2020 Gladiator Electrical Issues

[KR36]

So I bought a certified 2020 Gladiator this past February. Haven’t really had any issues up until a few days ago. Randomly the truck wouldn’t start and required a jump. Drove it to work, turned it off and cycled it back on to ensure it was good and things were fine. Fast forward 8+ hours and it required another jump. I ended I driving it home and had it towed to my local dealership.

I got a call from the dealer the next morning telling me if it was a battery issue it wouldn’t be covered under my certified warranty or my Mopar warranty. This left me pretty disappointed since I had just purchased the truck 9 months and it’s less then 2.5 years ago. The dealership wanted me to pay a $175 diagnostic fee if it wasn’t covered under warranty…. We ended up deciding to have the truck sent through their quick service area and have them do an oil change and test on the batteries. Turns out both batteries were dead….. 2.5 years after manufacture and 50k miles. My mind was blown!

So I decided to authorize the dealer to replace both batteries (even though the service advisor and I agreed it was weird how soon the batteries failed) $720 later (oil changed included) I picked up my truck and things were fine. Fast forward 12 hours later…. I was leaving work and hit the remote start and all was good. I unlocked the truck and went to step in and the engine kicked off. I tried to restart and nothing….. No crank, just a bunch of dash lights…. I plugged in my scanner and it was throwing all sorts of weird codes…. I ended up having to have it towed back to the dealer.

I understand batteries are a maintenance thing, but clearly the batteries weren’t the issue. Has anyone had any of the following error codes or issues with their 2020 or 2021 Gladiator? If so, we’re you able to fix the issue and at who's cost? I opted out of a 2011 GC for a “New” Jeep because I was tired of the mechanic visits…. Super frustrated right now. Any help or guidance would be greatly appreciated!

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[Tommyd]

I would not have paid for batteries if I was still under warranty. That’s messed up. That’s a lot of codes.

 

[ZoMojave]

Turns out both batteries were dead….. 2.5 years after manufacture and 50k miles. My mind was blown!

I would not have paid for batteries if I was still under warranty. That’s messed up. That’s a lot of codes.

Looks as if the 3/36 factory warranty has expired.

 

[Tommyd]

Looks as if the 3/36 factory warranty has expired.

Shoot didn’t see he was at 50k

 

[Kevin_D]

This sounds like what happens when the High Current Fuse (N3) is blown, and the Aux. Battery doesn't charge properly.

Kevin

 

[KR36]

Hi Kevin,
Thanks for the reply! Have you had a similar experience? Do you know what would cause the Aux battery to not charge right even after installing a new battery? Do you think the new batteries have too much power and over exerted an already failing N3 Fuse? Or do you think there is a glitch in one of the computer modules that the new batteries overpowered? Would love to hear your thoughts on this.

 

[ZoMojave]

Hi Kevin,
Thanks for the reply! Have you had a similar experience? Do you know what would cause the Aux battery to not charge right even after installing a new battery? Do you think the new batteries have too much power and over exerted an already failing N3 Fuse? Or do you think there is a glitch in one of the computer modules that the new batteries overpowered? Would love to hear your thoughts on this.

There is a past thread on this subject that may be of help to you. Search "Fuseable Link".

 

[Lost1wing]

Looks like a power issue. I would check the battery installation. Check the ground wire at the fender. An over zealous tech may have over tightened it or perhaps it just loose. Checking the fuses is a good idea. I usually suspect what the last guy touched.

 

[Hootbro]

Just about all those codes are cascading codes from a power loss event. Since your dealership replaced the batteries on your dime, they need to honor the CPO warranty and dive into it.

I will be realistic and say upfront that you are probably going to deal with some incompetence when it comes to many dealership techs deep diving and find a root cause to correct. There may be some hunt and peck from them with a few parts shotgun at it before they get to the real problem.

 

[Kevin_D]

There is a past thread on this subject that may be of help to you. Search "Fuseable Link".

