Start/stop not ready

[Fishee]

Ok sorry I know this has been beat to death but here it is. I have the message on dash that says start/stop not ready. It has been like that for months, probably since the end of summer. My main battery voltage still shows like 14.2v on offroad pages and have had no issues. Went to dealer since my 36 months is up in a couple weeks and they said it is covered as long as I didn't do any mods with light bars or anything to battery. Well I installed the OEM Mopar Aux switches myself and since it wasn't done by a dealer warranty could be voided, they couldn't give me a straight yes or no. Well they have to keep it a couple days and will give me a loaner for free BUT if they say warranty is voided I will get stuck with a bill for rental and repair.

Question is has anyone found something OTHER than the aux battery being the problem? I would rather just pay for a battery and do it myself and not get stuck with a bill. Thanks

Sponsored

 

[sharpsicle]

Ok sorry I know this has been beat to death but here it is. I have the message on dash that says start/stop not ready. It has been like that for months, probably since the end of summer. My main battery voltage still shows like 14.2v on offroad pages and have had no issues. Went to dealer since my 36 months is up in a couple weeks and they said it is covered as long as I didn't do any mods with light bars or anything to battery. Well I installed the OEM Mopar Aux switches myself and since it wasn't done by a dealer warranty could be voided, they couldn't give me a straight yes or no. Well they have to keep it a couple days and will give me a loaner for free BUT if they say warranty is voided I will get stuck with a bill for rental and repair.

Question is has anyone found something OTHER than the aux battery being the problem? I would rather just pay for a battery and do it myself and not get stuck with a bill. Thanks

Start/Stop Not Ready can mean a TON of things.

Yes, many people have found things other than the aux battery that can cause this. Like, the main battery! Parasitic draw from accessories. Blown fuses. Faulty switches or sensors. This is all assuming you don't have a condition that isn't ESS related that it's designed not to operate with, like the wheel always turned or the climate control always blasting or engine not up to temp.

ESS needs everything just right to operate. Saying it's "not ready" is not specific enough to understand anything unfortunately.

And before others jump in, 14.2v is NOT the battery voltage. That's the system's overall current voltage, which in that case is the alternator charging voltage. The only real way to check a battery's voltage is to disconnect it from the system and check it by itself.

Let the dealer check it out. They'll test the batteries and replace if necessary. Get all that done first and see what happens. No point trying to jump over them; let them do their work first. If they try to say the warranty has been voided, they're full of it.

 

[Nitroexpress]

It can definitely be something other than the auxiliary battery. I've completely isolated that battery and still have this issue. Many will probably tell you to read the extensive threads on this topic. I have done that, but still don't have a solution....

 

[aldo98229]

The batteries Jeep installs at the factory are notorious cheap. Having the dealer swap out the OE batteries with two of the same kind won't solve anything, only postpone the inevitable.

Best thing you can do is replace BOTH batteries with an aftermarket brand. It isn't difficult to do; all you need is to watch a YouTube video, a 10mm socket, and a strong back. I'd say you have a 70% chance that this will solve the problem for good.

You don't need to buy anything too expensive, either. The store brand batteries from Auto Zone or O'Reiley Auto Parts are made by the large battery manufacturers and are of very good quality.

After 18 months I had to replace both batteries on my 2018 JL. I drove to O'Reily Auto Parts, asked at the front desk, they pulled two direct replacement Super Start batteries, and swapped them myself. The aftermarket batteries were still in perfect working condition when I traded it two-and-half years later.

Good luck.

 

[Lost1wing]

In park, you will see the not ready message as well. Usually once you put the selector in drive you will see a more descriptive reason for stop start not being ready. The owners manual gives you a list of reasons.

 

[Fishee]

Ugh I know it could be a whole bunch of things but everyone seems to point to the aux battery on the threads. I would rather pay for an aux battery or both rather than potentially getting stuck with a large bill from the dealer. So is the concensus to always replay both rather than just do 1?

 

[Fishee]

And like I said it has been like this for MONTHS and I would think if the aux battery went bad it would have drained my main by now. Is that not the case? Would O'Reilly or whoever get an error code to point me in the right direction?

 

[Nitroexpress]

And like I said it has been like this for MONTHS and I would think if the aux battery went bad it would have drained my main by now. Is that not the case? Would O'Reilly or whoever get an error code to point me in the right direction?

The Aux battery going bad absolutely doesn't mean it will drain your main (although it could). I think you are to the point that reading on the topic will get you some answers to basic questions like this. I hate to be "that guy" by saying that, but there is indeed quite a lot written on this forum regarding this annoying problem. I've read about it quite a lot and still don't have a solution, but basic questions will easily be answered.

It's very easy to isolate the aux battery. You don't need to remove it.

 

[sharpsicle]

And like I said it has been like this for MONTHS and I would think if the aux battery went bad it would have drained my main by now. Is that not the case? Would O'Reilly or whoever get an error code to point me in the right direction?

