Another start stop issue Could it still be battery related

[birddog2!]

Vehicle
2020 Jeep Gladiator
History:
last march start stop stopped working - didnt pay attention to it because I was happy - only to find it was a battery issue (Learned the hard lesson after reading all the posts here).
So replaced both batteries - went through the process - everything fine after that until three days ago.

This time though there are no warnings in the start stop screen or anything

what is happening though when ideling and the stop engages, when I release the break all accesories dim , the truck starts but has that battery about to die sound and slow crank and then starts, everything comes back to life but the auto park engages. so have to go to park and then back to drive.

batteries after sitting all night test at 12.26 and with the engine running goes to 14.3 on the dash monitor - 14.6 on the multimeter

batteries are a year and a half old
main -
ACDelco Gold 94RAGMHR 36 Month Warranty High Reserve AGM BCI Group 94R Battery

aux
ACDelco Gold AUX14-200 36 Month Warranty Auxiliary AGM 200 CCA Battery


no error codes, no other obvious issues going on

Checked the two hood sensors - they seem fine - operate as they should swapped them around - no difference

Wondering if anyone else experience the auto park feature engaging after a sluggish start and what to look for

Thanks for any input

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[birddog2!]

An additional note
The battery reading of 14.3 is sitting in the driveway running
Actually driving the on board voltage reads up and down from 13.2 to 13.8

Guessing alternator is on the way out at this point.

 

[Commodus]

Vehicle
2020 Jeep Gladiator
History:
last march start stop stopped working - didnt pay attention to it because I was happy - only to find it was a battery issue (Learned the hard lesson after reading all the posts here).
So replaced both batteries - went through the process - everything fine after that until three days ago.

This time though there are no warnings in the start stop screen or anything

what is happening though when ideling and the stop engages, when I release the break all accesories dim , the truck starts but has that battery about to die sound and slow crank and then starts, everything comes back to life but the auto park engages. so have to go to park and then back to drive.

batteries after sitting all night test at 12.26 and with the engine running goes to 14.3 on the dash monitor - 14.6 on the multimeter

batteries are a year and a half old
main -
ACDelco Gold 94RAGMHR 36 Month Warranty High Reserve AGM BCI Group 94R Battery

aux
ACDelco Gold AUX14-200 36 Month Warranty Auxiliary AGM 200 CCA Battery


no error codes, no other obvious issues going on

Checked the two hood sensors - they seem fine - operate as they should swapped them around - no difference

Wondering if anyone else experience the auto park feature engaging after a sluggish start and what to look for

Thanks for any input

Your voltages look normal but you need to test them individually May still be one of your batteries can’t say but I never had good results with Delco. The system should prevent an ESS from happening if a battery is not fully charged but I have seen batteries with a shorted cell that can cause all types of problems

 

[ShadowsPapa]

Batteries can go bad at any age - even only months old.
Did you fully charge each battery before installing?
What are the battery voltages with the truck off - using a volt meter, not the dash?

First, check all connections thoroughly - not just looking, but grab them and pull and try to wiggle them.

 

[birddog2!]

Turned out to be the main battery.
Prices on everything going up and quality going down - sad.

 

[birddog2!]

Your voltages look normal

The more I read I learned that alternators are very different now haha so under the assumption that the stop part of the start stop was fuction correct - it was the start that threw it into auto park - doing a crank test the main battery dropped to 8.6V - replaced it drove around the start stop functioned correct 7 times - so calling it a win for today but wont be surprised if that changes in a few days ... we will see.

 

[Charly_Mojave]

Hi Guys I got my Mojave 2023 and I got the same issues related to the batteries, the dealer already changed both batteries the auxiliary first and a couple of weeks the main but still the problem remains, anyone for here know what the root cause really is?

 

[ShadowsPapa]

Hi Guys I got my Mojave 2023 and I got the same issues related to the batteries, the dealer already changed both batteries the auxiliary first and a couple of weeks the main but still the problem remains, anyone for here know what the root cause really is?

Same issues? EXACTLY? So we don't have to go back and read a whole thread - what is the problem on YOUR Jeep?
If they did not fully charge the batteries BEFORE putting them in the vehicle and reset the IBS afterwards, then that could be a problem, they may have blown a fuse............ rather not read a whole thread to find out what your specific issue is.

 

[Charly_Mojave]

Same issues? EXACTLY? So we don't have to go back and read a whole thread - what is the problem on YOUR Jeep?
If they did not fully charge the batteries BEFORE putting them in the vehicle and reset the IBS afterwards, then that could be a problem, they may have blown a fuse............ rather not read a whole thread to find out what your specific issue is.

Hi Bill,

Here is the short version of my issue:
2023 Jeep Gladiator Mojave (3.6L).

1. The first electrical-related repair was the replacement of the front auxiliary ESS battery under warranty in December 2025.
2. A few months later I started noticing ESS-related symptoms:
   • Auto Start/Stop became inconsistent.
   • The engine sometimes struggled to restart after an ESS stop at traffic lights.
   • ESS availability gradually decreased.
3. Then I started getting the message:
   "Aux Switches Temporarily Unavailable – Battery Charging."
4. Shortly after that, I experienced a complete no-crank condition:
   • Dash powered up normally.
   • Accessories worked.
   • Engine would not crank at all.
5. I used a NOCO GB150 jump starter and the vehicle started immediately.
6. The dealer diagnosed the main battery as failed:
   • State of Health (SOH): 49%
   • Voltage: 10.44V
   • Multiple low-voltage DTCs were stored.
7. The vehicle was then kept at the dealer for an extended diagnosis. So far they have:
   • Replaced the main battery.
   • Replaced the starter motor (or starter assembly).
   • Replaced the Power Distribution Center (PDC / fuse box).
8. Before the no-crank event I had already experienced:
   • ESS becoming less available over time.
   • Slow or hesitant restarts after ESS stops.
   • Battery charging messages.

Based on NHTSA documents, Jeep forums, and the symptoms, my current suspicion is that the issue started somewhere within the dual-battery ESS system (aux battery, PCR relay, IBS sensor, battery management strategy, or a combination of those components).

The truck is still at the dealer, so I am waiting for the final repair order and root-cause determination from the dealer.

"Has anyone experienced a similar sequence where the aux battery was already replaced, then the main battery also failed and replaced, followed by a starter and PDC replacement? If so, what ended up being the actual root cause?"

Thanks a lot!

 

[Charly_Mojave]

Now they are saying this is the component involved:

what’s your opinion guys?

 

[sharpsicle]

Now they are saying this is the component involved:

what’s your opinion guys?

Could be. Honestly, they have more information than any of us, so I would defer to them.

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