Yet another aux battery delete thread question

[linuxos77]

So our 2020 JL starting giving the ESS Unavailable, Service ESS system error several months ago. The Jeep has 61k miles on it, both aux and main battery are original. I finally today got around to trying the aux delete via removing fuse 42 and pulling the negative to the aux battery (I picked the smaller cable which in the 2020 is the standalone one vs the other having the plate, the older way I'm told for the cabling). I've started/stopped the Jeep several times but the ESS error remains. Do I need to clear anything out or is this a sign the issue lies in my main battery? When I drive (and idle) the battery screen reads 14v the whole time, sitting with the engine off it reads 12.2-12.5 v. Anything else I should try before replacing the main battery?

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[Reinen]

Main and Aux are linked in parallel 99.99% of the time. If one is bad, the other is not far behind. 4 years is a good run for OEM batteries. Time to replace.

Either replace both Main and Aux at the same time, or replace Main and delete Aux. Just be aware that if you delete Aux, when your new main eventually fails the failure will leave you stranded. Having Main/Aux & ESS will give you the battery failure warning you're taking advantage of right now.

 

[Rhinebeck01]

So our 2020 JL starting giving the ESS Unavailable, Service ESS system error several months ago. The Jeep has 61k miles on it, both aux and main battery are original. I finally today got around to trying the aux delete via removing fuse 42 and pulling the negative to the aux battery (I picked the smaller cable which in the 2020 is the standalone one vs the other having the plate, the older way I'm told for the cabling). I've started/stopped the Jeep several times but the ESS error remains. Do I need to clear anything out or is this a sign the issue lies in my main battery? When I drive (and idle) the battery screen reads 14v the whole time, sitting with the engine off it reads 12.2-12.5 v. Anything else I should try before replacing the main battery?

Based on what you posted, your Main battery is in need of replacement. Replace it and you should be good to go.

Stay with the Aux bypass... and replace the Main battery. IBS Sensor will be reset. After replacing the Main there will be no need to "clear" anything..

Read here for H7 AGM batteries to chose from. Also, do read through the thread so you know how to deal with the Main battery and not blow fuse N3 on the high amp fuse array and also learn about the IBS Sensor.

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

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