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HELP! Electrical issues. :(

SabraLanae94

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I have a 2021 2.0 Turbo model sport s that has been the absolute bane of my existence since I purchased it new in 2021 I have had so far to replace the fuse array had to take it to the dealership two different times for electrical issues the first issue was service transmission wouldn't come out of park couldn't turn on or off and all the lights were lit up on the shifter. The dealership fixed that problem in May of this year I can't remember what they said the issue was but it was something to do with a wire being loose or something. Fast forward to December I am now having a service shifter error with every single light on my Dash flashing gauges going crazy etc. All out of nowhere someone mentioned the can bus plug in but I'm not sure if that's what I'm dealing with any help would be great I have about 160,000 Miles on it.

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HeN2O2

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I had two loose wires in the PCM harness that made all sorts of weird things happen and gave the appearance that it was a can bus problem. I haven’t had any problems since the wires were repaired. Unfortunately, it took a long time and effort to find the problem with a lots of wasted attempts, including replacing the PCM. A mechanic stumbled onto the problem when he was just looking at the engine and set his hand on the PCM harness and set off a lot of errors that were repeatable.

One guaranteed way to fix the problem involves the use of thermite grenades.
 

dchemphill1

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If not battery (be sure to load test it) then out of nowhere I would lean canbus. You have certainly put the miles on that 2021. Sounds like mostly electrical issues, the worst. The engine and transmission have treated you well.?
 
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SabraLanae94

SabraLanae94

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Your canbus is behaving badly. It could be a dozen different things. Bad batteries, loose or shorted wire, bad module, and more. These are difficult to track down on your own. I would start with checking the batteries first.
Here is the notes from the dealer from may.

Jeep Wrangler JL HELP! Electrical issues. :( 20251204_140354


Jeep Wrangler JL HELP! Electrical issues. :( 20251204_140444
 

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SabraLanae94

SabraLanae94

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I had two loose wires in the PCM harness that made all sorts of weird things happen and gave the appearance that it was a can bus problem. I haven’t had any problems since the wires were repaired. Unfortunately, it took a long time and effort to find the problem with a lots of wasted attempts, including replacing the PCM. A mechanic stumbled onto the problem when he was just looking at the engine and set his hand on the PCM harness and set off a lot of errors that were repeatable.

One guaranteed way to fix the problem involves the use of thermite grenades.
Here's the notes from the dealer I still dont know exactly what they did but it fixed it from may. I am not getting a service transmission code anymore like when they fixed it before. Only service shifter and all gauges losing it.

Jeep Wrangler JL HELP! Electrical issues. :( 20251204_140354


Jeep Wrangler JL HELP! Electrical issues. :( 20251204_140444
 
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SabraLanae94

SabraLanae94

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If not battery (be sure to load test it) then out of nowhere I would lean canbus. You have certainly put the miles on that 2021. Sounds like mostly electrical issues, the worst. The engine and transmission have treated you well.?
I replaced the rear end because it blew apart for no reason at 65k miles. So far beyond electronics the motor has been sound and transmission is smooth.
 

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The repair they did is not uncommon. There is a connector behind the front passenger wheel well that can become problematic with open circuits. The two canbus lines go through that connector and can become intermittent, causing havoc to the module communications.

But you now have another similar problem, or possibly the same problem. Seems they fixed it once, why not take it back there? They seem competent.
 

tk1700

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I had similar issues with a 2019 JLU and they all went away after I replaced the Canbus.
 

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SabraLanae94

SabraLanae94

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The repair they did is not uncommon. There is a connector behind the front passenger wheel well that can become problematic with open circuits. The two canbus lines go through that connector and can become intermittent, causing havoc to the module communications.

But you now have another similar problem, or possibly the same problem. Seems they fixed it once, why not take it back there? They seem competent.
Its 6-800 dollars to fix if its that same thing. I dont have that right now.
 

Heimkehr

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Sabra,
Were both batteries replaced earlier this year? If your Jeep has Electronic Start/Stop, aka ESS, there's a second, smaller battery under the fuse box* that should be replaced at the same time the larger main battery is replaced. The ESS battery tends to wear out first, meaning it will cannibalize the main battery until both are replaced. A failing battery can often manifest as the source of seemingly unrelated electrical issues, such as a variety of warning lights illuminating at the same time.

*AKA the PDC, or Power Distribution Center (what you might've referred to as the "fuse array".)

The CANBUS terminals are the green and white plastic blocks behind the glove box door. Replacing both has occasionally solved similar electrical issues when other owners had the same dashboard display that you're currently seeing. Consider attending to them as the logical next step.
 

SlickRicksWilly

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Sabra,
Were both batteries replaced earlier this year? If your Jeep has Electronic Start/Stop, aka ESS, there's a second, smaller battery under the fuse box* that should be replaced at the same time the larger main battery is replaced. The ESS battery tends to wear out first, meaning it will cannibalize the main battery until both are replaced. A failing battery can often manifest as the source of seemingly unrelated electrical issues, such as a variety of warning lights illuminating at the same time.

*AKA the PDC, or Power Distribution Center (what you might've referred to as the "fuse array".)

The CANBUS terminals are the green and white plastic blocks behind the glove box door. Replacing both has occasionally solved similar electrical issues when other owners had the same dashboard display that you're currently seeing. Consider attending to them as the logical next step.
@SabraLanae94 This 👆 is the best place to start especially if you have not yet replaced the ESS battery yet. There are threads on this forum on how to bypass the secondary battery and that could be a free way to test if you don't have the ability to test the battery itself.
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