There are a lot of previous threads regarding this issue.

Look at this thread over on the Wrangler Forums:

https://www.jlwranglerforums.com/forum/threads/3-6l-ess-battery-diagram.14401/

You'll get a better understanding of the whole Main/Auxiliary Battery relationship.
Fuse N3 can be blown by improperly jump-starting the JT/JL.

It's easy enough to test N3, if you have a voltmeter. Take the cover off the fusebox, and measure between N2 & N3...

If you measure a voltage between these two, then the fuse is open, or the PCR (Power Control Relay) is bad.

Kevin

 

[ShadowsPapa]

Fuse N3 can be blown by improperly jump-starting the JT/JL.

How do you improperly jump start a JT?
All ya gotta do is connect to the tab on the crank battery positive and the top of the IBS on the crank battery, or better yet - the ground stud on the fender where the crank battery and aux battery ground to the chassis. Wait a few seconds (people seem to want to connect and start cranking as fast as that last clamp is in place)
The Grand Cherokee even has jump start studs there because the batteries are so hard to connect to. And those are the same points electrically as I mentioned on the JT

Just about all those codes are cascading codes from a power loss event.

Yup - he can pretty much ignore all that stuff. Reset and start over.

Do you know what would cause the Aux battery to not charge right even after installing a new battery? Do you think the new batteries have too much power and over exerted an already failing N3 Fuse? Or do you think there is a glitch in one of the computer modules that the new batteries overpowered?

Overpowered? No, no way.
Dealerships need to charge the aux battery and the crank battery independently and reset the IBS. If the aux battery is deemed dead, then they should always check the N3 fuse.
A battery can't have too much power. Not possible. No, a new battery won't blow that huge fuse! Only a fool working with a live system, or hitting the wrong wires/leads together while doing something would normally blow that fuse. It's a huge fuse - I believe 125 or 150 amps.
Batteries can't overpower anything. People do, but not batteries.
Fuses are between a battery and a load. A fuse blows if the load is too great or there's a "short", etc.

When a Jeep sits, engine off, owner inside having coffee, the two batteries are connected in parallel. Unless there's a problem like a bad PCR, the voltage between the two levels out - the battery with the highest voltages "charges" the battery with the lower voltage until there's equilibrium. If the aux battery is bad and low enough, that drains the crank battery to the point of not starting the engine.
So if the aux battery is sitting at 30% charge and 12 volts and the crank battery is at 100% charge and 12.7 volts, after sitting for a while the crank battery "charges" the aux battery and they both end up somewhere between 12.0 and 12.7 volts - unless the PCR is bad. If the aux battery is bad, it drains the crank battery.
N3 is for charging the aux battery and is between the high amperage fuse bus bar and the aux battery. That fuse can be blown by improper handling of the cables while working on the truck or if the aux battery shorts internally. It's not common for them to blow otherwise.

 

[Kevin_D]

How do you improperly jump start a JT?
<snip>
That fuse can be blown by improper handling of the cables while working on the truck or if the aux battery shorts internally.

That may have been what I was thinking, but I thought I’ve read that the N3 fuse has been blown while jump starting, although it is difficult to imagine how.

Kevin

 

[ShadowsPapa]

That may have been what I was thinking, but I thought I’ve read that the N3 fuse has been blown while jump starting, although it is difficult to imagine how.

Kevin

One reason why I only ever pull the negative clamp off the crank battery and never the positive is that if you pull the positive and it somehow touches ground, it can blow that fuse.
Unless you pull the clamp off the crank battery negative AND separate the aux ground from the the other cable at the IBS as well, then pulling the positive cable off is risky.
If it touches ground, because you did not take the set of negative cables apart, you blow that fuse. So if you want to pull the positive off the crank battery, be really sure to take apart all cables that go to the negative terminal. If you leave things connected, ground is still ground.
With credit going to friend Jerry for his cool "spark" and lightening bolt graphics on this pic - this is how it happens -

You THNINK or believe you have things under control because see - you pulled the ground cable off the ,main battery so life is good. BUT - the aux is still grounded to the chassis because it's tied to the ground cable going to the fender/body.
So you pull both cables off crank battery, and let the positive battery clamp rest somewhere and it slides to a metal part - bang, you just blew N3 and cost yourself over 70 bucks.
So that's one reason I leave that positive cable safely on the main battery.

