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New battery, now it won’t start or turn off

JlNewb

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2018 sport died at a light. Pushed it to a parking lot, I’m posting while waiting for a tow.

I got a jump, it ran but wouldn’t drive, said it was going to power off. Got a new battery, dropped it in, engine started twice but died immediately afterwards. Wouldn’t turn off. Cycle on the dash display with a battery icon, complaining the car is not in Park (it is), to lights off, then starts over again. Disconnected the battery and the cycle has continued for the last half hour, down to just a flicker now.

Any bets on what is wrong?
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Rhinebeck01

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2018 sport died at a light. Pushed it to a parking lot, I’m posting while waiting for a tow.

I got a jump, it ran but wouldn’t drive, said it was going to power off. Got a new battery, dropped it in, engine started twice but died immediately afterwards. Wouldn’t turn off. Cycle on the dash display with a battery icon, complaining the car is not in Park (it is), to lights off, then starts over again. Disconnected the battery and the cycle has continued for the last half hour, down to just a flicker now.

Any bets on what is wrong?
@JlNewb

Well, your 2018 3.6 has 2 batteries not one. You apparently replaced the Main battery only and not the Aux battery that resides under the PDC (Power Distribution Center) that is apparently dead/depleted . Since you have a 2018 your JL will not start on second try like with the 2019-2021 JL... this is why your JL is dead in the water so to speak.

IF, you can't get it out of Park for your flat bed tow (must be flat bedded!) read here:

Jeep Wrangler JL New battery, now it won’t start or turn off yy.JPG
 
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JlNewb

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Aux battery under your main battery! when one goes they usually both have to be replaced.
That would explain why the AC was still running but the car wouldn’t start. Damn, wish I’d known about that at the auto store.
 

txj2go

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If you have a 2018 that hasn't had a flash update, then there are ways that you can disconnect and bypass the small battery and the car will run just fine. There are threads here discussing this, very long threads. Maybe if you search for "jumper wire" you can find the right place to start reading. Actually I believe if you add the jumper wire then the Jeep would run right now without messing with the small battery.

My 2018 has had the flash so I was able to bypass the small battery without needing a jumper and mine runs just fine.
 

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Rhinebeck01

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That would explain why the AC was still running but the car wouldn’t start. Damn, wish I’d known about that at the auto store.
@JlNewb

Read here:
https://www.jlwranglerforums.com/fo...ent-the-easy-way-pull-the-fender-flare.56807/

For Aux battery buy:
DieHard Platinum AGM Battery, BCI Group Size 400, 200 CCA
Part # AUX14-1

Super Start Platinum Auxiliary Battery Group Size 400
Part #AUX14

Your JL's CEL will clear after you replace the Aux, and have a charge on your Main battery
 

Rhinebeck01

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If you have a 2018 that hasn't had a flash update, then there are ways that you can disconnect and bypass the small battery and the car will run just fine. There are threads here discussing this, very long threads. Maybe if you search for "jumper wire" you can find the right place to start reading. Actually I believe if you add the jumper wire then the Jeep would run right now without messing with the small battery.

My 2018 has had the flash so I was able to bypass the small battery without needing a jumper and mine runs just fine.
@txj2go

IF, your 2018 JL has had TSB 18-092-19 (Power Control Update) applied to it as you say..... then... as long as your Main battery is charged sufficiently, your JL will start on the second try even if the Aux battery is depleted. Yes, when your JL starts you will see the EVIC light go on, but once you batteries both are up to snuff, (replaced/charged sufficiently) the light will go out automatically. The preceding is why all 2018 owner's should have tthe TSB applied to their JL/JLU.
 

gato

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@JlNewb
IF, you can't get it out of Park for your flat bed tow (must be flat bedded!) read here:
Slightly off topic but a couple of questions on this....

1 - Why can't you simply put the transfercase in N for a tow truck?

2 - Why does it have to be flat bedded, given that Jeeps are pulled as TOAD vehicles behind motorhomes all the time, sometime 4-wheel toad, sometime two wheels down on a dolly?

(I'm just asking - really curious about the answer)
 

Rhinebeck01

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@gato

If you tow with either just front or just rear off ground, you risk transfer case damage and more. Even if transfer case is in N. No risk if you just flat bed it as recommended by the owner's manual.

Yes, you see JK's and JL's used as TOAD's all the time.... Flat Towing with all 4 on the road.... No problem doing that.

