4.88 regear issues on 2024 JLU

[jimmyjim]

I have the most recent recall on my Jeep and have no problems with 4.56 gearing. I didn’t even need to reprogram. I used JSCAN to set the ratio after regearing and performed the relearn TSB.

I will try this tomorrow, what’s the relearn TSB?

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[cthomas31]

What was the final outcome of this? I have a 2022 Sahara that was just regear to 4.56, got the lighting bolt, limp mode, gear sensor code and hot clutch warning. Jeep said they can’t figure it out. I asked them to just load their 4.56 options, such as the high tide comes with. They said there is not way to input gear ratio into ecu. I find this to be crazy. I’ll be headed to Jeep tomorrow to speak with someone in person. I’ll try JScan, maybe that will stick. I have called hemifast about reflating the original management back. Had the recall done last year. Didn’t know it included new management flash. Thought it was just a new
better clutch

Jeep should be able to reprogram it. They did it for me based on the rubicon gearing. Keep pushing until they fix it.

 

[AlgUSF]

I will try this tomorrow, what’s the relearn TSB?

So.... I used my JSCAN app and it showed a P08A6 code in the advanced scan which I had to scan for while the engine was running and Auto Start Stop indication was displayed. I did a little research and I needed to perform an "M/V Relearn Procedure" which calibrates the engine speed to wheel speed ratios.

https://www.jlwranglerforums.com/forum/threads/jl-m6-relearn-procedure.53662/

There is a Jeep service bulletin on it out there on the interwebs. Basically disconnect the entire negative battery post stack for a half hour, reconnect it and get into 6th gear between 40 and 80mph, keep a decent steady pressure on the accelerator for 20 seconds and voila done.

Quoted is my post from another thread, I'm trying to find the actual TSB again.

EDIT: Summit racing has a copy of the Z-Automotive procedure
https://static.summitracing.com/global/images/instructions/zau-ztzrjlm_nb.pdf

 

[jimmyjim]

I had to have the ecu reflashed with “as built” spec software, then go in and change the tire and gear settings. Now it runs. If anyone is in need of this, these guys figured it out in 48hrs. Call them.

https://jjoffroad.com/

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