2021 GLADIATOR 3.0, U0101 CODE LOSS COMMUNICATION WITH TCM

[Up4jules]

So about a week or two ago, I was pulling into a parking lot when all of a sudden the check engine came on, then the service throttle control lights, then the jeep went into limp mode. Then the message shows on the dash Service Transmission Continue in D. Do Not Shift or Turn Engine Off, Until You Reach a Desired Location. You May Not Be Able to Shift Again Until Serviced. So I stopped and all of the lights lights on the shifter was bright orange. I couldn't shift the jeep into park, it wouldn't go into any other gear. Tried to shut it off, but I wasn't able to. It was stuck on ACC, and it wouldn't restart. So, all of the lights, radio, etc was stuck on. After some research, I still couldn't find anyone who had figured this out. Since then, its been internment since then. Last night, it did it again, I changed the fuse, drove maybe 5 feet and it all happened again. Changed the fuse again, blew again. After sitting for awhile, I replaced the fuse again, cleared the codes, tried to start it, it didnt even do a full try, then on the dash it said pre-heat diesel. What the heck! It was 70 degrees outside, at night, but still, it took it about 5 minutes of pre-heating before it finally started, and I immediately put it into reverse, backed out, then drove home, all the while making sure to keep my RPMS up so it didn't stall out. I made it home, fuse intact. So the codes its throwing U0101, P026C P1614, P0191. Those are intermittent as well. Recently replaced the MAP sensor, The fuel rail sensor is next, it's just not as easy for me to get too. The last year it has had little things here and there like once every now and then, when I come to a light or just idling it will stall. Had the service throttle control red bolts come on and off, again, intermittent. When you get on it, it feels like its clogged, just a quick lag. The fuse that keeps blowing is F08, for the TCM.

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[vicsvx]

Just out of curiosity... Have you checked if the wiring harness is rubbing on the EGR exhaust tube?
https://www.jlwranglerforums.com/forum/threads/service-shifter.24255/page-7

https://www.jeepgladiatorforum.com/...-harness-service-shifter-error-message.80103/

 

[Neutrino]

Sounds like your wiring harness is rubbing on something and wires are shorting on something. Check the wiring harness that runs down along your exhaust by the battery and firewall.

 

[Up4jules]

Just out of curiosity... Have you checked if the wiring harness is rubbing on the EGR exhaust tube?
https://www.jlwranglerforums.com/forum/threads/service-shifter.24255/page-7

https://www.jeepgladiatorforum.com/...-harness-service-shifter-error-message.80103/

No, I haven't checked that, but that makes a whole lot of sense. My next move was going to be a check of the wires to see if rubbing, chafing, etc. I had seen it on YT, and was dreading doing that. But this gives me more of a solid place to start. I will check first thing in the morning. Thanks so much

 

[Up4jules]

Sounds like your wiring harness is rubbing on something and wires are shorting on something. Check the wiring harness that runs down along your exhaust by the battery and firewall.

I appreciate your suggestions, as I had seen online about just start troubleshooting by checking all the wires. This sounds alot more doable. I will check first thing in the morning. Thank you

 

[Neutrino]

Are you sure it's F09? Diagrams show F09 as a spare. F08 should be a blue 15amp for your TCM.

 

[m3reno]

Do the diesels have a canbus block? It sounds like a short but I've read that some people had the canbus block issues with the regular gas vehicles where they lost communication and would get random lights pop up on their dash. it's behind the glove box.

 

[Up4jules]

Are you sure it's F09? Diagrams show F09 as a spare. F08 should be a blue 15amp for your TCM.

Your right, thanks. I mistyped.

 

[Up4jules]

Do the diesels have a canbus block? It sounds like a short but I've read that some people had the canbus block issues with the regular gas vehicles where they lost communication and would get random lights pop up on their dash. it's behind the glove box.

Yes, I just did some more research and it absolutely does! And when I was reading the different things that it causes when the star connector goes bad, it mentions the dash lights, cannot shift into park, etc. Thank you! I will be getting started with these suggestions first thing in the morning!

 

[vicsvx]

I had the dash light up randomly when driving over bumps... Found the wiring harness chafing on the EGR exhaust tube. I tucked it between the heat shield and haven't had idiot lights or warnings come on since

 

[Not2Late]

This sounds exactly like the issue I had on my gas 2021 Mojave. I would definitely check the rubbing wiring problem mentioned by others that effects some of the diesel models. But this may be worth a check as well.

There is a big wiring connector behind the passenger fender liner on the firewall. Lots of power/communication wires run through it. One is a communication/power wire that runs to the TCM. I had a good tech at the dealership figure it out. It was a bad wire/connection for the TCM power/commumication within the big connector. It was out of warranty, so he ran a bypass wire and shrinkwrapped it. Problem solved! Here is the work order:

 

[Up4jules]

I had the dash light up randomly when driving over bumps... Found the wiring harness chafing on the EGR exhaust tube. I tucked it between the heat shield and haven't had idiot lights or warnings come on since

You know, one of the times it popped the fuse was when I hit a bump, the dash lit up and I was in limp mode again. I really hope it's something like this, thanks so much.

 

[Up4jules]

This sounds exactly like the issue I had on my gas 2021 Mojave. I would definitely check the rubbing wiring problem mentioned by others that effects some of the diesel models. But this may be worth a check as well.

There is a big wiring connector behind the passenger fender liner on the firewall. Lots of power/communication wires run through it. One is a communication/power wire that runs to the TCM. I had a good tech at the dealership figure it out. It was a bad wire/connection for the TCM power/commumication within the big connector. It was out of warranty, so he ran a bypass wire and shrinkwrapped it. Problem solved! Here is the work order:

Thanks for sharing that. Reading your symptoms, its like me trying to explain what is going on with this one. What floors me is that this would be an ongoing thing, that Jeep wouldn't see the patterns and fix it. I sure appreciate your help, I'm just about ready to dive in and see what I come up with.

 

[Up4jules]

So I am about to go out and start working on it. Thanks guys for all of your suggestions, at least I have a direction to start at and go from, instead of just sticking a road flare under it and calling it a day, lol. I will update when I have found some answers. Again thank you!

 

[vicsvx]

You know, one of the times it popped the fuse was when I hit a bump, the dash lit up and I was in limp mode again. I really hope it's something like this, thanks so much.

Watch this video and check yours when the engine cool.

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