AutoZone/O'Reilly and Aux Battery

[AZHellaYellaGirl]

Hi hi!

My Start Stop Not Available sensor came on in my 2021 Sport Altitude 2.0L that I just purchased used from a private dealer. Needless to say, I did NOT purchase their warranty, so now the sensors of course are appearing haha.

Upon research in the forums and on google, sounds like this sensor and error message (the Circle A with Exclamation Point) is most likely the Aux battery. Since the vehicle is used, who REALLY knows what battery life is left, you know?

Can I just have AutoZone or O'Reilly test the Aux Battery and I can purchase to have installed there? Or would I need to pay the atrocious costs of my local Jeep dealer (private dealer rates are through the roof, even though I did purchase from there, and their shop isn't as extensive) to have this done?

This is my first Wrangler...in all of my other cars, there was only 1 battery so I always just had them do it (it's 1000 degrees here in Arizona, nobody wants to work outside haha if they can avoid it on their vehicle, myself included).

Any assistance is appreciated!

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[Radioman]

Hi hi!

My Start Stop Not Available sensor came on in my 2021 Sport Altitude 2.0L that I just purchased used from a private dealer. Needless to say, I did NOT purchase their warranty, so now the sensors of course are appearing haha.

Upon research in the forums and on google, sounds like this sensor and error message (the Circle A with Exclamation Point) is most likely the Aux battery. Since the vehicle is used, who REALLY knows what battery life is left, you know?

Can I just have AutoZone or O'Reilly test the Aux Battery and I can purchase to have installed there? Or would I need to pay the atrocious costs of my local Jeep dealer (private dealer rates are through the roof, even though I did purchase from there, and their shop isn't as extensive) to have this done?

This is my first Wrangler...in all of my other cars, there was only 1 battery so I always just had them do it (it's 1000 degrees here in Arizona, nobody wants to work outside haha if they can avoid it on their vehicle, myself included).

Any assistance is appreciated!

I'm going to assume from your post that you don't have the knowledge and/or tools to replace the batteries yourself. If they are original batteries, they are probably due to be replaced, especially with the heat of AZ. The AUX battery is located on the firewall below the fuse box and is not visible looking under the hood. Only by separating the leads from the main battery (negative side) can the AUX battery be tested. Maybe your local auto store is willing to go to that effort, that is an unknown but I would bet that they are not willing to change out the AUX battery. (I could be wrong, you need to ask). If you do have tools available, there are various videos that show how to change the AUX battery. Alternately, you could just remove the negative lead of the AUX battery and remove fuse 42 and abandon the AUX battery in place. Then just deal with the main battery.

 

[AZHellaYellaGirl]

I have some of the knowledge, but not the tools or a place to perform it that is not in direct sun. These last weeks it has gotten back up to highest 90's into the 100's again, and I just really don't want to be in the sun trying to do an Aux battery swap when I don't really know what I'm doing on that one.

I can ask for sure, but wasn't sure if anyone had already done that and had experience working with their auto store doing it.

 

[ssls6]

I just got back from Kauai. I always rent jeeps when I'm there and this trip was pretty funny. The first jeep they gave me had the start stop error message on the dash and a "change oil now" message. I brought the jeep back and they gave me another (this time a rubicon). While I was waiting, another couple came in because their 2nd jeep would not start (battery issues) after a day of island touring. That couple was pissed off being forced to get towed back to Budget for a 2nd time LOL. Basically, the 2 battery system of the jeep JL was causing big issues for Budget rental cars.

On my own Jeep JL rubicon here in CO, I have replaced both batteries and added the start/stop eliminator. I just found it funny that the rental fleet was leaving such a bad taste in the mouths of renters who just wanted the jeep experience while on the island.

As for the original topic, I bought my aux battery from O'reilly. It was a 200 CCA AGM, the Mopar I replaced was a 160 CCA AGM.

 

[mwilk012]

Please stop saying sensor.

A sensor is a device used to detect a parameter of some sort. The word you're looking for is "light". A bunch of warning lights came on.

Absolutely no parts store will install an aux battery for you.

 

[AZHellaYellaGirl]

Well, it was 1 warning light that stays, and one message when I start my Jeep, but yes. Apologies for the terminology error. Not a vehicle newbie by any means, just used the wrong term for the moment.

Appreciate the response and I’ll look for other options of less expensive than dealer battery installs once I have it tested.

Thanks!

 

[Vanburi]

Do some more reading here.
Many battery threads about bypassing or disabling the aux battery with no ill effects.

 

[Radioman]

Well, it was 1 warning light that stays, and one message when I start my Jeep, but yes. Apologies for the terminology error. Not a vehicle newbie by any means, just used the wrong term for the moment.

Appreciate the response and I’ll look for other options of less expensive than dealer battery installs once I have it tested.

Thanks!

No need to apologize. Most of us are eager to help people new to Jeep, even if some items are not "correctly" described.

