ESS - Dealer Damaged Jeep - New Main Batt - AUX Delete

[UncleJimmy]

Hi, I'm hoping someone here can help me with ESS. It started with ESS light service warning. I took it to dealer and they damaged the paint down to bare metal. After they tried to cover it up initially they have now agreed for me to take it to a body shop of my choice and "then we'll talk".

Anyway, after reading up on some threads here, I replaced the main battery with an Odyssey H7 ($400 out the door). I deleted the AUX; taped up the AUX neg lead and rerouted the pos lead from the AUX to the Main batt pos terminal. Did not pull fuse. (Actually I tried pulling F42 and see if that cleared the ESS message and it did not). When I took the Jeep in to the dealer for the ESS light I also mentioned that on one occasion I hit a big bump and the ABS light went on and the service ABS message came on. It cleared itself after I turned the vehicle on and off and has not reappeared and I have been off road three times with no issues. They want to take the Jeep again and replace a wheel sensor. Not sure if they are just grasping for straws here and for obvious reasons I am hesitant to take the Jeep back to them but they are the only dealer within 100+ miles.

If anyone could shed some light on the subject I would sure be appreciative. We have a sick baby on O2 with out of town medical appointments and we need a dependable vehicle. I am not having any other problems in terms of drivability or starting, just the ESS light/message.

Thanks.

Update: I think I found the problem:

https://www.jlwranglerforums.com/fo...in-batt-aux-delete.109936/page-3#post-2288872

Sponsored

 

[roaniecowpony]

I hope your baby gets well soon.

Jeeps just being Jeeps. These electronic versions of a Jeep are just like a crazy girlfriend with a great bod.

 

[blnewt]

I'd go ahead and pull the fuse 42 just to get the aux completely bypassed (in case it's causing a drain on the main battery or any other issue). And just remember to push the ESS bypass button whenever you start it if you're not using a tazer or similar bypass tool.

Of course when visiting the dealer just put it back to stock w/ the fuse re-inserted so they won't question that.

 

[UncleJimmy]

I'd go ahead and pull the fuse 42 just to get the aux completely bypassed (in case it's causing a drain on the main battery or any other issue). And just remember to push the ESS bypass button whenever you start it if you're not using a tazer or similar bypass tool.

Of course when visiting the dealer just put it back to stock w/ the fuse re-inserted so they won't question that.

Thanks. The AUX is deleted . Out of the vehicle. So not sure I understand.

 

[blnewt]

Thanks. The AUX is deleted . Out of the vehicle. So not sure I understand.

sorry, I missed the part about you actually removing the aux battery. and echo @roaniecowpony sure hope your baby gets well soon.

 

[Fudster]

Hi, I'm hoping someone here can help me with ESS. It started with ESS light service warning. I took it to dealer and they damaged the paint down to bare metal. After they tried to cover it up initially they have now agreed for me to take it to a body shop of my choice and "then we'll talk".

Anyway, after reading up on some threads here, I replaced the main battery with an Odyssey H7 ($400 out the door). I deleted the AUX; taped up the AUX neg lead and rerouted the pos lead from the AUX to the Main batt pos terminal. Did not pull fuse.

Hi James:

Having read the entire thread I am surprised that the ESS light hasn't turned off given what you described, but I am pausing your thoughts at this point in your writing to make a point.

With the exception of some dual AGM battery (you, not people with a 48V battery JL, etc.) early model year 2018 JLs without TSB 18-092-19 flashed by the dealer (likely NOT you) here's what your vehicle does upon you attempting to cold crank it (finger on button, foot on brake):

The vehicle will energize a relay, provided fuse 42 is intact--which you reported this fuse was--i.e. you initially didn't remove the fuse--that will for an instant separate the batteries--normally connected in parallel at all times but at this point during the crank, and ESS events. It will then seek to test the ESS battery in isolation--which in your case should generate no power because you took the ESS battery out of the vehicle's electrical system when you disconnected and insulated the cable whose distal connection point is the ESS battery's negative terminal.

(Please make sure you disconnected the correct cable. It seems to have changed with the 2021 model year https://www.jlwranglerforums.com/forum/threads/ess-battery-cable-change.86624/.)

