2018 JLUR - Battery dead - can it boost?

[CreativeName]

Hi everyone - really confused with conflicting information being told and reading.

I have a 2018 JLUR. Was completely dead.
tried to boost it with a battery pack (400A) which was unsuccessful - https://typesauto.com/products/type...7AabPx4yO3kzUs08pMNXyoDOQRfxZnPNJU0X3geVP1l2D

issue is that the jeep is in a very awkward place in my garage and hard to get to so boosting it to get it out is ideal so I can deal with the battery.

is there a way that I can boost it with a different booster or trickle charge it back to life?

Also reading conflicting information whether I should connect to positive and negative terminals when boosting with the battery booster or positive and ground (frame).
Read boosting from a live battery (another car) is a bad idea via jumper cables

I’m getting 4.8v with the ignition off right now. Ignition basically doesn’t even turn on anymore.

appreciate any guidance or suggestions you can provide.

Thanks for your guidance.

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[AndySpill]

Hi everyone - really confused with conflicting information being told and reading.

I have a 2018 JLUR. Was completely dead.
tried to boost it with a battery pack (400A) which was unsuccessful - https://typesauto.com/products/type...7AabPx4yO3kzUs08pMNXyoDOQRfxZnPNJU0X3geVP1l2D

issue is that the jeep is in a very awkward place in my garage and hard to get to so boosting it to get it out is ideal so I can deal with the battery.

is there a way that I can boost it with a different booster or trickle charge it back to life?

Also reading conflicting information whether I should connect to positive and negative terminals when boosting with the battery booster or positive and ground (frame).
Read boosting from a live battery (another car) is a bad idea via jumper cables

I’m getting 4.8v with the ignition off right now. Ignition basically doesn’t even turn on anymore.

appreciate any guidance or suggestions you can provide.

Thanks for your guidance.

This is a bit of a potentially complex problem for the following reasons:

In the earlier model year 2018 JLs, which I am not sure if you do or don't own, if the Aux battery lacked adequate charge, the vehicle would not even attempt a crank: even if the main battery was in mint condition. You may or may not have a 2018 with this logic, and if you do, it's even possible that a dealer could have flashed the computer with TSB 18-092-19, which allows the vehicle to crank on the second try if the Aux battery is dead, but the main battery has enough capacity to crank, as is the logic for late model 2018s and beyond with dual AGM batteries.

If one or more of your batteries are shot, particular if its your Aux battery, and particularly if you have a non-flashed early 2018, a booster pack my be of little use.

As far as jump starting is concerned, whether from another vehicle or not, while the jumper cable on the JL side is best connected to a body ground, if that Aux battery can't accept charge, and you have an older 2018 as discussed, it may not even attempt a crank.

~~~~~~~~~~~~~

Let's get past the academics and on to solution to get you out of the garage. The first step is to disconnect the Aux battery and bypass it. This is done by removing from the main battery's negative post the factory cable that does NOT connect to the body ground, leaving the latter connected, and then temporary insulating that loose cable end with electric tape.

Next, you will need to take the cover off the Power Distribution Center (PDC), that black box near the battery where your fuses are located. Identify Fuse 42, remove it, and keep it in a safe place.

These actions will direct your vehicle to use only the main battery for now. Attempt to crank. If unsuccessful try again with your booster or jumper cables. If unsuccessful you will need to swap out the main battery. I suggest you go with a group H7 battery, even if your JL came with a slightly smaller group H6 https://www.jlwranglerforums.com/forum/threads/main-battery-replacement-talk-jl-jt.100534/.

If your problems are truly limited to your batteries this will get you cranked.

~~~~~~~~~~

Finally the follow up. If you don't have interest in running engine start stop events (ESS) you can leave the vehicle this way but turn off ESS at the button on the console or by after market tech to do this step for you. If you desire ESS events you'll probably need to replace the Aux battery as well https://www.jlwranglerforums.com/fo...-way-pull-the-fender-flare.56807/post-1227002 and reconnect the cable I had you disconnect, along with the reinsertion of Fuse 42, and turning ESS to the on state with the button on the console.

 

[CreativeName]

This is a bit of a potentially complex problem for the following reasons:

In the earlier model year 2018 JLs, which I am not sure if you do or don't own, if the Aux battery lacked adequate charge, the vehicle would not even attempt a crank: even if the main battery was in mint condition. You may or may not have a 2018 with this logic, and if you do, it's even possible that a dealer could have flashed the computer with TSB 18-092-19, which allows the vehicle to crank on the second try if the Aux battery is dead, but the main battery has enough capacity to crank, as is the logic for late model 2018s and beyond with dual AGM batteries.

If one or more of your batteries are shot, particular if its your Aux battery, and particularly if you have a non-flashed early 2018, a booster pack my be of little use.

