Problems

[James34]

Have a 2018 jlu rubicon with 60k miles. Bought it used 6 months ago. A few weeks ago it started throwing codes dealing with 4 wheel drive, auto start stop disabled, service transmission, don’t shift out of drive. It also lost power steering and the wipers came on. Traction control was out. Reading a few threads I jumped to the fuse box and started checking for loose fuses and there was a few but it’s not like they were barely connected. Just not pushed in quite all the way. I put a multimeter in it and had power through all of them and the battery was charging fine. I closed the hood and mostly everything was fine. Just the check engine light was on. Drive it to auto zone ram the code it was nothing serious, unfortunately I lost what code it was. Anyway the code cleared it’s self the next morning. So I thought cool I fixed it. Had to drive it to Utah for a funeral and it made it out there no problem. But coming back it ran for an hour then did the same thing. So I pulled over checked the fuses did the same push them down but didn’t find any loose ones. It started fine and was all good again. So got back in and started driving again. This time it made it to grand junction and did it again. My wife need to get back to work the next day and it was 4th of July weekend so I found the only place that would answer the phone dropped it off and rented a car. That mechanic had it for a week but couldn’t get into the computer because Chrysler security so i drove back up the following weekend and moved it to a jeep dealer only now everything ram fine and no check engine light. Told the dealer all the problems they ran the stores codes saw something like 150 and started trying to find the problem. Well long story short they couldn’t find anything wrong. So I picked it up the next weekend and drive it home completely fine. Well this morning my wife try’s to take it to work and it won’t shift and all the problems are back. So far I’ve pulled of both a pillars looking at the wording there I’ve pulled off the panels on the drives and passenger foot wells to look at the grounds and wiring there. I’ve glanced around the Sway bar wireing and haven’t found anything there either. Any suggestions? I’ve uploaded what the dealer looked at. I’ll try to upload a video of the dash when it happens but the file is to large so I’ll look for hosting site

Sponsored

 

[RZ.]

How's your battery?

I've been reading about that causing a variety of issues.

 

[James34]

How's your battery?

I've been reading about that causing a variety of issues.

Putting a load tester on its reading good with the car off at 11.5. Off and not under load it’s 12.9. Running its charging at 14.3. As far as the aux battery no idea

 

[Reinen]

I'll 2nd that batteries diagnosis as well. Is your Auto Stop/Start working? That's usually the first thing that stops working with bad batteries. Then comes funky random codes and it may not start. If they are the original batteries they are at typical end of life.

If you replace batteries, always replace Main & Aux at the same time. If you don't the other battery can quickly kill your new battery.

 

[RZ.]

I recently had battery problems with the 2018 I purchased just months ago, too.

Because the batteries are wired together, they give each other a boost even as one or the other is dying. My main battery was testing good voltage-wise, but it was certainly not good & a replacement took care of me. I didn't experience the broad spectrum of issues you are, so don't want to mis-represent that - just offering up what little I know, for reference.

 

[Htfan]

Putting a load tester on its reading good with the car off at 11.5. Off and not under load it’s 12.9. Running its charging at 14.3. As far as the aux battery no idea

Does the JLs dash voltage ever go below 14.3v when the engine is running? If not, I would suspect one or both batteries may have an issue. I would test both batteries (main & Aux) individually.

NOTE - the dash displays charging voltage when the engine is running. So if it's always high then the health of the batteries is in question.

 

[James34]

Does the JLs dash voltage ever go below 14.3v when the engine is running? If not, I would suspect one or both batteries may have an issue. I would test both batteries (main & Aux) individually.

NOTE - the dash displays charging voltage when the engine is running. So if it's always high then the health of the batteries is in question.

Pretty sure it drops to 13 something after a while. Not really looking forward to pulling the aux bat out. If I test through the main bat leads is that sufficient? Should I even be putting a load tester on that little battery? Just look at voltages?

 

[RZ.]

Since I didn't replace mine - I was planning to pull a fuse and disconnect a negative cable to isolate my aux. battery, based on this thread:
https://www.jlwranglerforums.com/forum/threads/jumperless-aux-battery-bypass.95945/

That could be helpful in getting a better read on the main, but I have no idea how you would test one for amperage/load capacity ... other than carrying it to the local parts store for a test.

To this non-electrical guy, it seems that's where the problem lies: lots of systems demanding full power and anything less is big, bad juju.

 

[James34]

I'll 2nd that batteries diagnosis as well. Is your Auto Stop/Start working? That's usually the first thing that stops working with bad batteries. Then comes funky random codes and it may not start. If they are the original batteries they are at typical end of life.

If you replace batteries, always replace Main & Aux at the same time. If you don't the other battery can quickly kill your new battery.

Auto start stop has worked fine except when it throws the code. Starts fine no problem

 

[zrickety]

If the batteries look original, I would replace them. Even if they are newer, try unhooking both (aux too) and wait 10 minutes. This will completely reboot everything. Then reconnect, drive it and see.

 

[RZ.]

Batteries have been fresh on my mind lately, so the first thing I thought of ... sorry if it's the wrong tree!

On a similar note, tho - check your grounds. I've had that problem on other vehicles & it's rarely the first thing to come to mind, but certainly an easy check.

 

[Remorseless]

Honestly, if both batteries are original, I'd just probably start with replacing them given the age of the vehicle and the fact the batteries are probably on the way out anyway. JLs are super temperamental with regards to battery health for either battery. Anything showing up as an electrical gremlin with the batteries in the 3-5 year+ range, that'd probably be my first step if for no other reason than to eliminate them as the cause.

 

[James34]

Batteries have been fresh on my mind lately, so the first thing I thought of ... sorry if it's the wrong tree!

On a similar note, tho - check your grounds. I've had that problem on other vehicles & it's rarely the first thing to come to mind, but certainly an easy check.

Yeah that’s where I started looking. Someone posted a wiring diagram so I’ve been trying to chase grounds down. The 4 grounds in the front foot wells are tight (put a wrench on and checked) and look like no corrosion. I’m leaning towards rubbed wires shorting but looking at grounds at the same time. Was hoping for specific places to look. Seems like most of the fixes from dealers seam to be new wiring harness but the ops don’t specify what harness and where other than one by a heat shield near the transmission, one from the sway bar rubbing on the ac condenser, the a pillar wires, and the foot well grounds. So I have been checking this first with out much luck

 

[Old Dogger]

Yours being a 2018. If they are original, they both need to be replaced. Ours is also a 2018, so we replaced both of them, with AGM batteries.

 

[OBD]

As others have said.I would replace batteries and check the grounds.

Sponsored