The JL should fail to crank....but, the next attempt to crank should (baring the 2018's I mentioned) automatically try doing so solely against the main battery. If successful, the vehicle should illuminate the "ESS off" light and "forever more" crank only against the main battery on the first try on your part, until, if ever, the next cold crank after an energized ESS battery is once again reintroduced and connected, or the vehicle is tricked into thinking an ESS battery is there.

What I just bolded is important for the following reason. Granted, you report not having reconnected an energized ESS battery, but by subsequently yanking Fuse 42, you have tricked your JL into thinking one is there. Allow me to explain.

The cold crank after the removal of Fuse 42 happens as follows. The vehicle attempts to energize the same relay I discussed above that separate the batteries. Without warning or idiot lights it will fail to do so because you yanked fuse 42. Now, all calls for power to either battery go to all batteries that are connected--which is your one main battery. In simpler terms your JL thinks your main battery is both your main and ESS battery.

And as usual it will test this ESS battery (or so it thinks) in isolation (which again is just your main battery). The test should be passed, the "ESS off" light turned off, and then the vehicle deenergizes the relay that separates the batteries (which it was never able to energize thanks to Fuse 42 being pulled) and both batteries are reconnected--or so your JL thinks, and it cranks using both botteries, which for you is just the main battery.

So--what I find confusing is why the ESS off light didn't shut off for you in the cold crank immediately following your pull of Fuse 42. Or did it and I just got confused by the folllowing:

(Actually I tried pulling F42 and see if that cleared the ESS message and it did not). When I took the Jeep in to the dealer for the ESS light I also mentioned that on one occasion I hit a big bump and the ABS light went on and the service ABS message came on. It cleared itself

James--what cleared itself...the ABS light or the ESS light or both/neither?

If your "ESS off" light turned off, this is exactly what should happen. If so please turn off ESS with a press of the ESS off button or aftermarket tech to do so as ESS events for you will not run off of the same battery responsible for cranking the vehicle. It's not the end of the world if this happens on occasion. Many vehicles run ESS systems with one battery, but the dual AGM battery JLs were not designed this way.

If your ESS off light (not button, light) remains illuminated would you please communicate that fact back here....

after I turned the vehicle on and off and has not reappeared and I have been off road three times with no issues. They want to take the Jeep again and replace a wheel sensor. Not sure if they are just grasping for straws here and for obvious reasons I am hesitant to take the Jeep back to them but they are the only dealer within 100+ miles.

If anyone could shed some light on the subject I would sure be appreciative. We have a sick baby on O2 with out of town medical appointments and we need a dependable vehicle. I am not having any other problems in terms of drivability or starting, just the ESS light/message.

Thanks.

 

[UncleJimmy]

Thanks Fudster for your reply. So let me see if I understand your points/question. So you are asking if the ESS light is off or ABS, correct? The answer is the ABS light warning was apparently a one time event that hasn't returned and cleared itself after I restarted the vehicle. The reason I mention it is that the dealer wants to take the Jeep back and replace a wheel sensor to see if that clears the ESS message. I am hesitant to take it back because of the damage done to the vehicle on the last visit, and the way they treated me initially (will see if they make it right). Also, they said it would take a while to get the part but they could find another one in a shorter period. I think what that means is they could take a perfectly good sensor and replace it with what I suspect is a remanufactured sensor. On the other hand, is it possible that is what's causing my issue and should I let them take the vehicle again??

So regarding the ESS, yes that light is on with the ESS unavailable message at start up and is what I'm trying to diagnose. Regarding the fuse and the way I disconnected the AUX I just want to clarify a few things. From what I've gathered so far reading the forum is that I know of at least three different ways to bypass or delete the AUX battery. See this discussion here (in hindsight I posted in the wrong thread):

https://www.jlwranglerforums.com/fo...ement-talk-jl-jt-🪫.100534/page-7#post-2278615

Some guys have done a method where they leave the AUX batt in the vehicle and isolate the neg lead at the Main batt terminal and pull F42. Others advocated for pulling the AUX out of the vehicle, isolating the neg lead from the AUX batt terminal and rerouting the pos lead from the AUX batt to the Main batt pos terminal, leaving both neg leads on the Main batt terminal and leaving the F42 intact. This is the method I did mainly because Genesis chimed in and said that is the method they use for their DBS. I did that three days ago and no change. So last night I bought a new Odyssey H7 even though the prior Main batt was only a few months old Walmart battery, I wasn't sure if there was a possibility that something drained it however the dealer said it tested good. Actually both prior Main and AUX were replaced a few months back and both tested good. But, as I said, I wanted to be sure so I pulled the AUX out, and replaced the Main with the Odyssey.

