Anyone experienced codes like these?

[Papa Bear]

Once again I am turning to the Gladiator community to help me suss out some major CEL and related issues.
I have a 2020 JTR 3.6. The mods I have are an AEV 2.0 spacer lift, BFG KO2 37x12.5 R17 (factory wheels), AEV steering damper and AEV Geometry Correction Brackets. Until a few days ago I was using the Tazer JL Mini to configure everything.
I sent Tazer back for a replacement because I was getting multiple codes while driving that I believed were related to the Tazer failing even though I had 10 months without issues and upgraded the software as new versions came out. I removed the Tazer this past Thursday, unmarried it, disconnected the negative battery for 15 minutes then reconnected negative terminal and followed all of the instructions ZAutomotive told me to.
Today while driving it sans Tazer, I got all of the same error codes plus a new shiny one called “Service Shifter.”
This has been a constant situation for the past two months but progressively gotten to be more frequent and apart from being a major cause for concern it’s also been hard to pinpoint and a major pain in my a$$!
While driving I would get the ABS, Traction Control, Blindspot unavailable, Brake light and loss of power steering. When I pulled over and put the Jeep in Park, I couldn’t get it out of Park. Without the Tazer I also don’t know how to clear the DTCs. I shut the engine off for a couple minutes and was able to shift into Drive but the “Christmas tree” of lights remained…eventually after slowly creeping along the back road home all the lights went off except for the traction control light and the check engine light. The “Service Shifter” warning was most troubling as was the loss of power steering.
I’m getting the following codes and could really use some help from anyone with knowledge on what this issue could be caused by.

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[Lost1wing]

I have a 2020 and I have a Tazer installed with the latest update. I have not had any issues like what you are having. The only help I can offer is that I have a Duramax truck they gave me a handful of u codes after a cold weather start that was very sluggish. I slapped in a couple of new batteries and had no reoccurring events. Now with your JT being a 2020, I would assume original batteries, could be part of your problem. I wish someone with a similar experience on their JT would chime in.​

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[Lunentucker]

I'm guessing it's batteries.

 

[ShadowsPapa]

I'm "guessing" it's the bus connectors back of the glove box.
U01 and U11 have been CAN bus communication problems in my experience. I've had a few of them. Resolved by dealing with that star connector behind the glove box.

 

[Lunentucker]

Definitely batteries.

 

[Papa Bear]

Definitely batteries.

I will replace both of the batteries but in my limited understanding the alternator would keep them charged while driving, no?
What is a proper voltage reading for a strong battery so I can compare mine please?
Also, under the diesel JT platform someone posted a wiring harness out side of the firewall was causing issues. I will look for a link to that but could it be an issue for gas versions? Where would I find this wiring harness?
thanks everybody for offering advice.

 

[Lunentucker]

I will replace both of the batteries but in my limited understanding the alternator would keep them charged while driving, no?
What is a proper voltage reading for a strong battery so I can compare mine please?
Also, under the diesel JT platform someone posted a wiring harness out side of the firewall was causing issues. I will look for a link to that but could it be an issue for gas versions? Where would I find this wiring harness?
thanks everybody for offering advice.

I was just messing with @ShadowsPapa
Get it checked by someone knowledgeable.
You can't just stick a meter on the main battery on these because of the goofy lawnmower battery that's tucked away under the fusebox.

 

[Papa Bear]

Just curious if these codes and issues would manifest while driving the vehicle. The gauge on the dash says that my battery is betwixt 14.4-14.6 V except when I put the truck in reverse then it dropped to 12.6...WTF? Not sure if it's related and I will still look to replace both batteries but curious why the battery was the first suggestion versus say, a fuse(s) or random sensors.
Thanks to all who have some advice.

 

[Papa Bear]

I'm "guessing" it's the bus connectors back of the glove box.
U01 and U11 have been CAN bus communication problems in my experience. I've had a few of them. Resolved by dealing with that star connector behind the glove box.

Did you have a loose connection on this CAN Bus or was it a loose screw? Just want to narrow it down .

 

[Papa Bear]

Definitely batteries.

I just replaced both batteries and the issue came back after 400 road miles. Now it happens every time I drive it. 3 occurrences on 14 total road miles today. OBD2 scanner from AutoZone said ABS sensor and Vacuum pump need to be replaced…huh? Ugh, getting pissed at this.

 

[ShadowsPapa]

I just replaced both batteries and the issue came back after 400 road miles. Now it happens every time I drive it. 3 occurrences on 14 total road miles today. OBD2 scanner from AutoZone said ABS sensor and Vacuum pump need to be replaced…huh? Ugh, getting pissed at this.

Generic parts store scanners don't always cut it - aren't always accurate. And if the problem is that bus start connector back of the glove box, it's going to trick scanners most of the time because they can't communicate.
I took screen shots of what JSCAN gave me for codes to the dealer, told them of the symptoms, etc. Next thing I know - it's fixed while they fixed the misfire issue by forcing a cam/crank diff relearn.
I know they had the glove box out and worked in that area - passenger seat was back farther and a couple of things from the glove box were moved (I know what order things are in, in there) but it was never written up. All the service advisor would say was "yeah, he worked on that too"
A scanner can only work if it can communicate with the various modules. If there's a bus communication issue, then the scanner may assume the worst.
Don't rely on parts store staff or tools in every case. I won't even let them test a battery.

 

[IanNubbit]

Honestly looks like a program/communication issue and not voltage related. Gonna be hard for you to repair yourself. Probably going to need multiple individual ECU resets

 

[am1978]

I just replaced both batteries and the issue came back after 400 road miles. Now it happens every time I drive it. 3 occurrences on 14 total road miles today. OBD2 scanner from AutoZone said ABS sensor and Vacuum pump need to be replaced…huh? Ugh, getting pissed at this.

Go check the other thread you posted related to this one. You need to flash the PCM. You could need the vacuum pump or an o2 sensor replaced. Are either or both of your ESC or ESS not working?

 

[Papa Bear]

The ESS works because I’ve purposely slid while the light was on and I can still turn the ESS on or off and get a separate light on dash to reflect input of that.
The Service 4WD! Light also comes on and the Service Shifter light also, the speedometer goes all the way down to 0 mph with the ABS light also on. All of these quirks that don’t change the way the truck drives at all but if I we’re to put it in Park…it won’t shift out of Park without a using tazer to clear all DTC then full reboot.

 

[kooltoys]

a known issue is a wiring harness under the passenger fender can touch the exhaust and melt wiring. Its worth 2 minutes to look up from the ground just behind passenger fender, above the exhaust. seems a harness attacthment point can come loose causing all kinds of issues!

edit: this maybe a diesel only issue iirc

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