The infamous start/stop aux battery

[Grasshopper]

Here’s the nutshell: Jeep needed a jump, main battery needed replacing, did that but still seeing this. Personally, I’m glad it’s not working cause I manually pushed the button to turn it off anyways - however, I’m assuming this is still showing cause there’s an issue with aux battery? Been driving for weeks with this but wondering, should I replace aux battery or look into a delete? And if you’ve done the delete, what kit do you recommend and has it been working out for you?

Ive read lots of posts but it’s hard to get consistent info.

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[dayusmc]

There are several reasons you could be getting that message, not just the AUX battery. But you could always pull the fuse and see. Do a search, I can't remember what fuse it is...

 

[PuddleJumper]

Here’s the nutshell: Jeep needed a jump, main battery needed replacing, did that but still seeing this. Personally, I’m glad it’s not working cause I manually pushed the button to turn it off anyways - however, I’m assuming this is still showing cause there’s an issue with aux battery? Been driving for weeks with this but wondering, should I replace aux battery or look into a delete? And if you’ve done the delete, what kit do you recommend and has it been working out for you?

Ive read lots of posts but it’s hard to get consistent info.

any vehicle with dual batteries. odds are they will both be on thier way out at the same time. If you didn't get the AUX tested to prove its still good. odds are its bad, and its gonna drain on your new battery and screw it up too eventually. Common practice on these trucks is to get a new AUX and Main, charge both to full capacity outside of the vehicle and then install.

 

[Mr._Bill]

The most likely reason for the message is the Aux battery failing the startup test. Unless it failed in a dead state, it is a drain on the Main battery. As mentioned, both batteries should be replaced at the same time. If you are concerned about warranty, replace the Aux battery. If not, there are plenty of posts on how to delete it. Removing the Aux Battery does not disable ESS. You will still need to turn it off at each startup, or install something like the Smart Stop Start device to do it for you.

 

[Brahmajoe]

Here’s the nutshell: Jeep needed a jump, main battery needed replacing, did that but still seeing this. Personally, I’m glad it’s not working cause I manually pushed the button to turn it off anyways - however, I’m assuming this is still showing cause there’s an issue with aux battery? Been driving for weeks with this but wondering, should I replace aux battery or look into a delete? And if you’ve done the delete, what kit do you recommend and has it been working out for you?

Ive read lots of posts but it’s hard to get consistent info.

What does the voltage show at idle?

 

[sharpsicle]

So many questions that need answering here:

1. What was the determining factor that the main needed replacing?
2. Was the aux tested at that time?
3. How was this testing performed?
4. Was the main battery charged prior to install?
5. Was the IBS reset after install?
6. Have you attempted to read ant DTCs? If so, what are they?
7. What have you looked at so far? Fuses? Connectors? Wiring?

A delete might not help you. I'd work the problem first, then consider a delete once you know everything is working properly.

 

[FloridaMan655321]

I'm getting the same alarm, have been for a month. I'm planning on changing both the batteries with my next oil change. I'm in FL, so no real cold temps to leave me stranded like when I lived up north, but I should get it done earlier than later. I always disable the (very stupid) ESS, so this hasn't impacted me as far as that goes.

 

[DBravo]

Here’s the nutshell: Jeep needed a jump, main battery needed replacing, did that but still seeing this. Personally, I’m glad it’s not working cause I manually pushed the button to turn it off anyways - however, I’m assuming this is still showing cause there’s an issue with aux battery? Been driving for weeks with this but wondering, should I replace aux battery or look into a delete? And if you’ve done the delete, what kit do you recommend and has it been working out for you?

Ive read lots of posts but it’s hard to get consistent info.

As others have mentioned, the Stop/Start unavailable message can be caused by a number of factors. We have all just heard so much about aux battery issues, I myself jumped to that conclusion. If you have an OBD2 scanner/code reader, check for other codes. I had a cam phaser sensor issue that was making the Aux stop/start system unavailable.

 

[Lunentucker]

There's no need for a kit of any kind.

You can bypass the aux battery easily by...
1. disconnecting the aux ground at the main ground group
2. wrapping the cable to prevent incidental grounding
3. zip tying it out of the way
4. Removing fuse F42
ESS will still function as normal, but using just the main battery.
You can disable it using a third party device like Tazer or Auto Start Stop Eliminator, or you can learn to press the button on the dash. You can lay down the outermost hood switch plunger and it will not function, but the light will still come one on the dash.

Here's the video I made on the bypass procedure. Ignore the part about it saying that ESS will be disabled. That was wrong.
I did this last July, and there have been zero issues.




You can do a full delete, but that's more involved.

 

[56cbr600rr]

Same exact happened to me last week when out of town on vacay. Jumped it. Started right up. Had the same code. Drove it 3 days, nothing……. Pulled the IBS plug 15 minutes. In a day the sevice light went away. All good.

 

[ShadowsPapa]

That says service - not battery charging. So it could be any number of things.
Already been said people jump up and down over the aux battery - do what you want but the huge, vast, majority of all Jeeps out there with this system do just fine IF people properly diagnose things (like the batteries) and replace them when needed.
Either battery can go first.
Here's the thing - this exact same system has been on hundreds of thousands of Grand Cherokees for 8 years........... and yet....... who is jumping (mostly to conclusions) - Wrangler/Gladiator owners. Why? Because the DIYers always know better than anyone else.
How many Grand Cherokees with the 3.6 have been sold 2016 model year to current?
Same system.
We've had at least 3 of those, plus my 2 Gladiators. Stock electric systems. We had batteries (both) go bad when our 2018 was 3 years old, just 4 weeks inside of warranty - no being stranded, simply jump start it properly, good to go. Batteries replaced, it was fine. (I used a cheap jump pack to jump it a couple of times)

 

[Lunentucker]

 

[Trollboogie]

Mine was a bad hood pin switch that caused that light.

 

[Grasshopper]

That says service - not battery charging. So it could be any number of things.
Already been said people jump up and down over the aux battery - do what you want but the huge, vast, majority of all Jeeps out there with this system do just fine IF people properly diagnose things (like the batteries) and replace them when needed.
Either battery can go first.
Here's the thing - this exact same system has been on hundreds of thousands of Grand Cherokees for 8 years........... and yet....... who is jumping (mostly to conclusions) - Wrangler/Gladiator owners. Why? Because the DIYers always know better than anyone else.
How many Grand Cherokees with the 3.6 have been sold 2016 model year to current?
Same system.
We've had at least 3 of those, plus my 2 Gladiators. Stock electric systems. We had batteries (both) go bad when our 2018 was 3 years old, just 4 weeks inside of warranty - no being stranded, simply jump start it properly, good to go. Batteries replaced, it was fine. (I used a cheap jump pack to jump it a couple of times)

I really love this answer haha thanks, you've got a great point

 

[RHINO79]

There's no need for a kit of any kind.

You can bypass the aux battery easily by...
1. disconnecting the aux ground at the main ground group
2. wrapping the cable to prevent incidental grounding
3. zip tying it out of the way
4. Removing fuse F42
ESS will still function as normal, but using just the main battery.
You can disable it using a third party device like Tazer or Auto Start Stop Eliminator, or you can learn to press the button on the dash. You can lay down the outermost hood switch plunger and it will not function, but the light will still come one on the dash.

Here's the video I made on the bypass procedure. Ignore the part about it saying that ESS will be disabled. That was wrong.
I did this last July, and there have been zero issues.




You can do a full delete, but that's more involved.

Excellent explanation !!!

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