My 2020 Jeep Rubicon “JLUR” could have killed me and my family this weekend.

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Fsttanks

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Tony, et. al.,

Sorry I'm so late to this conversation. While I am in no way currently associated with FCA or the automotive industry any longer, I was a Software Engineer with Chrysler helping develop their Powertrain Control systems for their 2000 through 2006 Model Year Small Car, Large Car and Jeep Truck programs.
The lure of living in Colorado pulled me away from the metro-Detroit area rat-race.

Everything electronic back then was either already Controller Area Network (CAN) connected or moving that way. So fast forward to today, I would suspect that every electronic component requiring some input or output control is indeed connected to the CAN bus.

For the uninitiated the CAN mechanism is indeed a 'bus'. That means that many 'nodes' can be physically connected together in a common link. This link is made up of generally a twisted pair of wires. One being marked plus + the other being marked minus -. This provides an electrical differentiated signal to be used as the physical link. It is the difference in voltage (rather than the voltage level) that is used to define the actual signalling.

The CAN protocol itself is rather sophisticated and was designed and used as a very reliable (short distance) communication control system. Each and every node within this two wire 'bus' has a unique CAN address that has a built-in priority scheme. Any node can communicate with any other node via a seven byte message (frame). Each frame consists of the source and destination's node address as well as the message payload itself. Any node can originate a message at any time but only the message with the highest priority address will win bus arbitration at any particular instant.

In practice, the communication strategy is typically implemented with a high-priority source control module that manages lower-priority peripheral components. Each controller typically has their own separate bus to talk within their own little sphere of responsible components. The door sensors are monitored by the body controller, the volume knob is monitored by the radio, the O2 sensors are monitored by the engine controller etc. Then the top level controllers are then connected to each other by yet another separate bus.

However, in practice there are many factors trying to thrift away cost. Each and every little piece of anything costs money to be installed. So there is always great pressure to eliminate stuff like 'wires'. Well it doesn't seem like much, every penny saved on volume production generates potentially millions, or more, in savings.

A common practice is to replace the minus (-) wire with the common vehicle frame (ground). Thus you now only need a single wire rather than the more common (and more expensive) twisted pair. However, in so doing the twisted pair reduces, even eliminates, cross induced noise from the electrical signaling, whereas the single wire solution will not. So like everything in nature there are tradeoffs. In this case cost vs noise immunity in regards to reliable message exchange.

Looking at the JL's CAN wiring diagram, it doesn't appear that the single wire approach has been implemented. But this is just a diagram. In practice, some sensors may certainly be. However for the backbone bus, the one connecting all the major controllers together, these should be high quality twisted pair links.

So in order to have so many component faults, this indicates a fundamental signaling failure between the top-level controllers. It very well maybe a high-impedence short that is clobbering the CAN addressing mechanism.

The only good way to troubleshoot this is by isolation. You need to remove each node one at a time, starting at the highest priority components and work your way down. If I was the engineer assigned to go puzzle this problem out, I would be removing the in-vehicle harnesses and bypassing them with an isolated counterpart. Then revaluating the condition of the overall system. Continuing to do this potentially with each and every harness throughout the entire vehicle. But this troubleshooting would be way beyond the skill of an ordinary dealership tech. Not impossible, but access to the harnesses and protocal analyzers would make it rather difficult if not outright prohibitive. Unless you found a dealership owner with very deep pockets willing to Fix an FCA problem. Isn't ever going to happen.

I would further suspect that FCA would highly value your Jeep in order to really (scientifically) understand what went wrong on this particular vehicle.

If they offer to buy it back, please let them. While every problem is solvable, some things are better solved with the bigger picture in mind. Whether this was a manufacturing flaw or a design defect it will benefit all of us to have them look at this vehicle from an engineering rather than dealership perspective. Having the NHTSA involved certainly makes your Jeep more valuable to them than to you.

If I was on the team assigned to evaluate this, my recommendation would be to give you a top-of-the-line Rubicon (or whatever it is you want) in order to do an absolutely sound failure analysis on this particular unit.

