Sponsored

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

OP
OP
UncleJimmy

UncleJimmy

Well-Known Member
First Name
James
Joined
Mar 22, 2019
Threads
3
Messages
204
Reaction score
132
Location
AZ
Vehicle(s)
2020 JLUR; 2016 Toyota Tundra
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 straighten it out with some needle nose pliers and all was well after it was reassembled.
Thanks for the tip Maybe it's worth it to disassemble the PDC and check for bent pins.

Rereading this thread I'd like to add to keep us informed of the voltage reading on your dash.
Last night I drove on the HWY at 65 mph for about a half hour, then drove back after a stop. The voltage was pretty constant at 14.2. The outside temp was in the low 40s F. This morning after trickle charging the battery overnight, the voltage was 13.5 at 25 F. There was no error message for about five minutes until the vehicle warmed up, then the ESS message/light came on.
Sponsored

 

Fudster

Banned
Banned
Banned
First Name
Elliot
Joined
Mar 9, 2022
Threads
29
Messages
657
Reaction score
673
Location
Athens, GA
Vehicle(s)
2019 Sahara
Thanks for the tip Maybe it's worth it to disassemble the PDC and check for bent pins.



Last night I drove on the HWY at 65 mph for about a half hour, then drove back after a stop. The voltage was pretty constant at 14.2. The outside temp was in the low 40s F. This morning after trickle charging the battery overnight, the voltage was 13.5 at 25 F. There was no error message for about five minutes until the vehicle warmed up, then the ESS message/light came on.
Hi James:

Please clarify for me so that we both remain on the same "page."

From the moment you cranked this morning what were the status of two independent messages in the dash...the first being the "idiot light" that reads "ESS off" and the second being the advisory message in the dash that the "ESS system is not ready."

Thanks.
 
Last edited:
OP
OP
UncleJimmy

UncleJimmy

Well-Known Member
First Name
James
Joined
Mar 22, 2019
Threads
3
Messages
204
Reaction score
132
Location
AZ
Vehicle(s)
2020 JLUR; 2016 Toyota Tundra
Hi James:

Please clarify for me so that we both remain on the same "page."

From the moment you cranked this morning what were the status of two independent messages in the dash...the first being the "idiot light" that reads "ESS off" and the second being the advisory message in the dash that the "ESS system is not ready."

Thanks.
Hi Elliot,

At start this morning no message.
Battery charge at 13.4v-13.5v at 25F.
Scrolled to stop/start screen. It said, Stop/Start unavailable due to low engine temp.
After 5 mins and engine warmed up the message flashed, stop/start unavailable - service system (or something to that effect)
ESS warning light "A!" lit up on dash and remained.

Hope that answers your questions. Thanks.
 

Fudster

Banned
Banned
Banned
First Name
Elliot
Joined
Mar 9, 2022
Threads
29
Messages
657
Reaction score
673
Location
Athens, GA
Vehicle(s)
2019 Sahara
Hi Elliot,

At start this morning no message.
Battery charge at 13.4v-13.5v at 25F.
Scrolled to stop/start screen. It said, Stop/Start unavailable due to low engine temp.
After 5 mins and engine warmed up the message flashed, stop/start unavailable - service system (or something to that effect)
ESS warning light "A!" lit up on dash and remained.

Hope that answers your questions. Thanks.
Completely.

I admit to being a bit at the end of my diagnostic rope. What I mean by that is short of being on scene, my ability to further diagnose, let alone remedy your issues is limited.

Others here may have advise where my shortcomings lie.

That said, I do James want to leave you with some thoughts as it regards further areas of examination so as to determine cause.

I find it noteworthy that your ability to run ESS, at least as determined by your vehicle, is one that shuts down with driving, as opposed to being initially unavailable at crank--due to things like a cold engine or less than fully charged battery--and then with some mileage becomes available.