After this failed to clear the ESS last night, I decided to disconnect the neg cables from the Main batt and pull F42 to see if that changed anything. It did not so I reinstalled F42. Regarding the fuses, I should note that many were not seated fully and making sure all the relays and fuses were seated properly was one of the first things I did about a week ago. It did not make any difference.

I should note that this morning, the ESS message did not come on right away like it usually does but waited until the vehicle engine was warmed up, then the service ESS message came up and the ESS A! light came on. But I thought that was a slight improvement since it took a while to come on.

Regarding the TBS and the starting procedure, yes I did read threads on that and mine is a 2020 so from what I understand that update should already be there. During all these battery swaps etc. the vehicle always started normally on first try except for the ESS message/warning light.

I am not using any devices such as Tazer and the vehicle is bone stock. I bought it used three weeks ago and I don't know prior history except the batteries were replaced prior and have a manufacturer dat of 10/22. During the test drive the ESS worked normally, and came on about an hour into the drive home from the out of town dealer we bought it from. I know from the Carfax it sat on the non-Jeep dealer lot for 4-5 weeks so probably not driven much in that time and was one reason I decided to try replacing the Main/deleting the AUX.

I hope that clarifies things a little bit. From what I see now, I have a few alternatives. 1. Hope that someone here can give me some tips to try something else 2. take it back to the local dealer and let them replace the ABS which means I will probably need to reinstall the AUX again. 3. See if there any other dealers in the nearest metropolitan area that have a better reputation and try there. Logistically that would be difficult since they are 2 hours away. Also I should note I have about 6,000 mi/6 mos. left on the bumper to bumper warranty.

In some other threads I read (but did not fully understand) the possibility of blown fuses at one of the N terminals? Or possibly a short in a module? Also hoping that it just needs a few start/stop cycles and maybe it will clear itself. Just looking for other possibilities.

 

[Fudster]

Thanks Fudster for your reply. So let me see if I understand your points/question. So you are asking if the ESS light is off or ABS, correct? The answer is the ABS light warning was apparently a one time event that hasn't returned and cleared itself after I restarted the vehicle. The reason I mention it is that the dealer wants to take the Jeep back and replace a wheel sensor to see if that clears the ESS message.

Got it James. ABS light off--one shot deal, ESS off light remains illuminated...

I am hesitant to take it back because of the damage done to the vehicle on the last visit, and the way they treated me initially (will see if they make it right). Also, they said it would take a while to get the part but they could find another one in a shorter period. I think what that means is they could take a perfectly good sensor and replace it with what I suspect is a remanufactured sensor. On the other hand, is it possible that is what's causing my issue and should I let them take the vehicle again??

I don't blame you for feeling this way. I would too.

So regarding the ESS, yes that light is on with the ESS unavailable message at start up and is what I'm trying to diagnose. Regarding the fuse and the way I disconnected the AUX I just want to clarify a few things. From what I've gathered so far reading the forum is that I know of at least three different ways to bypass or delete the AUX battery. See this discussion here (in hindsight I posted in the wrong thread):

https://www.jlwranglerforums.com/forum/threads/-main-battery-replacement-talk-jl-jt-🪫.100534/page-7#post-2278615

Some guys have done a method where they leave the AUX batt in the vehicle and isolate the neg lead at the Main batt terminal and pull F42. Others advocated for pulling the AUX out of the vehicle, isolating the neg lead from the AUX batt terminal and rerouting the pos lead from the AUX batt to the Main batt pos terminal, leaving both neg leads on the Main batt terminal and leaving the F42 intact.

I'd argue that either technique you describe gets you to the same electrical outcome: the tricking of your dual AGM battery JL into thinking that calls for current that end up at the main battery are actually calls for current at the ESS battery, even though they are not.

It the first case, pulling Fuse 42 prevents the batteries from being isolated so that all calls for current from either battery always end up going to all batteries...or should I say all connected batteries: which in your case is just the main. Your vehicle is none the wiser. It thinks your main battery is both your ESS and your main battery.

