Auto Stop / Start non-functional?

[SBLACK502]

they are covered for 3 years 36k miles. The batteries are the main culprit for a lot of electrical issues with the JL.

I'll look into that. It's a 2022 with 29k miles so still has the bumper to bumper warranty. Hopefully batteries are included in that.

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[AndySpill]

James: just in the need of ruling out things, is it correct to say that you don't see, in the dash (i.e. the EVIC) an icon near the "E" (as in fuel empty letter,) that appears as the capital letter "A", with a near circle around it, followed by an exclamation point?

This would be a sign that the vehicle has turned off the ESS system for you. A situation where this might happen in dual AGM battery JLs, like your model year's, is where upon attempting to cold crank, the standard test of the ESS battery (alone) jut prior to cold crank fails, as does the crank attempt, but the subsequent crank attempt succeeds.

In all but the earliest of 2018 dual AGM battery JLs (which won't start with a dead ESS battery barring a software upgrade) a dead ESS battery (in dual AGM battery JLs) causes the first attempt to crank to fail, where subsequent attempts to crank go only against the main battery, and if successful, engage this aforementioned dash light, where all future cold cranks happen on the first try, only against the main battery, until such time, if any, at the cold crank after the ESS battery is replaced with an energized one, or one of the battery bypass hacks common in this forum is employed.

 

[Chupacabra]

Even after replacing both batteries, my ASS system is very intermittent. If I put my NOCO on and top the batteries off, it'll work reliably for 4-6 weeks then quits working again. If I take a very long road trip, it'll work again for a bit then stop.

Basically the ASS system in these Jeeps is a horrible design requiring two batteries to be well charged or it just doesn't work. Funny how every other maker seems to be able to make ASS work fine with a single battery. I've owned BMWs, Subarus, and have friends with Fords and theirs all work fine, every time with a single battery.

You can try replacing the batteries but odds are it'll just quit working again fairly soon after you do it. If it's not bitching on the ASS screen about battery charging issues I wouldn't even bother.

 

[AndySpill]

Even after replacing both batteries, my ASS system is very intermittent. If I put my NOCO on and top the batteries off, it'll work reliably for 4-6 weeks then quits working again. If I take a very long road trip, it'll work again for a bit then stop.

Basically the ASS system in these Jeeps is a horrible design requiring two batteries to be well charged or it just doesn't work. Funny how every other maker seems to be able to make ASS work fine with a single battery. I've owned BMWs, Subarus, and have friends with Fords and theirs all work fine, every time with a single battery.

You can try replacing the batteries but odds are it'll just quit working again fairly soon after you do it. If it's not bitching on the ASS screen about battery charging issues I wouldn't even bother.

John: everything you've said I think is spot on. That isn't to say that some degree of nuance won't find me, on this rare occasion, coming to Stellantis' defense.

Stellantis needed to pass the EPA's ESS test to report better MPG stats, to meet CAFE (corporate average fuel economy) standards, to not pay enormous penalties that would have been reflected, in part, in our purchase price.

Novels have been written on how these EPA standards were poorly written and ESS systems in generally that I don't disagree with, and I'm all about doing my "green" planetary share. It was about Stellantis passing a new vehicle test, not whether ESS engages 6 months down the line.

Stellantis couldn't design their ESS system with one battery like so many other vehicle manufacturers who don't, unlike Stellantis, have to content with so many JL owners adding too many energy hungry aftermarket appliances that might tax a one battery system during an ESS event, so fast, that by the time the ESS event early terminates due to battery voltage drop, the battery lacks the power to crank the engine.

A better system would have involved equally sized dual batteries, perhaps ones that switch off playing the role of Aux and main battery, but that's not only pricey, it's a feature the vast majority of owners don't want to pay for, and that for those who do, Stellantis knew the aftermarket would come thru, to wit: Genesis Offroad.

 

[Chupacabra]

Stellantis couldn't design their ESS system with one battery like so many other vehicle manufacturers who don't, unlike Stellantis, have to content with so many JL owners adding too many energy hungry aftermarket appliances that might tax a one battery system during an ESS event, so fast, that by the time the ESS event early terminates due to battery voltage drop, the battery lacks the power to crank the engine.

My boss had a Cherokee that had the same problem, the ASS system rarely worked. He took it in multiple times and they of course couldn't fix it. Cherokee owners aren't generally the kind to heap a bunch of other electrical geegaws on their vehicles I don't think. AFAIK, it also had this stupid two-battery system.

He replaced that Cherokee with a new Bronco, with a ton of Aux switches and extra crap on it including a winch. Guess what, it has one battery and ASS works flawlessly on it and has worked fine for the last two years he's owned it.

So while your reasoning for having two batteries makes sense, in the real world it just doesn't seem necessary and adds complexity and failure points to a system that doesn't need it. Jeep's poorly designed ASS system is probably the cause of more complaints about Jeeps than anything else.

I've just given up on it ever working right. I will sometimes top off my batteries with the NOCO and it'll work for a month or so, then quits again.

 

[TheNewGuy]

I will check for that this evening, thanks!