But for jump starting it's like it has been for forever..........
Try to make sure things are off as much as you can.........
Connect positive jumper cable to dead battery positive (pull cover back, clip to the cable on crank battery post)
Connect other end of jumper + to the donor vehicle's battery + terminal
Connect negative of jumper cable to the negative terminal of the donor vehicle battery
Connect other end of jumper negative to a good ground on the dead vehicle - not the battery terminal.
I suspect the book may agree, can't see why it would change from jumping a 1960 Valiant to a 2023 Gladiator.

In any case, yeah, if N3 is blown or the PCR is fried and the NO contacts are no longer closed or are burned, the aux can't charge and with the PCR contacts fried, it's no longer connected to the main battery so even the main battery can't boost the aux battery voltage up.

N3 is 150 amps - big spark needed to blow that one.

 

[KR36]

Thanks for the information! I didn’t end up jumping it the second time. The error codes wouldn’t allow any type of crank. The dash just lit up like a Christmas tree. Had to pull the hidden lever to get it into neutral so the tow truck drive would get it on the flat bed. It’s just weird because I had picked up the truck that morning from the dealership and it’s started just fine. Ran a few errands and then went to work. When I went to leave and used my remote start it fired right up. But once I unlocked using the passive entry the engine cut off and wouldn’t allow me to do anything. I hadn’t touched anything under the hood to cause any fuses to blow if that’s what even happened. A few weeks prior I had a few days where the passive entry didn’t work and another day where the remote start didn’t work. It seems like it is a module issue to me? Thoughts.

 

[ShadowsPapa]

Thanks for the information! I didn’t end up jumping it the second time. The error codes wouldn’t allow any type of crank. The dash just lit up like a Christmas tree. Had to pull the hidden lever to get it into neutral so the tow truck drive would get it on the flat bed. It’s just weird because I had picked up the truck that morning from the dealership and it’s started just fine. Ran a few errands and then went to work. When I went to leave and used my remote start it fired right up. But once I unlocked using the passive entry the engine cut off and wouldn’t allow me to do anything. I hadn’t touched anything under the hood to cause any fuses to blow if that’s what even happened. A few weeks prior I had a few days where the passive entry didn’t work and another day where the remote start didn’t work. It seems like it is a module issue to me? Thoughts.

My only thought is not a happy one - too few dealership techs know squat about electrical systems.
Maybe it's a good thing I'm out of the business and not having to work around "techs" i a shop these days. I'd go nuts with the lack of depth of knowledge. It's a thankless job, no real room to advance, and too often it's not great pay so I can see why few stick with it and put in any real effort, but still.

Anyway, fairly simple things to check that they should check before they think too hard (and blow the fuses in their heads) -
Double check that all fuses are pushed firmly into the fuse panel under the hood.
If they got to the aux battery by removing the PDC/fuse panel instead of the book way, through the fender liner, who knows what might have gotten knocked loose.
And there's a set of connectors behind the glove box inside the truck that carry CANBus communications and there have been issues with connectivity there.

Since you noted weird issues prior to being at the dealership - it's unlikely anything they did during battery replacement. It's more likely a connector issue like fuses, the connectors behind the glove box, that sort of thing.
Many of the errors in your screen shots are communication issues - so the connectors at the firewall, behind the glove box is one thing to look at.
Did they do any PCM flash or any updates?
I see handshake error messages - can be caused by connection issues, but also by a flash where the thing has decided the modules don't trust each other. There's a process for the dealer to perform to fix that after a flash.

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