In the second scenario a different wiring approach ends up at precisely the same outcome. Specifically all cables to factory batteries are now sitting on the main battery. In this case whether fuse 42 is pulled or not is moot. A hardwired connection to the main battery has been established by the owner via cable changes that the energization of the relay powered by Fuse 42 simply can't break.

This is the method I did mainly because Genesis chimed in and said that is the method they use for their DBS.

James: my take---please correct me if I am mistaken, is that Fuse 42 in your vehicle is intact, and that the cables the factory put on the main battery remain unchanged, while the cables the factory put on the ESS battery have been rerouted by you to their respective polarity terminals on the main battery....which by the way, if the case, seems to me certainly an acceptable way to go about eliminating your ESS battery.

I did that three days ago and no change. So last night I bought a new Odyssey H7 even though the prior Main batt was only a few months old Walmart battery, I wasn't sure if there was a possibility that something drained it however the dealer said it tested good.

I'd be curious as to the dealer's testing methodology of your Walmart battery. Did they load test it--which is the gold standard of testing that involves seeing whether the battery can delivery and accept charge (i.e. that which a battery does and needs to do) or did they simply put a volt meter to the battery, a test that can suggest a bad battery if voltage is low, but not conclude a good battery simply because voltage is high. To rephrase, a battery topped off with power and good voltage, but which can't deliver that current quickly and in full--something a volt meter cannot detect, is a bad battery.

Still more James, if the dealer simply put the battery tester's prongs to the main battery, it's time to find a new dealer. I say this because without first, at the very least, disconnecting the two batteries by isolating the cable that connects the two battery's negative cables, such a test would be one of composite voltage of both batteries that could mask defects in either one.
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Actually both prior Main and AUX were replaced a few months back and both tested good.

...with a wink in my eye, said testing was of the load variety against each individual battery...?

If not, your batteries weren't really, IMHO, tested.

But, as I said, I wanted to be sure so I pulled the AUX out, and replaced the Main with the Odyssey.

...fuse 42 still in place, cables that in the factory would normally lead to the ESS battery redirected to the Odyssey battery, correct?

After this failed to clear the ESS last night, I decided to disconnect the neg cables from the Main batt and pull F42 to see if that changed anything.

I wonder if the new Odyssey battery has issues. Of course it could be fine and something could be wrong with the vehicle. I will say this: from what you've described, keeping Fuse 42 intact and redirecting the factory cables that would normally go to the ESS battery, to the main battery, is electrically equivalent to pulling Fuse 42 and isolating and insulating the negative cable that normally connects the ESS and main batteries at their negative posts.

Rephrased it is curious to me that the ESS light has not shut off, but is not curious to me that if that ESS off light didn't shut off with Fuse 42 intact and the factory cables normally going to the ESS battery rerouted to the main battery, that it (the ESS off light) also would not shut off with Fuse 42 pulled and the negative factory cable coming from the ESS battery isolated and insulated, as these two approaches are essentially the same exact thing electrically. Both reroute all calls for current from the ESS battery to the main battery unknown to the JL.

Can you put the new Odyssey battery up to a charger for a while, perhaps run the JL on a somewhat longer higher trip to charge this new battery?

It did not so I reinstalled F42. Regarding the fuses, I should note that many were not seated fully and making sure all the relays and fuses were seated properly was one of the first things I did about a week ago. It did not make any difference.

Improperly installed fuses---a relatively common JL finding that can result in all sorts of difficult to diagnose gremlins.

I should note that this morning, the ESS message did not come on right away like it usually does but waited until the vehicle engine was warmed up, then the service ESS message came up and the ESS A! light came on. But I thought that was a slight improvement since it took a while to come on.

James: In light of this please see my thoughts above about giving that new Odyssey battery a good charge.

Regarding the TBS and the starting procedure, yes I did read threads on that and mine is a 2020 so from what I understand that update should already be there.

Absolutely. Assume all dual AGM battery JLs of model year 2019 or greater to have TSB 18-092-
19 functionality.

During all these battery swaps etc. the vehicle always started normally on first try except for the ESS message/warning light.

This finding comports perfectly with your description of the changes you clarified to me that you made. To rephrase, we expect the crank to fail on first try if the factory cables that lead to the ESS battery are not making a circuit with the vehicle AND fuse 42 is intact.