Hang in there. Jeep's are certainly more reliable than whatever happened here. I suspect a manufacturing flaw or a pinched or shorted wire to something other than a hard ground. And I suspect it's on the inter-connected controller harness which is likely the hardest to replace. Hence why no one is willing to replace it.

Again I can be all wet behind the ears. But I don't believe so.

Good luck, thank you for being so remarkably understanding and patient. Also, I'd be the first one to contribute to a Go-Fund me page if FCA doesn't own up and do the right thing.

Jeep on Tony. You are certainly one of the good guys. You have all my respect.

Jay
Thank you for your time and sharing your knowledge IT IS greatly appropriated!!!

I spoke with the dealership late on 12/11 and they have not been able to duplicate the last issues, but they know IT happened because of the OBD information. They requested my permission to let the tech do some “extend driving” with the Jeep in hopes the issue will occur. I have given them permission with a strong warning.

The tech will begin the “test drives” on 12/14.
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_olllllllo_

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Glad you are all safe. I do hope that Jeep resolves the issue and it is a permanent solution and the vehicle provides total happiness in the future. As others have said the march towards more and more electrical systems invites issues that can't really be resolved by those without sophisticated analysis systems and the codes to access the deeper reaches of software. Just wait when in 10 years a large percentage of vehicles are Battery Electric Vehicles (BEVs) and everything is electric and fly-by-wire, with limited or no mechanical interfaces.
 

JeepDrvr2018

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Don't know if anyone remembers, but about 10-15 years ago, automakers were talking about a 24V electrical system, it got shelved because of the costs involved, and sort of figured IC's and better communications between components lower power requirements made up that difference. Computers are tool, albeit just one tool in the box, they cannot do everything, nor should they. This incident has made me maybe take step back from Gladiator purchase since they are related, and I don't want to lose everything going down some of the hills we have here in these mountains. But this also has cemented me on getting the 6-speed because you cannot put a computer on a manual transmission, and at least I can get it into a lower gear to slow down.
 

NorCA

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Day 27...

I spent the better part of the day driving up to the remote dealership with the hope of obtaining more information on the catastrophic electrical failure that happened on 11/17/2020 near this remote dealership. My 2019 Hellayella JLUR was found shoved to the back of the lot.

I asked the service advisor assigned to my JLUR if he could provide me with a list of what has been performed to-date; NO, not until it is closed out. I asked the service advisor if he could provide me with a list of current fault codes; NO. I asked the service advisor if he could tell me what the service technician has reviewed (e.g., fuses/relays); NO. I asked if I could talk with the service technician; NO.

The service advisor assigned to my JLUR would only give me lip service. He indicated they have been providing information back to STAR engineers/technicians and they have been advising/directing which components to test/replace. The service advisor indicated there is no new date for the inbound computer module (he could/would not tell me which module, only that it was the second one) from the expected 12/23/2020 date. Additional lip service included attempted reassurances that the service technicians at this dealership were "bright" (perhaps they are skilled, but none of the advisors or technicians were wearing masks).

I do not know if Jeep/FCA prioritize backline technical resources and/or constrained parts orders to dealerships based on their size, location, volume of sales or some other metric. I have ZERO CONFIDENCE the inbound module will resolve all outstanding faults. I also do not know if Jeep/FCA tows/relocates a vehicle to a dealership that backline engineers have a better working relationship with, a dealership that has better diagnostic equipment or a dealership that receives parts faster.

HELLO @JeepCares ... I WANT MY JLUR.
 
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Joe98

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What is a "The almost $600 “smart” alternator aka “generator/inverter” ".

Does it come standard with our Jeeps?
 

jeepoch

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@NorCA,

Michael you have to reference their forum username JeepCares in order for them to see your post. Maybe they'll see this and puzzle it out.

@JeepCares please refer to post #214 in this thread.

Jay
 
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Fsttanks

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What is a "The almost $600 “smart” alternator aka “generator/inverter” ".