Sometimes, diagnosing a problem isn't about attacking what is most likely the cause first, but ruling out what isn't the cause first if that proves a cheaper and easier route. That sentence deserves clarification.

To rephrase, were it me--and the fact that I already own a battery load tester plays strongly into this--I'd load test the new battery. I suspect it would pass with flying colors, but in so doing find more me forced to examine various components under the hood, regrettably with the very so called expert techs that did a number to your paint, that both extract and supply energy to that battery otherwise ruled out as a culprit in your issues.

Perhaps, before the dealer visit we can confirm that all aspects of the Power Distribution Center (PDC) are seated properly, and that none of the high amp fuses on the driver's side of the PDC are blown. To reiterate, if any of those fuses are blown it will require the entire fuse array to be replaced (and I believe there are different part numbers for that array depending on things like if you have the towing package with more powerful alternator/batteries) but by no means do not let anyone sell you on an entire PDC swap simply because a high amp fuse might have blown.




If new symptoms arise please do come here as I and others may have more informed responses to help you with.

I wish you the best of luck getting this resolved.

P.S. The very fact that the ESS off light was not illuminated on cold crank suggests to me that your vehicle thinks it "sees" an energized ESS battery. Now of course, you don't have one (an ESS battery,) but what you do have is a situation where you have rerouted the cables that would normally draw power off of the ESS battery to the main battery, leaving your vehicle none the wiser.
 
Last edited:
OP
OP
UncleJimmy

UncleJimmy

Well-Known Member
First Name
James
Joined
Mar 22, 2019
Threads
3
Messages
204
Reaction score
132
Location
AZ
Vehicle(s)
2020 JLUR; 2016 Toyota Tundra
I admit to being a bit at the end of my diagnostic rope. What I mean by that is short of being on scene, my ability to further diagnose, let alone remedy your issues is limited.
Thanks Elliot. I appreciate the help.

I find it noteworthy that your ability to run ESS, at least as determined by your vehicle, is one that shuts down with driving, as opposed to being initially unavailable at crank--due to things like a cold engine or less than fully charged battery--and then with some mileage becomes available.

Sometimes, diagnosing a problem isn't about attacking what is most likely the cause first, but ruling out what isn't the cause first if that proves a cheaper and easier route. That sentence deserves clarification.
I agree with both points.

To rephrase, were it me--and the fact that I already own a battery load tester plays strongly into this--I'd load test the new battery.
Do you think the guys at AutoZone can do a proper battery test? I've read contrary opinions on the forum.

Perhaps, before the dealer visit we can confirm that all aspects of the Power Distribution Center (PDC) are seated properly, and that none of the high amp fuses on the driver's side of the PDC are blown.
I will check that.

and that none of the high amp fuses on the driver's side of the PDC are blown.
Is that something I can do?

if you have the towing package with more powerful alternator/batteries) but by no means do not let anyone sell you on an entire PDC swap simply because a high amp fuse might have blown.
I do have the tow package. Thanks for the advice on PDC swap.

I wish you the best of luck getting this resolved.
Thanks again Elliot.
 

Sponsored

OP
OP
UncleJimmy

UncleJimmy

Well-Known Member
First Name
James
Joined
Mar 22, 2019
Threads
3
Messages
204
Reaction score
132
Location
AZ
Vehicle(s)
2020 JLUR; 2016 Toyota Tundra
Watching the video now. I see he's going to show the fuse replacement.
 

Fudster

Banned
Banned
Banned
First Name
Elliot
Joined
Mar 9, 2022
Threads
29
Messages
657
Reaction score
673
Location
Athens, GA
Vehicle(s)
2019 Sahara
I do believe that your auto store is more likely than not to be able to correctly effect a load test. :)
 
OP
OP
UncleJimmy

UncleJimmy

Well-Known Member
First Name
James
Joined
Mar 22, 2019
Threads
3
Messages
204
Reaction score
132
Location
AZ
Vehicle(s)
2020 JLUR; 2016 Toyota Tundra
Thanks! That's a beautiful Jeep BTW. Love the Sarge Green :like:
 

Sponsored

OP
OP
UncleJimmy

UncleJimmy

Well-Known Member
First Name
James
Joined
Mar 22, 2019
Threads
3
Messages
204
Reaction score
132
Location
AZ
Vehicle(s)
2020 JLUR; 2016 Toyota Tundra
Aren't I supposed to have a heavy duty cooling fan with the tow package/HD electrical group?

