up removing the aux battery (to potentially charge it separately). All I can say is WOW, what a dumb location. I’m going to charge them together first just to see what happens.

While I’m perfectly capable of pulling the entire drivetrain…I don’t want to tear apart my new jeep. This might turn out to be a well enough alone situation.

Besides the 99 XJ is always ready to go.

All you need to do is disconnect the Aux Battery Negative cable from the Negative Post of the Main Battery to separate them for charging.

 

[629]

All you need to do is disconnect the Aux Battery Negative cable from the Negative Post of the Main Battery to separate them for charging.

Will do. Thanks.

 

[TestMule]

All you need to do is disconnect the Aux Battery Negative cable from the Negative Post of the Main Battery to separate them for charging.

There are plenty of threads here showing how this is done. There was a change about mid-year 2021 on the cable wiring at the battery so depending on what year you have you'll want to follow the directions shown in those threads.

The aux battery in my 2021 Gladiator gave it up and killed the main battery as well. I disconnected the aux battery, pulled the aux battery lead to the main battery back and insulated the terminal end, pulled a fuse (no. F42 I think), and made sure my ESS dash switch was set to turn off the ESS.

I was fortunate to have a local friend who had a main battery sitting in his shop that he didn't need after he did a dual battery upgrade to his JT so he brought it over and the truck fired right up with no CEL, no ESS messages, etc...

 

[ATL_Rubi]

Mine is also doing this. 2023 with 37k miles, just shows “not ready” I’ve sat the batteries on a tender over night and I get one stop start out of it before it says not ready again. Guess it’s time to pull the batteries and replace them.

 

[Lost1wing]

Mine is also doing this. 2023 with 37k miles, just shows “not ready” I’ve sat the batteries on a tender over night and I get one stop start out of it before it says not ready again. Guess it’s time to pull the batteries and replace them.

Not necessarily. Have you tried to charge both batteries independently and resetting the IBS? Try just reseting the IBS for now and see if it gets any better. If i does, isolate the 2 batteries and do the IBS reset again.

 

[Great Offender]

When I bought my "new to me" 21 I noticed it never worked but didn't even know it was a feature until I started reading posts about it.
Dealer took it under warranty and replaced the IBS. I drove about a mile before I turned around and brought it back. Still didn't work. Aux battery was replaced and it worked 1 time on the ride home, surprised me, turned it off, and it never worked again.

 

[jjdustr340]

I know it seems very basic, but did you make sure it wasn’t one of these:

Sometimes it’s the most simple of things.

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