Does it come standard with our Jeeps?
According to Jeep, there is no “alternator” used on the JL. 3.6 engines. It is a “generator/inverter” which is more then a simple “alternator”. Only stating what I was told by the dealership.
 
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Fsttanks

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Day 27...

I spent the better part of the day driving up to the remote dealership with the hope of obtaining more information on the catastrophic electrical failure that happened on 11/17/2020 near this remote dealership. My 2019 Hellayella JLUR was found shoved to the back of the lot.

I asked the service advisor assigned to my JLUR if he could provide me with a list of what has been performed to-date; NO, not until it is closed out. I asked the service advisor if he could provide me with a list of current fault codes; NO. I asked the service advisor if he could tell me what the service technician has reviewed (e.g., fuses/relays); NO. I asked if I could talk with the service technician; NO.

The service advisor assigned to my JLUR would only give me lip service. He indicated they have been providing information back to STAR engineers/technicians and they have been advising/directing which components to test/replace. The service advisor indicated there is no new date for the inbound computer module (he could/would not tell me which module, only that it was the second one) from the expected 12/23/2020 date. Additional lip service included attempted reassurances that the service technicians at this dealership were "bright" (perhaps they are skilled, but none of the advisors or technicians were wearing masks).

I do not know if Jeep/FCA prioritize backline technical resources and/or constrained parts orders to dealerships based on their size, location, volume of sales or some other metric. I have ZERO CONFIDENCE the inbound module will resolve all outstanding faults. I also do not know if Jeep/FCA tows/relocates a vehicle to a dealership that backline engineers have a better working relationship with, a dealership that has better diagnostic equipment or a dealership that receives parts faster.

HELLO JEEP CARES... I WANT MY JLUR.
Does not surprise me to hear this. Jeep has no idea what is going on or a way to fix it at the dealership level.

I suspect you and me both will be hitting the 30+day mark in our dealings with Jeep and both our dealerships know it, so why waist their time trying fixes. Soon the choices for Jeep will become limited and straight forward.
 

neil

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According to Jeep, there is no “alternator” used on the JL. 3.6 engines. It is a “generator/inverter” which is more then a simple “alternator”. Only stating what I was told by the dealership.
Depends on the jeep w the 3.6, some have a regular alternator or 240a (manuals).
 
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Fsttanks

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Depends on the jeep w the 3.6, some have a regular alternator or 240a (manuals).
Like I mentioned in my post thats what the dealership explained it as, a “generator/inverter” and that all the JL 3.6 engine use it. I am not making that claim just passing on what I was told. Wouldn’t surprise me if it was BS. To me I could care less what Jeep calls it. It’s still just an alternator, with fancy functions that has more to go wrong.
 

NorCA

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Does not surprise me to hear this. Jeep has no idea what is going on or a way to fix it at the dealership level.

I suspect you and me both will be hitting the 30+day mark in our dealings with Jeep and both our dealerships know it, so why waist their time trying fixes. Soon the choices for Jeep will become limited and straight forward.
The sad part is that the remote dealership (38°22'58.0"N 121°56'22.2"W - avoid it) that has my JLUR is not my regular dealership, it's just the closest dealership to where the JLUR went haywire.
 

JeepCares

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Hi @jeepoch,

Thank you for tagging us.

@NorCA,

We understand how frustrated you must be! Please send our team a private message with your VIN so that we can look into this further.

Darlene
Jeep Cares
 

oldcjguy

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NASA landed men on the moon with " less computer power" then we have in our cell phones now.
And half a century later jeep is still fuckin around half baked bad engineering .
In fairness each NASA vehicle was scrapped and useless after a single trip.
And they spent most of their trip coasting without their engine running either :)

Sorry, couldn't resist... LOL
 

JEEPIDON

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In fairness each NASA vehicle was scrapped and useless after a single trip.
And they spent most of their trip coasting without their engine running either :)

Sorry, couldn't resist... LOL
They also didn't use microsoft that everyone in the world can hack!
 
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