Is there supposed to be cable on the N4 fuse array? I am supposed to have Auxiliary switches I thought. The reason I ask is the terminal looks scratched as if there was a nut on there before.

I tested the fuse array N* terminals by checking each one with a volt meter. All showed current so I think that is supposed to mean the fuses are good, at least according to this thread:

https://www.jlwranglerforums.com/fo...ess-n3-fuse-warning.66247/page-2#post-1973951

fuse array.jpg


cooling fan.jpg


tow package.jpg
 
OP
OP
UncleJimmy

UncleJimmy

Well-Known Member
First Name
James
Joined
Mar 22, 2019
Threads
3
Messages
204
Reaction score
132
Location
AZ
Vehicle(s)
2020 JLUR; 2016 Toyota Tundra
I also verified the alternator was putting out current at 12.85v. It measured the close what the vehicle dash said. I followed the methods in the thread I posted above.

Going by a process of elimination, I think I have ruled out the batteries (unless I need to attach the neg AUX lead to the neg main batt instead of isolate it). I think I have ruled out the alternator and the N fuses in the fuse array. So would that leave the PCR module, correct? Does pulling F42 fuse bypass the PCR? I may try pulling that fuse again....
 

Buddy Lee

Well-Known Member
First Name
Victor
Joined
Dec 3, 2020
Threads
17
Messages
217
Reaction score
516
Location
San Martin, California
Vehicle(s)
2021 JL Rubicon Unlimited
N1 on fuse array is powered by the Aux battery through the PCR. N2 feeds the main battery positive. N3 is also connected to the PCR / Aux battery and is the power source for N1. N4 is empty, and used for a spare. N5 powers your fan 60 amp normal- 100amp tow package. The last 2 power your electric steering pump and the alternator/ starter. Fuse 42 powers the PCR which monitors current between the batteries and pulling it will remove it from the system. I did not like the ESS system so I totally removed it, including the Aux battery, PCR and all the cables. My jeep now has one battery and it works great with no lights. There are a few things to do if you decide to do that but it’s worth it in my opinion. Just be aware that you could have issues at the dealership for warranty work. I chose to have a better jeep and take my chances. I had an ESS light on as well for months and chose to remove it instead of going to the dealership and having the same issues you are.
 
OP
OP
UncleJimmy

UncleJimmy

Well-Known Member
First Name
James
Joined
Mar 22, 2019
Threads
3
Messages
204
Reaction score
132
Location
AZ
Vehicle(s)
2020 JLUR; 2016 Toyota Tundra
N1 on fuse array is powered by the Aux battery through the PCR. N2 feeds the main battery positive. N3 is also connected to the PCR / Aux battery and is the power source for N1. N4 is empty, and used for a spare. N5 powers your fan 60 amp normal- 100amp tow package. The last 2 power your electric steering pump and the alternator/ starter. Fuse 42 powers the PCR which monitors current between the batteries and pulling it will remove it from the system. I did not like the ESS system so I totally removed it, including the Aux battery, PCR and all the cables. My jeep now has one battery and it works great with no lights. There are a few things to do if you decide to do that but it’s worth it in my opinion. Just be aware that you could have issues at the dealership for warranty work. I chose to have a better jeep and take my chances. I had an ESS light on as well for months and chose to remove it instead of going to the dealership and having the same issues you are.
Thanks for that info. I have pulled the AUX as well I am just trying to diagnose the ESS warning light to make sure I don't have more serious issues now or in the future. I already found I don't have the heavy duty fan even though I think I am supposed to. If I can get all that resolved then I may do what you did for the added reliability and simplicity.
 

