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Computer Glitch / Battery Problem

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My Jeep – 2019 Rubicon JL 2 door, 2.0. No aftermarket mods because I am doing an experiment to see if a Jeep can go past 120K miles without a catastrophic failure. I am on my 6th Jeep and this, unfortunately, may be my last one. So many problems.

The Problem – After about 30 minutes of driving, the dash board goes crazy. It lights up with about 10 errors. The shifter lights blink. You lose power steering, you lose power brakes, most electrical in the vehicle is unusable and when you shut the Jeep off, it will not start again. Errors include “Auto Park Engaged”, “Service Shifter”, “Door Open” and a bunch of others that I don’t remember but they all happen at the same time. This situation is very dangerous because you are normally stuck on the side of the road without being able to use your hazards and you are completely immobile. The shifter lights blink off and on and all turn white (no yellow marker). Dash lights constantly display error codes. Sometimes that Jeep stalls while you’re driving.

Temp Fix – If you wait 30-60 minutes the system will reset itself and you can start the Jeep. You will be able to drive another 15-30 minutes before it happens again. The driving duration increases as time passes and you use the vehicle more. This will go on for a few days until it works itself out and eventually stops (Typically 2-3 days).

Things I’ve tried:
1. Disconnect the battery and wait 5 minutes. Sometimes this helps and sometimes it doesn’t. This morning, I had to do this to get it started.
2. Use a handheld to reset the codes. Sometimes this works
3. Replacing the battery. A year ago I had this issue and had the battery checked twice. The first person said the battery checked out OK. The second person (a few weeks later) also checked it and at first glance, everything seemed fine. Then they saw the cranking amps was low. I replaced the battery and the problems completely stopped for a few months.
4. Checking electrical connections for condensation or corrosion. I took apart the fuse box and many other electrical components and found no issues.
5. Searching for a short. There is no short. My battery does not drain and can go months without this problem happening. If there were a short, the problem would be consistent.
6. I’ve checked all of the battery terminal connections and the ground nuts to the frame. All tight.
7. Fuses and relays – I’ve checked all of the fuses and relays to make sure they seated correctly. They weren’t and I fixed them. Then they seemed to pop out again. I have fixed them many times and the Jeep still has the problem. I also don’t have any blown fuses.

WHAT I HAVE NOTICED – This problem has happened to me about 5-6 times and normally lasts a few days. Since this is my daily driver, I do not have time to bring it back to the dealer. My local Jeep dealer requires that I leave the Jeep there for 7+ days before they will even be able to look at it. From other posts that I have researched with this same problem, the dealership mechanics have not been helpful. This is probably because the Jeep needs to be driven 30+ consecutive minutes before the problem will act up.

Here is what I have found that, I believe, causes the problem to start in the first place. So, I am an avid fisherman. I spend about 20-30 weekends a year on Texas beaches. I fish for sharks and I use a drone to deploy my bait 300-500 yards. My drone has three batteries and when they need to be charged, I use a battery charger that connects directly to my Jeep battery. Now, as long as I turn my Jeep on and let it run (Before and during) I will not have any issue AT ALL. If I forget to turn the Jeep on first, and allow the charger to pull directly off the battery, even for only 5 minutes, The Problem will happen every single time. Yesterday, I accidentally forgot (for about 10 minutes) but I let the Jeep run for 4 hours after that. The problem still happened.

I am thinking that the temporary decrease in battery voltage may be causing problems with the main computer. Anyone else having this issue or know a better fix than sitting on the side of a pitch black, Texas country road waiting for 30 minutes and wondering how close you are to where the real life Texas Chainsaw Massacre happened?
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I assume you only replaced the main battery. You did not mention the auxiliary battery. Do you have eTorque? If you don’t have eTorque you have a secondary battery the size of a motorcycle battery as well. To change it you need to remove the fender.

I would replace both batteries and reseat all the fuse.
 

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My friend has a similar problem. She has a 2019 (not rubicon) manual transmission, 4 door, obviously not mine so i don't know the exact trim or anything or motor. She has lost power steering while all the lights come on, but she was able to pull off to the side and just restart right away. She took to dealer, they said this is often triggered by jump starting the car and a second battery. If you leave it sitting for a while (days-weeks?) it can also happen without a jump. She DID leave it for about 2 weeks at one point and the problem started shortly after this. Dealer had no advice, but cleared a lot of codes after this. I'm wondering if there's a TSB or if there will be one eventually. Has anyone else experienced this and had it resolved?
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I assume you only replaced the main battery. You did not mention the auxiliary battery.

I would replace both batteries and reseat all the fuse.
I will pass this along as well.
 

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Discussion Starter · #4 ·
I assume you only replaced the main battery. You did not mention the auxiliary battery. Do you have eTorque? If you don’t have eTorque you have a secondary battery the size of a motorcycle battery as well. To change it you need to remove the fender.

I would replace both batteries and reseat all the fuse.

Thanks for this. I didn’t realize that I had an auxiliary battery. I’ve heard about it but I didn’t see one so I assumed that I didn’t have one. Who knew they would bury so far into the vehicle and make it horrible to access? So, I watched a few videos on how to replace the battery and what happens when the battery goes bad and I am optimistic that this may fix the problem I am having.

The only thing that still stuck in my head is “if the auxiliary battery is bad, why don’t I have The Problem all of the time?”

Recently, The Problem happened on Sunday and lasted until yesterday (11/6 thru 11/7). On the drive home from work yesterday, all of a sudden, the quirks fixed themselves and the check engine light finally shut off on its own. I can probably go another few months without The Problem happening again.

I also need to do some reading on how this auxiliary battery is used and the circuitry. Is it run in series with the main battery (Supplementary) or is it a separate circuit? Does the alternator charge the aux battery? What accessories are run off the aux battery? So many questions
 

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The main purpose of the auxiliary battery has to do with ESS. It is not a simple secondary battery wired in like older diesel trucks with two batteries. It is managed by a computer.

The bottom line is that it is poorest implement of ESS ever.

The reason your problems aren’t continuousis because it isn’t accessing the auxiliary battery all the time.

This convoluted setup is why I think the JL’s with eTorque are better because they use a large 48 volt battery instead. Even though the 48 volt battery is expensive and there are additional cooling lines for it, I still think this probably better than the problematic system with the small auxiliary battery that requires fender removal to change.

I see numerous threads on another forum about problems with this auxiliary battery system but I don’t recall seeing a single problem associated with the 48 volt eTorque system despite a lot of speculation that it is going to be a very problematic system.

I have no skin in the game as I am still rocking my 2014 JKU with 113,000 miles. It just the damn engine ticking that is driving me up the wall.
 

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You can also access the auxiliary battery by pulling off the fusebox, that might be less annoying than removing the inner fender. It's all bolts.
 
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