As far as jump starting is concerned, whether from another vehicle or not, while the jumper cable on the JL side is best connected to a body ground, if that Aux battery can't accept charge, and you have an older 2018 as discussed, it may not even attempt a crank.

~~~~~~~~~~~~~

Let's get past the academics and on to solution to get you out of the garage. The first step is to disconnect the Aux battery and bypass it. This is done by removing from the main battery's negative post the factory cable that does NOT connect to the body ground, leaving the latter connected, and then temporary insulating that loose cable end with electric tape.

Next, you will need to take the cover off the Power Distribution Center (PDC), that black box near the battery where your fuses are located. Identify Fuse 42, remove it, and keep it in a safe place.

These actions will direct your vehicle to use only the main battery for now. Attempt to crank. If unsuccessful try again with your booster or jumper cables. If unsuccessful you will need to swap out the main battery. I suggest you go with a group H7 battery, even if your JL came with a slightly smaller group H6 https://www.jlwranglerforums.com/forum/threads/main-battery-replacement-talk-jl-jt.100534/.

If your problems are truly limited to your batteries this will get you cranked.

~~~~~~~~~~

Finally the follow up. If you don't have interest in running engine start stop events (ESS) you can leave the vehicle this way but turn off ESS at the button on the console or by after market tech to do this step for you. If you desire ESS events you'll probably need to replace the Aux battery as well https://www.jlwranglerforums.com/fo...-way-pull-the-fender-flare.56807/post-1227002 and reconnect the cable I had you disconnect, along with the reinsertion of Fuse 42, and turning ESS to the on state with the button on the console.

Thank you for this! I’m afraid that I’m the unlucky early gen 2018. I have so little clearance to get to that side of my vehicle that I have to stand on my bumper and reach over everything. And I can barely open the hood because I bought a tent lift jack that’s sitting in front of the jeep. Wish I had that magic Crystal ball to tell me to park better.
Thanks for the valuable insights here

 

[THAW]

4.8V is likely an indicator of too dead/damaged to jump or charge. In any case, your battery/batteries should be replaced.

 

[AndySpill]

Thank you for this! I’m afraid that I’m the unlucky early gen 2018. I have so little clearance to get to that side of my vehicle that I have to stand on my bumper and reach over everything. And I can barely open the hood because I bought a tent lift jack that’s sitting in front of the jeep. Wish I had that magic Crystal ball to tell me to park better.
Thanks for the valuable insights here

I presume that you'll have more space to service things once you get the vehicle out of the garage.

Should you need to pull it out with a tow vehicle this video may be useful. If you take this route do exhibit all the cautions necessary for working with a free moving vehicle, particularly as it relates to inclines and stopping.

Should you decide to replace the Aux battery as well it will be much easier to do from the front passenger's wheel well outside the garage where presumably you'll have no only more height clearance buth more width to work with. But you can though go in from above. Guidance can be found by searching for a video on Youtube entitled "HOW to Replace the Main and Auxilliary Battery on a Jeep JL Wrangler and Gladiator Truck w/o eTorque" whose link I exclude here given its author (and his forum) reported to not "play nicely in the sandbox" with this forum, or so I've been told.

Here's a video on the old 2018s and Aux battery no crank with an absent or dead Aux batterymatter

If you do not plan on running ESS events and turn ESS off, the Aux battery isn't merely unnecessary, it's a burden IMHO to maintain, increasing the likelihood of it cannibalizing a new main battery. If you go out and buy a new main battery please do not reconnect it to your existing Aux until, reversing the 2 steps I outlined before, at the very least until that Aux battery (which is probably shot) has been load tested in isolation, and proven to still be working well.

Generally, for those opting to run both batteries, replacement of either is reason to replace both.

 

[CreativeName]

Let's get past the academics and on to solution to get you out of the garage. The first step is to disconnect the Aux battery and bypass it. This is done by removing from the main battery's negative post the factory cable that does NOT connect to the body ground, leaving the latter connected, and then temporary insulating that loose cable end with electric tape.

Next, you will need to take the cover off the Power Distribution Center (PDC), that black box near the battery where your fuses are located. Identify Fuse 42, remove it, and keep it in a safe place.

Is it the one on the left that I’m removing?

 

[AndySpill]

Is it the one on the left that I’m removing?

I don't want to be a pill but I'm not going to answer that question only because at some point in the JLs production Stellantis seemed to switch the cables on the negative post of the main battery and I don't want give you wrong info.

Here's what I would like you to do instead. Follow the cable from the body ground to the main battery's negative post. Note it and leave it alone. Yank the other cable. This other cable you yank has, as its distal end, sight unseen, the negative post of the Aux battery, and disconnecting it at the main battery, and tapping up its end will take the Aux battery out of the electrical schematic of the vehicle.