No need to go looking for it.
A device like the SmartStopStart or Auto Stop Start Eliminator does not disable the ESS!!! It only makes the button on the dash into a "smart" button so it remembers the setting prior to the Jeep being shut off. All it does is eliminate the need to keep pushing the button.

 

[HipCheck]

James: just in the need of ruling out things, is it correct to say that you don't see, in the dash (i.e. the EVIC) an icon near the "E" (as in fuel empty letter,) that appears as the capital letter "A", with a near circle around it, followed by an exclamation point?

This would be a sign that the vehicle has turned off the ESS system for you. A situation where this might happen in dual AGM battery JLs, like your model year's, is where upon attempting to cold crank, the standard test of the ESS battery (alone) jut prior to cold crank fails, as does the crank attempt, but the subsequent crank attempt succeeds.

In all but the earliest of 2018 dual AGM battery JLs (which won't start with a dead ESS battery barring a software upgrade) a dead ESS battery (in dual AGM battery JLs) causes the first attempt to crank to fail, where subsequent attempts to crank go only against the main battery, and if successful, engage this aforementioned dash light, where all future cold cranks happen on the first try, only against the main battery, until such time, if any, at the cold crank after the ESS battery is replaced with an energized one, or one of the battery bypass hacks common in this forum is employed.

I have a 2018 JLU and this (likely) happened to me recently. Had to jump it. The ESS light was on, on the dash. Happened one more time (the same day). Then never again. Says stop start is unavailable, but Jeep runs fine. I'll never replace that second battery on my own.

 

[jfisher]

No need to go looking for it.
A device like the SmartStopStart or Auto Stop Start Eliminator does not disable the ESS!!! It only makes the button on the dash into a "smart" button so it remembers the setting prior to the Jeep being shut off. All it does is eliminate the need to keep pushing the button.

Ah, that's not it then. I can't physically get the stop / start to ever operate in any condition.

 

[jfisher]

I have a 2018 JLU and this (likely) happened to me recently. Had to jump it. The ESS light was on, on the dash. Happened one more time (the same day). Then never again. Says stop start is unavailable, but Jeep runs fine. I'll never replace that second battery on my own.

Good to know. It doesn't say stop start unavailable on ours though. Weird.

 

[Bandit59]

The wife recently picked up a 2022 JLU Sahara about 5-6 weeks ago. 29k miles, 2.0. One thing we've noticed is that the auto stop / start isn't functional (I'm not complaining, but it is odd). You can push the button and it lights up like normal, but it doesn't actually do anything and the Jeep never auto stops / starts at any point no matter whether the button is pushed or not. I've looked into several things (wearing seatbelt, sensor under hood, etc), but none check out. Anything else to check to make sure there isn't something physically wrong?

If no cel or message. I would think it has a stop start eliminator. Under your dash. Nothing wrong with this

 

[TheNewGuy]

If no cel or message. I would think it has a stop start eliminator. Under your dash. Nothing wrong with this

No need to go looking for it.
A device like the SmartStopStart or Auto Stop Start Eliminator does not disable the ESS!!! It only makes the button on the dash into a "smart" button so it remembers the setting prior to the Jeep being shut off. All it does is eliminate the need to keep pushing the button.

 

[Chiprtom]

2019JL. Mine recently stopped working and I get a alert on the dash saying it needs to be serviced.

 

[AndySpill]

I have a 2018 JLU and this (likely) happened to me recently. Had to jump it. The ESS light was on, on the dash. Happened one more time (the same day). Then never again. Says stop start is unavailable, but Jeep runs fine. I'll never replace that second battery on my own.

All dual AGM battery JLs, upon operator attempt to cold crank them, will for an instant separate the two batteries, normally connected in parallel but for this instant and ESS events, to test the ESS battery in isolation prior to attempting the crank.

If it fails, the earliest of 2018s won't crank. This can be resolved by having TSB 18-092-19 applied to the vehicle by a dealer: it's functionality built into all later year 2018s and beyond. The jump start procedure has us connecting a power source, and being more patient than on other vehicles before attempting the crank because (without the owner's manual saying so much) that power source is charging the ESS battery enough to pass the pre crank test, which will isolate the ESS battery from no simply the main battery, but those jumper cables connected (at least the positive) to the positive terminal on the main battery.)

This modification causes the same described behavior, but the second attempt to crank is attempted solely against the main battery. If successful, the ESS off like in the dash (not the light in the manual ESS button) is illuminated and all subsequent cranks should be successful on the first attempt, going against, and provided the main battery has ample power.

Only upon reintroduction of an energized ESS battery, or incorporation of one of the techniques to bypass this ESS battery well discussed on this forum, will that light in the dash get turned off.

 

[five9dak]

You're better off. ASS is just shortening your engine life to save a few pennies in gas and making you look like tosser at every stop light when we hear your jeep turn off and back on.

 

[HipCheck]

Only upon reintroduction of an energized ESS battery, or incorporation of one of the techniques to bypass this ESS battery well discussed on this forum, will that light in the dash get turned off.

Great summary. The only thing is AFTER the 1st jump, the ESS light on the dash came on. The NEXT jump, the Jeep started and the light stayed off. Never illuminated again. Stop start message is constant.

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