Problems with the 392 Rubicon

[EBYCREEK]

I have the same problem with mine on the passenger side. Boot has a small tear right in the middle of the boot.

 

[Centexcpa]

Inherently, most new editions have more problems than the following editions. I understand the 392 Rubicon is not considered completely new as the JL body style has been around since 2018, the engine since 2011, and the transmission since 2014 (at least the generation in the 392). However, the 392 Rubicon is a new trim/configuration and many modifications had to be done to fit all components well.

This thread is to help each other out and hopefully minimize serious issues.

So far, from reading other threads/forums:

The fuses not seated well in some 392s have caused some electrical problems.

Wires too close to heat sources have also caused electrical problems.

As the title says, what problems have we encountered?

I am having a problem the local dealership cannot solve as of yet. Periodically (more and more frequently now) when accelerating, even mildly, the Jeep will stall like it has hit a rev limiter or speed limiter. I get messages that say Adaptive Cruise Control inoperative, Service shifter, and service Electronic Stability Control. Yellow warning lights stay on. When I turn the engine off and restart, the codes clear but stay stored. I have checked all of the fuses, all are okay. The dealership had me bring it in with the codes still active so they could get a live read, say they are researching, but have not come up with a solution after nearly a couple of weeks. Very frustrating.

 

[RugbyRef]

I am having a problem the local dealership cannot solve as of yet. Periodically (more and more frequently now) when accelerating, even mildly, the Jeep will stall like it has hit a rev limiter or speed limiter. I get messages that say Adaptive Cruise Control inoperative, Service shifter, and service Electronic Stability Control. Yellow warning lights stay on. When I turn the engine off and restart, the codes clear but stay stored. I have checked all of the fuses, all are okay. The dealership had me bring it in with the codes still active so they could get a live read, say they are researching, but have not come up with a solution after nearly a couple of weeks. Very frustrating.

Could this be the dreaded "fuses not seated properly" issue? I couldn't find a similar topic in the search function, but I know it's in there (or perhaps in this thread?).

Edit - Whoops...missed that you checked the fuses already.

 

[@JC]

Sounds like the fuses (which you checked) or an electrical ground issue somewhere.

 

[Smess]

Jeep runs on fly by wire which is actually quite scary. For obvious reasons when the Jeep sense anything to do with acceleration or anything that makes the Jeep go it can not fail or the results can be disasterous. All you named have to do with movement or in other words systems shutting down or stopping to stop disaster. Cruise control, traction, and even shifter which controls overall movement (P or N vs D). I would bet some sensor related to speed or movement is failing but I would think a simple plug in to the dealerships computer would answer the question immediately. Silly question but does the Jeep have any mods? Including even a tire calibratiom plugin etc

 

[Smess]

As great as it is to get trouble shoot answers in seconds or mins with all the sensors a small nick in a wire can cause pure chaos. Had a friend with a brand new diesel with a wire that had insulation torn and the short from exposed wire or change in voltage range can cause all kinds of hell. And there is miles of wire in the vehicle

 

[Centexcpa]

Jeep runs on fly by wire which is actually quite scary. For obvious reasons when the Jeep sense anything to do with acceleration or anything that makes the Jeep go it can not fail or the results can be disasterous. All you named have to do with movement or in other words systems shutting down or stopping to stop disaster. Cruise control, traction, and even shifter which controls overall movement (P or N vs D). I would bet some sensor related to speed or movement is failing but I would think a simple plug in to the dealerships computer would answer the question immediately. Silly question but does the Jeep have any mods? Including even a tire calibratiom plugin etc

No, completely stock. I did have a base plate installed so that I can tow behind my motorhome, maybe a wire got nicked there somewhere. The dealership is going to take it in again Monday and start looking at it again.

 

[BenLandry]

I saw a black 392 getting towed in Humble, TX a few minutes ago. Being towed backwards with front tires only on ground by a tow truck. Got me thinking of that’s correct, I guess if transfer case is in neutral it should matter…thoughts?

 

[stumblinhorse]

From the manual. Backward towing and 2 wheels are both no no’s…

I saw a black 392 getting towed in Humble, TX a few minutes ago. Being towed backwards with front tires only on ground by a tow truck. Got me thinking of that’s correct, I guess if transfer case is in neutral it should matter…thoughts?

 

[hardhat]

From the manual. Backward towing and 2 wheels are both no no’s…
View attachment 4956

May be ok since 392 uses clutch packs instead of differential. Reason for extreme wear with one set of wheels on ground would be spider gears in differential spinning all the time. I wouldn’t chance it though. Maybe they will be lucky and front clutch packs at at 0% power transfer when off.
Or maybe he’ll be scratching his head wondering why his transfer case and transmission took a dump at the same time

 

[bkilby]

From the manual. Backward towing and 2 wheels are both no no’s…

Unless they removed the front driveshaft.....

 

[stumblinhorse]

Unless they removed the front driveshaft.....

Hope they did. Or someone is not gonna be happy!

 

[BenLandry]

Hope they did. Or someone is not gonna be happy!

It wasn’t wrecked…I wonder if it was being repoed? License plate was removed

 

[justinB]

OIL LEAK just above the oil filter.

I had a small oil leak just above my oil filter. I initially thought it was run-off from my last oil change but since the leak appeared to be a bit higher than the oil filter I decided to mentioned it to the dealership during my recent 1 year service inspection. There are two threaded plugs that are inserted into the block just above the oil filter. One of the plugs required a decent amount of Teflon tape to seal it back up.