 

[Valpo Jeep]

I would not let the average Autozone worker even change my wiper blades to be honest. Replacing the Aux battery can be done at just about any automotive shop but plan to spend a few hundred on labor. I think the official route to the aux battery is from the top so they have to take the fuse box off, the better route is to open the fender liner and remove the battery from below.

 

[mwilk012]

I would not let the average Autozone worker even change my wiper blades to be honest. Replacing the Aux battery can be done at just about any automotive shop but plan to spend a few hundred on labor. I think the official route to the aux battery is from the top so they have to take the fuse box off, the better route is to open the fender liner and remove the battery from below.

No, the correct route is by removing the fender liner. That is the only published official procedure.

 

[engineXI]

1) please never use google for any reason ever. its for the sake of humanity
2) you can change that battery if you want to.
3) get a tazer and disable start/stop

 

[mwilk012]

1) please never use google for any reason ever. its for the sake of humanity
2) you can change that battery if you want to.
3) get a tazer and disable start/stop

If you google “will autozone change my aux battery”, you get this thread as a top result.

Expecting some random person to be able to change their aux battery is naive at best, dangerous at worst. If they don’t have the confidence and the prerequisite skills, the best advice is just the name of a shop that will help.

 

[AZ Hella]

The answers to all of your future battery issues are contained here.
https://www.jlwranglerforums.com/forum/threads/jumperless-aux-battery-bypass.95945/

 

[AndySpill]

@AZHellaYellaGirl

Hi Danica:

Apologies for regurgitating some things already said, some not.

At your attempt to cold crank your engine (i.e. not a warm engine crank after an engine start top event ESS), the JL will, for an instant, seek to isolate your Aux battery and test its power. If this test is passed both batteries are reconnected in parallel (positive post to positive post, negative to negative) to crank the engine from both batteries.

At some point I will guess this Aux battery's voltage no longer met a minimum threshold and your JL would not crank.....so you tried again and this time, as is the case for all but the earliest of 2018s, the second crank attempt, which happened against solely the main battery, was successful. In response, your vehicle turned on the ESS off light preventing ESS events from occurring: a smart thing considering that such events run solely off the Aux battery which is likely, in your case, "shot."

Future cranks will continue on the first attempt against the main battery and that light is going to stay on until the sooner of you replacing that Aux battery or bypassing it.

The question now becomes, do you want to run ESS events and are you willing to pay for the cost for this Aux battery, as well as a main battery, including installation?

You see, because the two batteries are always in parallel but for ESS events and this instant at cold crank, one bad battery can often negatively effect that other battery, and when one battery goes, regardless of which, the main battery is suggested to be replaced as well.

As mentioned, your Aux battery can be tested by putting the tester's leads on the main (that's right I said main) battery's positive terminal and the disconnected cable that is normally on the main battery's negative terminal, whose distal end connects to the negative post of the Aux battery. To this point two factory cables connect to the main battery's negative terminal. One of those cables has as its distal end the body ground connection on the passenger's side front panel and should be left connected. It's the other cable you disconnect to test the Aux battery.

Make sure that disconnected cable doesn't come into contact with any vehicle metal surface.

Still more, the testing that needs to be done is effected with a load tester, not simply a multimeter that tests voltage. A load tester tests the battery's ability to deliver charge: i.e. that which a battery is suppose to do.

If the Aux battery is "shot" and you don't care to spend the money to replace it, and/or don't desire to run ESS events, you can tape up this cable's end that I just had you pull, and as mentioned above, yank Fuse 42 from the Power Distribution Center (PDC) (i.e. the intelligent fuse box, black in color on the passenger's side near the top of the engine bay area.)

Yanking this fuse will prevent the batteries from ever being isolated, and calls for electrical current to just the Aux battery will instead go to all batteries, of which only the main battery remains connected. Fuse 42 energizes something called the Power Control Relay (PCR) that when provided with electrical current separates the two batteries. Under factory conditions the PCR is energized during ESS events and an instant at cold cranking. Removing this fuse is a silent operation: your JL none the wiser. It should turn off that ESS off light in the dash because the pre cold crank test will now be effected against the main battery, where ample power is found.

I would suggest that you do not run ESS events with just the main battery as doing so could in theory rob it of cranking power at the conclusion of an ESS event considering that the aforementioned fuse pull will run such ESS events only off the main battery. Please push the ESS off button or buy aftermarket tech to do this for you.

Even if you do without ESS events and the Aux battery they run on, I'd load test the main battery by moving the tester's negative lead to the main battery's negative terminal while this aforementioned cable is disconnected. I'll bet the main battery is due for a change as well.

If you want ESS events replace both batteries and keep Fuse 42 in place.

 

[Nitehawk92]

Well, it was 1 warning light that stays, and one message when I start my Jeep, but yes. Apologies for the terminology error. Not a vehicle newbie by any means, just used the wrong term for the moment.

Appreciate the response and I’ll look for other options of less expensive than dealer battery installs once I have it tested.

Thanks!

No biggie on the terminology, just don't put an angry grille on your Jeep and you will be fine in this forum...

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