 

[CreativeName]

I don't want to be a pill but I'm not going to answer that question only because at some point in the JLs production Stellantis seemed to switch the cables on the negative post of the main battery and I don't want give you wrong info.

Here's what I would like you to do instead. Follow the cable from the body ground to the main battery's negative post. Note it and leave it alone. Yank the other cable. This other cable you yank has, as its distal end, sight unseen, the negative post of the Aux battery, and disconnecting it at the main battery, and tapping up its end will take the Aux battery out of the electrical schematic of the vehicle.

Got the right one but sadly can’t turn the engine still. Will need to use the emergency neutral and push it out of the garage so I can get to the battery to change it (unless you think I could still get to it with a trickle charge)

Multimeter showing 3.5v now.

 

[THAW]

I don't want to be a pill but I'm not going to answer that question only because at some point in the JLs production Stellantis seemed to switch the cables on the negative post of the main battery and I don't want give you wrong info.

@CreativeName, the AUX (ESS) battery cable is always the smaller diameter one (so you were correct, the left).

Multimeter showing 3.5v now.

It appears your AUX (ESS) battery was actually propping up the CR[an]K (main) battery, but both are almost certainly damaged beyond repair.

 

[AndySpill]

Got the right one but sadly can’t turn the engine still. Will need to use the emergency neutral and push it out of the garage so I can get to the battery to change it (unless you think I could still get to it with a trickle charge)

Multimeter showing 3.5v now.

Can you try a jump, as opposed to trickle charger?

 

[gm920]

Got the right one but sadly can’t turn the engine still. Will need to use the emergency neutral and push it out of the garage so I can get to the battery to change it (unless you think I could still get to it with a trickle charge)

Multimeter showing 3.5v now.

Just rock your Jeep fore and aft and pop the transfer case into neutral. Much easier than dealing with the Park Override thingy. Have a chock or two handy if your driveway is not flat.

 

[CreativeName]

Had someone come over last night. Combining 2 boosters we were able to jump it. Will do the same again today to get it out of the garage so I can service the battery.

really appreciate everyone’s guidance and help with this mini fiasco. I know one thing for sure - I will buy some kind of battery maintenance thing next winter

@AndySpill - thanks for the elaborate explanations and support - your explanation, especially in regard to the early 2018 models was very much appreciated. Had no idea.

 

[hamiamham69]

I realize you are past the jump box at this point but something to note;,on the ones that I have owned one would need to press an over-ride button to try and jump a battery that has less then X number of volts. It does not sound like this was your issue per se but it’s good to know ..

 

[AndySpill]

@CreativeName

I am admittingly very ignorant with respect to your Canadian and Toronto provincial law as it regards vehicular inspection, and whether that inspection includes an examination of the your vehicle's diagnostics through the ODB II port by the driver's left knee.

On the rare chance that your battery replacement coincides with just such an inspection, and like in my locale involves access to the ODB II port, please consider trying to put that inspection off until you've driven about 100 miles (pardon 160 km) with the new battery.

Short anecdote: I swap my batteries every 3 years and last year did it just prior to my State's required annual inspection, which accesses this port. The inspection failed, which in my locale still involved expense on my part, because the lack of constant electrical current in the vehicle temporarily clears any diagnostic codes, and most inspection equipment is designed to fail the inspection if these codes can't be read, precisely because without this requirement people might "game the system," hiding problems with the vehicle revealed during inspection by disconnecting the battery(ies) just prior to bringing it into their mechanic for the procedure.

After such miles/km though, the computer will reset and the codes can be read.

 

[gm920]

@CreativeName

I am admittingly very ignorant with respect to your Canadian and Toronto provincial law as it regards vehicular inspection, and whether that inspection includes an examination of the your vehicle's diagnostics through the ODB II port by the driver's left knee.

On the rare chance that your battery replacement coincides with just such an inspection, and like in my locale involves access to the ODB II port, please consider trying to put that inspection off until you've driven about 100 miles (pardon 160 km) with the new battery.

Short anecdote: I swap my batteries every 3 years and last year did it just prior to my State's required annual inspection, which accesses this port. The inspection failed, which in my locale still involved expense on my part, because the lack of constant electrical current in the vehicle temporarily clears any diagnostic codes, and most inspection equipment is designed to fail the inspection if these codes can't be read, precisely because without this requirement people might "game the system," hiding problems with the vehicle revealed during inspection by disconnecting the battery(ies) just prior to bringing it into their mechanic for the procedure.

After such miles/km though, the computer will reset and the codes can be read.

They are called "Readiness Monitors" a quick and easy test is to turn ignition on, do not start, wait about 30 seconds. If CEL flashes during that time it means 1 or more monitors are not set. If CEL remains on steady you are good to go for testing.

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