It was mentioned by the service manager that he'd seen three 392s with the same issue. Maybe take a quick peek to ensure you're good.

See pics for further details. In two of the diagrams/pictures I have a pointer 'touching' where the two plugs are located, another diagram has a yellow highlight circling the plugs.

Hope this may help somebody...

~justin

 

[Shortcut]

OIL LEAK just above the oil filter.

I had a small oil leak just above my oil filter. I initially thought it was run-off from my last oil change but since the leak appeared to be a bit higher than the oil filter I decided to mentioned it to the dealership during my recent 1 year service inspection. There are two threaded plugs that are inserted into the block just above the oil filter. One of the plugs required a decent amount of Teflon tape to seal it back up.

It was mentioned by the service manager that he'd seen three 392s with the same issue. Maybe take a quick peek to ensure you're good.

See pics for further details. In two of the diagrams/pictures I have a pointer 'touching' where the two plugs are located, another diagram has a yellow highlight circling the plugs.

Hope this may help somebody...

~justin

Thank you! I just checked mine and it is dry but I will keep an eye on it. I've got about 10,600 miles on it, just turned 1 year old on May 19th.

 

[badidea2.0]

I am having a problem the local dealership cannot solve as of yet. Periodically (more and more frequently now) when accelerating, even mildly, the Jeep will stall like it has hit a rev limiter or speed limiter. I get messages that say Adaptive Cruise Control inoperative, Service shifter, and service Electronic Stability Control. Yellow warning lights stay on. When I turn the engine off and restart, the codes clear but stay stored. I have checked all of the fuses, all are okay. The dealership had me bring it in with the codes still active so they could get a live read, say they are researching, but have not come up with a solution after nearly a couple of weeks. Very frustrating.

Just a guess as I don’t have mine yet to look. But could it be a wiring harness too close to the exhaust. I have heard of this on 392 and diesels. People have weird issues with no resolution and then the wiring harness is found to have some damage and it’s near the exhaust or firewall.

 

[justinB]

Just a guess as I don’t have mine yet to look. But could it be a wiring harness too close to the exhaust. I have heard of this on 392 and diesels. People have weird issues with no resolution and then the wiring harness is found to have some damage and it’s near the exhaust or firewall.

This is feasible. When I first start the Jeep it goes into a limp mode. Not the limp mode like it requires service and will only go 15mph to get you to a mechanic. A limp mode like if I were to 'get on it' prior the engine reaching normal operating temperature, it would be a dog. The PCM shits the transmission in a much higher gear than what would be normal, this to keep the engine RPMs down, obviously staggering the power.

Heat and Electricity are arch enemies. This is why computers have fans, some are even water cooled, and quantum computers are cooled to near absolute zero. This is why lightning never travels the shortest distance, in a straight line to discharge itself. It's all jagged, zig zagging and such, to follow the longer but cooler path in our atmosphere to discharge, it simply follows the path of least resistance - the cooler, more stable & condensed, air molecules, anyways... In the event the wire harness (or any wire) gets too hot, and there may not be any physical damage or a short, that scenario would still present electrical resistance within the wire(s); thus, throw off true sensor readings; therefore, the Jeep would act erratically.

When I first heard/researched this, after one of my front plastic inner fender's melted, I went through the engine bay and zip tied all wires away from any potential heat hazards as best I could, along with anything else that might be affected by heat.

 

[badidea2.0]

This is feasible. When I first start the Jeep it goes into a limp mode. Not the limp mode like it requires service and will only go 15mph to get you to a mechanic. A limp mode like if I were to 'get on it' prior the engine reaching normal operating temperature, it would be a dog. The PCM shits the transmission in a much higher gear than what would be normal, this to keep the engine RPMs down, obviously staggering the power.

Heat and Electricity are arch enemies. This is why computers have fans, some are even water cooled, and quantum computers are cooled to near absolute zero. This is why lightning never travels the shortest distance, in a straight line to discharge itself. It's all jagged, zig zagging and such, to follow the longer but cooler path in our atmosphere to discharge, it simply follows the path of least resistance - the cooler, more stable & condensed, air molecules, anyways... In the event the wire harness (or any wire) gets too hot, and there may not be any physical damage or a short, that scenario would still present electrical resistance within the wire(s); thus, throw off true sensor readings; therefore, the Jeep would act erratically.

When I first heard/researched this, after one of my front plastic inner fender's melted, I went through the engine bay and zip tied all wires away from any potential heat hazards as best I could, along with anything else that might be affected by heat.

Sounds like you have looked into the wire issues. Hopefully the dealer can get it narrowed down.

 

[Centexcpa]

Just a guess as I don’t have mine yet to look. But could it be a wiring harness too close to the exhaust. I have heard of this on 392 and diesels. People have weird issues with no resolution and then the wiring harness is found to have some damage and it’s near the exhaust or firewall.

You were exactly right. On the right side of the engine (from service tech) "found a harness grounding out to the exhaust manifold. Removed the battery tray to access harness about 6 inches before the y291a connector. Found 5 wires shorted, including d303 and d304 going to the sway bar. Repaired all 5 wires and insured harness properly attached to frame, cleared all dtc's". Running great so far.

 

[YukonCornelius]

FCA QA was always mediocre at best... but lately it just seems to plain suck!