Your two changes never describe such a scenario IMHO. In the first you rerouted the ESS cables to the main completing a circuit to the cables that would normally go to the ESS battery--making the status of Fuse 42 moot. And in the second scenario you did electrically isolated the factory cables normally going to the ESS battery but you pulled fuse 42, preventing the relay that isolates the batteries from being energized, making all calls for electrical current to either battery to go to all available batteries all the time, and your available batteries, or should I say sole battery, was your main battery.

I am not using any devices such as Tazer and the vehicle is bone stock.

Noted James, and always best during such diagnostic periods. But when we get this problem behind us perhaps I can convince you to acquire tech that turns ESS off by effectively pushing the ESS button for you upon engine crank, or that you get into this habit yourself...your call. I think the Tazer Jl is great and does so much more than turn ESS off, but if turning ESS off is your only goal, the SmartStopStart device is cheaper and equally effective at this sole task.

I bought it used three weeks ago and I don't know prior history except the batteries were replaced prior and have a manufacturer dat of 10/22. During the test drive the ESS worked normally, and came on about an hour into the drive home from the out of town dealer we bought it from.

So..ESS is fine until, paradoxically, alternator charge is applied to the batteries during the drive home that should have kept it that way, or even allowed a temporarily disabled ESS system to come back online. I'd have to question the ability of the batteries you got the vehicle with to accept and deliver charge and/or the draw on them from the very aftermarket appliances you seem to not currently have.

I know from the Carfax it sat on the non-Jeep dealer lot for 4-5 weeks so probably not driven much in that time and was one reason I decided to try replacing the Main/deleting the AUX.

James...some perspective. If you have shore power near where you park, consider hooking your JL up to a trickle charge on a regular basis. Many of us (still running dual batteries) find that this is necessary for ESS to work reliably. Sad, but true. One battery or two, your connection point is to the main battery' terminals.

I hope that clarifies things a little bit. From what I see now, I have a few alternatives. 1. Hope that someone here can give me some tips to try something else

Try trickle charging.

2. take it back to the local dealer and let them replace the ABS which means I will probably need to reinstall the AUX again.

3. See if there any other dealers in the nearest metropolitan area that have a better reputation and try there. Logistically that would be difficult since they are 2 hours away. Also I should note I have about 6,000 mi/6 mos. left on the bumper to bumper warranty.

In some other threads I read (but did not fully understand) the possibility of blown fuses at one of the N terminals? Or possibly a short in a module? Also hoping that it just needs a few start/stop cycles and maybe it will clear itself. Just looking for other possibilities.

Let me talk to the latter. Those high amp fuses on the driver's side of the Power Distribution Center (PDC) are such that if blown, the entire series of fuses need to be replaced, but by no means the entire PDC. I believe a blown N3 will prevent the alternator from charging the battery.

Best wishes for both your "babies" getting well.

 

[UncleJimmy]

Fudster, I appreciate the detailed response and well wishes for my "babies".

I agree based on what I have read on other threads that the prior batteries might not have been load tested correctly or that the dealer may or may not have isolated the batteries properly for the test, hence my decision to shell out for the best battery I could find and pull the AUX out so I could rule out bad batteries as the main issue, which seemed to be the general first rule of thumb on the forum in diagnosing these common issues. I have a trickle charger and I will certainly try that overnight tonight and see if that solves the issue. Just for further background information, the new Odyssey tested 12.94v DC on my volt meter prior to installation.

The Tazer looks like a good option and I will look into that in the future once this is all sorted out. I don't like how the electronic disconnect constantly engages/disengages off-road over 18 mph.

Note: I see anywhere from low to mid 13v to 14.4v on the display while driving so I assume that means the alternator is charging properly?

Yes, the F42 is intact and all factory cables are intact on the Main with the pos on the AUX rerouted to the pos main and the neg on the AUX taped up and left in the OEM AUX battery box. The negs on the Main are intact as well. Just for clarification and for anyone else viewing this thread, this is the method I used for the AUX delete:



Here are some pics of the delete:

Let me know if I missed any of your points. Thanks again.