There may not be an error code. "Start/Stop Not Ready" isn't an error indication by itself, just a notification. Is the MIL light or some other light on? If not, there's likely no code to pull.

If you are going to replace the batteries, I highly suggest doing both. Kind of like other things like tires or brakes, don't do just one to find a problem or a need to replace the others later on. Do them both, it's cheap insurance and a good preventive measure.

 

[Lost1wing]

Ugh I know it could be a whole bunch of things but everyone seems to point to the aux battery on the threads. I would rather pay for an aux battery or both rather than potentially getting stuck with a large bill from the dealer. So is the concensus to always replay both rather than just do 1?

If you do not have a meter to check your battery voltage, the next time you go out for a drive, do not depress the brake when you hit start. With the ignition on and engine off select the vehicle info page and read the battery voltage. It still isn't accurate because of other things running.

The only time I ever see the not ready message is when the Jeep is in park or briefly after a stop start event.

After your engine is warm enough, a battery charging message is displayed if the computer is not happy with the charge state of one of the batteries.

 

[ragsman]

After my aux battery died and I did the aux battery delete and pulled fuse 42, I got this message also right afterwards. After I recharged my main battery, I cleared the codes with my Tazer mini and it went away. I think a low system voltage had caused it to come in (after the aux battery delete) and it didn't clear on its own until i cleared the code with the tazer mini.

 

[Lost1wing]

Don't get hung up on your batteries just yet. I would do some testing before unloading a few rounds at it.

 

[Mr._Bill]

Ok sorry I know this has been beat to death but here it is. I have the message on dash that says start/stop not ready. It has been like that for months, probably since the end of summer. My main battery voltage still shows like 14.2v on offroad pages and have had no issues. Went to dealer since my 36 months is up in a couple weeks and they said it is covered as long as I didn't do any mods with light bars or anything to battery. Well I installed the OEM Mopar Aux switches myself and since it wasn't done by a dealer warranty could be voided, they couldn't give me a straight yes or no. Well they have to keep it a couple days and will give me a loaner for free BUT if they say warranty is voided I will get stuck with a bill for rental and repair.

Question is has anyone found something OTHER than the aux battery being the problem? I would rather just pay for a battery and do it myself and not get stuck with a bill. Thanks

The life expectancy of batteries in the JT is about three years. The ESS not ready message is an indication that the electrical system needs checked. The batteries are paralleled together all the time, except during ESS events and the startup test on the Aux battery. The most common reason for the ESS not ready message is low voltage from the batteries not being charged. As the batteries age, it becomes more difficult to keep them charged.

The most common fix, with your symptoms and battery age, is to replace both batteries. If you want to do the dealer dance and get OEM batteries, that is an option. Jeep has a specific process that dealers have to follow for warranty replacement of batteries. Jeep makes the decision, not the dealer, on which batteries get replaced.

My batteries lasted past the warranty period. The Main battery failed first, followed by the Aux battery about six months later.

 

[ErylFlynn]

I don't know your build date or when you bought it, but you are in that age range we hear where you start hearing of issues. If the battery is not the cause, you are not too long from it being the cause. You can if under warranty have the dealer deal with it and put batteries in that will last 2-3 years tops and kick the can down the line or replace them yourself. Either way it is about that time and better to replace them before they give out and leave you stuck.

 

[oknation]

When I first received my 2020 Jeep Gladiator Overland I would always have to push that button to make the stop/start feature stop. It was annoying beyond words! Anyway, after a short period of time (for some reason) it stopped making me have to hit the button and I would brake normally and the engine wouldn't stop. I thought "How great that is!!!" I also didn't get any Aux light on the dash either. My Gladiator operated as if I didn't have the ESS feature at all. Fast forward to January 2024 I got an error message on my dash regarding the Aux battery and it would not shut off at all. I took it into the dealer as I needed to get a newly found small "death wobble" issue figured out at only 23808 miles that just started when hitting a bump out on the interstate. The dealer told me that my warranty had expired in Nov 2022. I told him, "that figures" and thankfully the stabilizer was replaced under the extended 8-year warrant due to the numerous death wobble issues, so that was free. Regarding the batteries the shop stated on my bill the following: "AUX BATTERY SHORTED OUT AND PUT A DRAW ON MAIN BATTERY / REPLACED BOTH BATTERIES / WORKING AS DESIGNED AT THIS TIME INCLUDING DIAG AND REPROGRAMMING. My cost for battery one was $306.00 and for battery two $168.00 for a subtotal of $474.00 plus labor $374.99, shop supplies $35.00, environmental and waste disposal $20.00, so my final bill with tax $43.14 was $947.13. WOW!!! Batteries sure have gotten expensive. I remember being able to buy one battery for around $125 or so. Having the unwanted ESS feature and these two SUPER EXPENSIVE BATTERIES SUCK FOR SURE!!! Oh well, it is what it is.

Sponsored