Fudster

Banned
Banned
Banned
First Name
Elliot
Joined
Mar 9, 2022
Threads
29
Messages
657
Reaction score
673
Location
Athens, GA
Vehicle(s)
2019 Sahara
I also verified the alternator was putting out current at 12.85v. It measured the close what the vehicle dash said. I followed the methods in the thread I posted above.

Going by a process of elimination, I think I have ruled out the batteries (unless I need to attach the neg AUX lead to the neg main batt instead of isolate it). I think I have ruled out the alternator and the N fuses in the fuse array. So would that leave the PCR module, correct? Does pulling F42 fuse bypass the PCR? I may try pulling that fuse again....
Hi again James:

Pulling Fuse 42 prevents the (PCR) Power Control Relay from being energized. If you'd prefer your wording, it bypasses the relay from ever being energized.

If I simply stopped my explanation there I feel that it would be a disservice.

As you may know a relay is an electronic switch. Small amounts of current are used to control the state of the switch, on (closed) or off (open).

That switch in turns allows current to flow, or not flow on a different circuit from the circuit which controls the switch--that different circuit in this case is one that connects the two factory batteries (if connected) in parallel when the relay is not energized (i.e. 99% of the time.)

(....100% of the time if you yank Fuse 42)


Your PCR is a normally closed relay. This means that when not energized--(and an attempt for the vehicle to energize that PCR by the way ONLY happens during ESS events and for an instant during ***normal cold cranks***) that relay switch is closed and the two batteries (or whatever the factory cables lead to) are connected in parallel.

If you want to pull that fuse that's fine with me. As a result of doing so, to reiterate, any calls for current from only the ESS battery will go instead to all available batteries (because if you can't energize the relay you can't separate the batteries).

And of course, for you, all available batteries is only your main battery.

James: I want to describe for you 3 things on your vehicle that an electrical engineer would draw the same on an electrical schematic and another electrical engineer reading that schematic would interpret as electrically identical:

1) Jumpering N1 to N2, 2)pulling fuse 42, and/or 3)taking the cables normally connected to the ESS battery and moving them to the main battery.

All three reroute calls for electrical current from, and charging to the main battery only.

You have already, I'm to understand, put the cables originally on the ESS battery's terminals (choice 3 above) on the main battery, yes? If so, and that didn't help you, neither will options 1 or 2 above as they are electrically identical outcomes. The electrons in the wires all flow the exact same way in any of these 3 scenarios without so much of a care as to which of the 3 (heck all 3 at the same time if you want) you pick.

unless I need to attach the neg AUX lead to the neg main batt instead of isolate it
If you yank Fuse 42, putting the negative from the Aux battery on to the main battery is neither wrong nor required. It's superflous: in excess. Pulling Fuse 42 guarantees that all calls for current from the ESS battery alone end up on the main battery. If you wish to drive the point home by attaching this cable on to the main battery, feel free, but it is not required and it will not "help" or change things if Fuse 42 is yanked.

If you don't attach this cable AND you don't pull Fuse 42, given that you you don't have an early model 2018 dual AGM battery JL, your initial cold crank attempt should fail, as the pre cold crank ESS battery test will be unable to find an energized ESS battery given this dangling cable. But subsequent attempts at cranking should go only against the main battery, and if successful illuminate the ESS off light forever more, and crank on the first try therafter against only the main battery, until, if ever, an energized ESS battery is reintroduced, or you've tricked your JL into thinking one is there with cabling or fuse changes or jumpers (N1 o N2). This cranking only against the main battery is my definition of what is NOT a normal cold crank as asterisked above.

I'm sorry this is all so confusing. This JL ESS system's connections are not for the "faint of heart."
Sponsored

 
Last edited:
 



Top