 

[UncleJimmy]

Just realized at the end of that video he says "2021 and newer you will need to attache the neg ground from the AUX back to neg on main or you will get an error". Mines a 2020 so I didn't do that, I just taped it off as he did in the video. I wonder if I should try doing that....

 

[Fudster]

Just realized at the end of that video he says "2021 and newer you will need to attache the neg ground from the AUX back to neg on main or you will get an error". Mines a 2020 so I didn't do that, I just taped it off as he did in the video. I wonder if I should try doing that....

Hi again James:

I am caught up with your thoughts here since the last I spoke, have watched the Youtube video you linked and have a couple of thoughts.

Perhaps the poster of the video felt the need to re-connect the negative cable whose distal end from the factory was the negative terminal of the ESS battery for the reasons I cited in my prior link to this cabling change. https://www.jlwranglerforums.com/forum/threads/ess-battery-cable-change.86624/

I would think the connection of this cable would do absolutely no harm nor no good. In fact if I've got things correct in my head it would seem that both ends of the cable would get attached to the negative terminal of the main battery, which would positively (no pun intended) do no harm nor no good.

Perhaps the Youtube poster meant that the connection between the main battery's negative post and the body ground, the latter located on the front passenger's quarter panel under the hood needed to be attached, which if so, I completely agree with, it certainly does; it's critical.

The idea that you experienced a period where the ESS off was not illuminated shortly after crank and also after the installation of the Odyssey battery leads me to want to investigate if that battery is getting the charge it needs. Towards that end I feel the trickle charging provides the battery with an external source of charging that hopefully can top it off to see if the ESS off light shuts off at the next crank or not. If it doesn't I would find me taking a couple of directions from load testing the new battery to making sure that fuse N3 isn't blown, to electrical shorts, etc.

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

All this said, I want to climb down another rabbit hole with you. Given our talk, I'm now upping the number of ways that one bypasses an ESS battery to 4, from 3. There's the original technique from years ago of1) jumpering the high amp fuses N1 and N2 in the PDC, along with disconnecting the negative cable from the ESS battery, then there's 2) pulling the F42 fuse with the same cable disconnect, then there's the 3) rerouting of cables originally attached to the ESS battery to the main battery--where the pulling of Fuse 42 or not is moot (herby dubbed the Genesis Offroad technique) ...and finally, there's the "step child technique" not to be confused with a bunch of Youtube Jeep enthusiasts (Lite Brite) with a JL of the same name.

The step child technique is for all dual AGM battery JLs except the earliest 2018's not flashed with the aforementioned TSB. Here goes:

Disconnect the cable that begins at the ESS negative post and insulate it. Close the hood, or at least stop. No Fuse 42 pulling, not cabling rerouting.

Step two: attempt to crank your JL. Expect it to fail. No ESS battery was found, no bypass was installed.

Now....try cranking again. The JL should seek out the main battery solely to crank the engine. If successful, the vehicle will turn on the ESS off light, and forever more crank on the first try from only the main battery. Only the presence of an energized ESS battery, or the cabling to trick the JL into thinking there's one present will, on the next crank thereafter, turn that "ESS off" light off.

Now comes the philosophy...Is this such a bad thing? If a Jl owner hates idiot lights in the dash well then they should use one of the first 3 techniques to fool the JL into thinking it has an ESS battery. But I don't see this ESS off light coming and staying on as a downside...I see it as a feature.

You don't want to engage ESS with one battery and the vehicle has turned ESS off for you, avoiding the need to remember to to do at each cold crank or by purchasing tech to do it for you.

Food for thought. But if you want that ESS off light to shut off, you'll need to use one of the three ways to trick the vehicle into thinking it has an energized ESS battery.

I hope this makes sense. If not, do ask me to clarify.

 

[Fudster]

Oh James...one more thing......from your pictures it would appear that you removed the ESS battery from above by disassembling the PDC, as opposed to coming at the battery from the passenger's front fender liner.

I take no issue with that, but make sure that--if I've got your method right---that you carefully put all the PDC components back together without bending any pins in the process.

 

[UncleJimmy]

Hi Fudster, Again I appreciate all the help so far!

My understanding in Ali Mansour's (Driving Line) video is that he isolated the neg battery lead that was previously attached to the AUX. I read in the comments below the video where he explained that's what he did. And he goes on to clarify again he was told (probably by Genesis) that for 2021+ that neg AUX cable should be routed to the neg Main batt terminal. At least that's how I understood it. I'm wondering if my 2020 is the same as the later 2021 and could be why I'm getting the error? I could be wrong, but the way I understood it is that the ground was not touched either way.

