ESS light came on after having key fob programmed

[Butch15]

So I took my 2019 Sahara to the dealer to pick up a spare key that I had ordered 6 weeks ago and get it programmed. I got about 3 miles away from the dealer when the dreaded ESS warning light came on in the instrument cluster. Drove straight back to the dealer because it had never happened before. Service advisor said they are replacing the aux battery (for free) but I will need to drive it for awhile for the computer to relearn everything (shift points etc) Is this correct? Should I replace the main battery at the same time to avoid any further issues? FYI this Jeep is bone stock, 49k mile and I’ve only owned it for 2 months. Jeep only came with one key, otherwise it never would have been in a dealership service department. I have a good mechanic that I’ve been using for over a decade….my mechanic did a thorough pre-purchase inspection before I bought it.

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[jludave]

Service advisor said they are replacing the aux battery (for free) but I will need to drive it for awhile for the computer to relearn everything (shift points etc) Is this correct?

It’s possible if the vehicle was without power for a while.

Should I replace the main battery at the same time to avoid any further issues?

Yes. Always replace both, unless you plan on bypassing the aux.

 

[Butch15]

It’s possible if the vehicle was without power for a while.



Yes. Always replace both, unless you plan on bypassing the aux.

Thanks for the input.
Service manager wouldn’t admit to disconnecting battery or even that it was related to the programming key fob, but did replace the aux battery for free as a “goodwil” gesture (including labor). I will replace the main battery tomorrow after work and kick the can down the road as far as bypassing the aux battery.

 

[AndySpill]

For the same or nominal addition cost, owners who have stock H6 size batteries can take the opportunity when replacing that battery to get a slightly beefier H7 battery. I recommend that your replacement main battery with a H7 type battery regardless of whether the old one is an H6 or H7.

https://www.jlwranglerforums.com/forum/threads/main-battery-replacement-talk-jl-jt.100534/

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