You do not see JK's and JL's being routinely towed with either just front or rear wheels on a dolly. Sure, doable but you have to have a clue so to speak..

Here is a thread that you might read for thoughts on this..

https://www.jlwranglerforums.com/forum/threads/why-does-jeep-not-recommend-tow-dolly.59873/#:~:text=Recreational towing, like with an,if you're really worried.
 

aldo98229

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Apparently it is a characteristic of modern vehicles with so many electronics, when the battery starts to fail, instead of becoming gradually reluctant to start, as it was in the past, new vehicles start giving you “misinformation”. I.e., warnings like the ESS is not available, the transmission or transfer case is not shifted into gear, CEL, etc.

My Jeep started acting up a month ago. First the CEL came on and went away; then the ESS light; the Selec-Trac would slip out of 4A. It went on for 2 or 3 weeks like this. It was all erratic and sporadic. I thought there was something wrong with the Jeep. A week ago the start button would refuse to work on first try but work on second try; the speakers started to pop. That’s when it became obvious that it was the batteries.

Last week I replaced both batteries and everything is now back to normal.

The problem is these symptoms are disconcerting; they prompt the average owner to take the Jeep into the dealer.

Judging by posts out there, instead of simply replacing the batteries, half the time dealers spend WEEKS chasing the electronic gremlins, often requiring multiple visits to the dealership, sometimes on the back of a tow truck. They end up not only wasting time, but undermining customers’ trust in their Jeeps.
 
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txj2go

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Apparently it is a characteristic of modern vehicles with so many electronics, when the battery starts to fail, instead of becoming gradually reluctant to start, as it was in the past, new vehicles start giving you “misinformation”...
I haven't experienced much of this because I'm typically proactive and replace my batteries before they fail. Driving my car every day in the hot south, with the battery in the engine bay, my batteries would barely last 36 months. After a number of batteries failing like this in multiple different vehicles I got wise and replace them at least by 36 months. (These are flooded acid batteries.)

Then the first monkeywrench in my plans- my wife got a GMC Acadia that does not have the battery in the engine compartment so the battery stays cooler. That flooded acid battery lasted 60 months. My daughter's Grand Cherokee had the battery not in the engine compartment so its battery lasted 60 months. That isn't enough history to tell for sure but around 60 months I might consider replacing those batteries.

Then the second monkeywrench in my plans- I got the JLU with AGM battery. AGM batteries are said to last twice as long as flooded acid batteries. So does that mean my plan would be to replace at 72 months? In my 2018 JLU I replaced the factory battery this spring because I was going to be taking some trips to remote places and I didn't want to rely on the old original battery. And I bought the best AGM I could buy. Now I'll just have to watch to see how long it lasts but I should have good peace of mind for at least a couple of years anyway.
 

dsgrey

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My Miata had a Panasonic AGM in the trunk that lasted 9 years and I had a wet cell on my riding lawnmower that lasted 6 years. Every other battery I've owned usually dies at 2 - 3 years regardless of the name stamped on the side. Load test them and plan on replacing soon once they drop below 100% of stated amps. Plus carry an ESS bypass cable.
 

Jebiruph

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For the OP's problem, I say blown ESS fuse (N3) which isolates electronics from the main battery, so new main battery won't help. It also isolates the aux battery from the alternator, the Jeep continues to run until aux battery runs down.
Jeep Wrangler JL New battery, now it won’t start or turn off underhood N3 short.PNG
 

txj2go

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For the OP's problem, I say blown ESS fuse (N3) which isolates electronics from the main battery, so new main battery won't help. It also isolates the aux battery from the alternator, the Jeep continues to run until aux battery runs down.
It would be simple to externally jumper N2 and N3 to see if this makes a difference.
 

gato

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Apparently it is a characteristic of modern vehicles with so many electronics, when the battery starts to fail, instead of becoming gradually reluctant to start, as it was in the past, new vehicles start giving you “misinformation”. I.e., warnings like the ESS is not available, the transmission or transfer case is not shifted into gear, CEL, etc.
I see two related issues in the JL:

1 - The use of two batteries with an overly complicated and fail-prone system for ESS. (and bad programming in the 2018 models unnecessarily preventing a start with a good main battery)

2 - Not having a simple voltage test and simply report "Main Battery low voltage" or "Aux Battery low voltage" errors. This may likely be related to #1 (the complexity). Clearly if there is enough power for the display computer to put messages on the screen, it should be possible to read the voltage and display a correct error.
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