Regarding the "step child technique" lol! again, if I understood you correctly, how is that any different than what I did with the "Genesis" method, in that in both instances F42 remains intact, the neg lead that was formerly on the AUX is isolated, the only difference being the pos is either still on the AUX or on rerouted to the pos of the Main? Sorry if I am not understanding you completely.

Regarding looking at the error message as a feature: I agree with you 100% provided there are no underlying faults somewhere else that would make the vehicle unreliable or create expensive repairs down the line when my bumper to bumper warranty is expired in 6 mos.

My current plan is to: 1. try trickle charging the new Odyssey tonight 2. try connecting the now isolated neg AUX lead to the Main batt neg terminal (I think you said that should not do any harm?) 3. not do anything and just leave it vs having the dealer poking around my Jeep endlessly, potentially creating more problems and hope I never have any more issues other than a warning light on the dash. What do you think?

 

[Fudster]

Hi Fudster, Again I appreciate all the help so far!

My understanding in Ali Mansour's (Driving Line) video is that he isolated the neg battery lead that was previously attached to the AUX. I read in the comments below the video where he explained that's what he did. And he goes on to clarify again he was told (probably by Genesis) that for 2021+ that neg AUX cable should be routed to the neg Main batt terminal. At least that's how I understood it. I'm wondering if my 2020 is the same as the later 2021 and could be why I'm getting the error? I could be wrong, but the way I understood it is that the ground was not touched either way.

Regarding the "step child technique" lol! again, if I understood you correctly, how is that any different than what I did with the "Genesis" method, in that in both instances F42 remains intact, the neg lead that was formerly on the AUX is isolated, the only difference being the pos is either still on the AUX or on rerouted to the pos of the Main? Sorry if I am not understanding you completely.

Rereading this thread I'd like to add to keep us informed of the voltage reading on your dash. We'd like to see that go down as your drive. High values are often significant of an alternator working double duty to ram power into a battery.

You ask immediately above how the step child technique differs from yours. Let's step back for a second. At some point I thought the Genesis approach involved rerouting the cables that go to the ESS battery, positive and negative, to the main. I didn't realize the Genesis approach left the negative that emanates from the ESS battery "isolated and insulated," along with fuse F42 intact.

Given that, what you did and the step child technique appear to be one and the same.
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Regarding looking at the error message as a feature: I agree with you 100% provided there are no underlying faults somewhere else that would make the vehicle unreliable or create expensive repairs down the line when my bumper to bumper warranty is expired in 6 mos.

Complete agreement. The only reason that ESS off light should be illuminated is because of a deliberate rewiring that caused the crank to initially fail, because the vehicle couldn't find an energized ESS battery (or what it thought, via cable rewiring, was an energized ESS battery) followed by a successful crank against the main battery. A completely agree that we don't want that light coming on for other reasons.

To rephrase, so we are on the same page, the step child technique (i.e. removing the negative from the ESS to the main negative only) is only properly done after we've confirmed that the ESS off light does NOT come on prior to effecting this cabling change.

My current plan is to: 1. try trickle charging the new Odyssey tonight 2. try connecting the now isolated neg AUX lead to the Main batt neg terminal (I think you said that should not do any harm?) 3. not do anything and just leave it vs having the dealer poking around my Jeep endlessly, potentially creating more problems and hope I never have any more issues other than a warning light on the dash. What do you think?

Sounds good. Let us know after this if the next crank turns the "ESS off" light off.

 

[The Last Cowboy]

Oh James...one more thing......from your pictures it would appear that you removed the ESS battery from above by disassembling the PDC, as opposed to coming at the battery from the passenger's front fender liner.

I take no issue with that, but make sure that--if I've got your method right---that you carefully put all the PDC components back together without bending any pins in the process.

When I replaced my aux battery from the top (not that complicated by the way), I found afterward that my climate control panel didn't work and that there was an ESS error message. The ESS control switch is on the climate control panel. I disassembled the PDC and found that a pin was bent on reassembly. I was able to strighten it out with some needle nose pliers and all was well after it was reassembled.

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