Another PCM Failure Post...

[Backcountry ADV]

2021 Mojave Build and only 6k miles. Dropped it off for a set of Rigid Lights (Pillar Mounted) and a re-gear to 5.13's after some input from you fellas (many thanks by the way). Performance shop calls and said next day Jeep wouldn't move. It would start but with flashing lights all over the dash and was locked in park (shifter wouldn't move). After some trouble shooting they discovered a blown fuse that was preventing the shifter. Wouldn't run correctly so they retraced all the wiring, etc and finally decided to send it to the local dealership for a possible PCM failure. Dealership has it a few days and decided to order a replacement PCM. New PCM starts and runs but has a weird code that is only showing on the Data Link Side (not the Comms side that runs through the vehicle and other sensors). They decide to overnight another new PCM and after bench flashing they install with the same problems. Vehicle is stated to start and run ok but with the check engine light per the weird code.

No other problems other than this new problem code. Plug in old PCM and no code. Plug in either new PCM, weird code shows up.

Per my request, they verified part numbers and firmware versions on both new and original PCM.

I'm absolutely open to suggestions, input, insight, or other ideas to try to help them trouble shoot this issue.

They are asking us to unplug the Rockslide Engineering Steps and Rigid Lights that were installed as they deem they could potentially be an issue. I'm not sure this is proper logic as they were installed at nearly Zero miles along with the Clayton 3.5" Overland Plus kit and Fabfours Bumper/Winch with no issues since new. Now at nearly 7k miles, they're trying to blame anything aftermarket on the PCM issue. I asked if we pulled those items (electrically removed them at source of power) and they still got the same codes/issues with the check engine lights and weird trouble code what their next step would be and they looked at me like I was from Mars. They literally have no clue of what to do next if I remove their only excuse of it being related to the aftermarket upgrades.

Let's here your stories, inputs, etc and I'll update once we eventually solve it.

P.S. What's the likely hood of a bad batch of PCM's? They have a hard time believing two back to back new PCM's would have problems. I think I read another post from a while back on another 21 that had a PCM failure that went through a few PCM's only to find out the part number or something had been updated but wasn't in the manuals/books yet under the VIN. Thanks in Advance for any insight!

Cheers!

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[Willys2Gladiator]

So it was fine before it went into the performance shop. Then after installation of some electrical accessories you have electrical issues?
Really, I'd say the shop shorted something.

Hope you get it sorted out.

 

[Backcountry ADV]

So it was fine before it went into the performance shop. Then after installation of some electrical accessories you have electrical issues?
Really, I'd say the shop shorted something.

Hope you get it sorted out.

They only added another set of Rigid lights on the same source the previous set was installed over 6k miles ago. Nothing new.

what’s weird is the Trouble code that’s only on the new PCM’s.

 

[Backcountry ADV]

Quick update. Jeep dealership now claims after getting feedback from ServiceLink & Corporate it’s a known problem with bad PCM’s & an error code. Even better, they have zero support, zero solutions, & zero timelines.

what’s the best route to filing a consumer complaint or customer service issue to get some feedback and urgency??

 

[Mr._Bill]

Start with Jeep Cares, emailing Corporate, and check into the Lemon Laws for your state.

 

[DAVECS1]

What's the weird service code? I am highly skeptical. There is not a known batch of failed ECMs or known ECM problems. There is definitely lack of documentation for changes and available service information. These are made by continental and have pretty impressive specs for survival.

My guess is something got set wrong when the new ecms where installed.

What are the trouble codes on the original ECM?

 

[NC_Overland]

Quick update. Jeep dealership now claims after getting feedback from ServiceLink & Corporate it’s a known problem with bad PCM’s & an error code. Even better, they have zero support, zero solutions, & zero timelines.

what’s the best route to filing a consumer complaint or customer service issue to get some feedback and urgency??

I’d feel fortunate that they are fixing it. It worked fine before it went to the shop who installed electrical accessories. It would be so easy for them to not cover it.

 

[Backcountry ADV]

What's the weird service code? I am highly skeptical. There is not a known batch of failed ECMs or known ECM problems. There is definitely lack of documentation for changes and available service information. These are made by continental and have pretty impressive specs for survival.

My guess is something got set wrong when the new ecms where installed.

What are the trouble codes on the original ECM?

PCM code: P0600 Pending / Serial Communication Link.
It’s only on the 2 New PCM’s but not on the Original. Additionally I asked them to verify all versions of the Bench Flash Software we’re the same & purportedly it is which makes me believe it’s an issue with the New PCM’s or their installation of them.

 

[Backcountry ADV]

I’d feel fortunate that they are fixing it. It worked fine before it went to the shop who installed electrical accessories. It would be so easy for them to not cover it.

I’d tend to agree but it was electrical then why the new trouble code only on the 2 new PCM’s? If it were something fried it would be an issue with the OEM not the 2 new ones in my opinion.
PCM code: P0600 Pending / Serial Communication Link.
It’s only on the 2 New PCM’s but not on the Original. Additionally I asked them to verify all versions of the Bench Flash Software we’re the same & purportedly it is which makes me believe it’s an issue with the New PCM’s or their installation of them.

 

[NC_Overland]

Additionally, MMWA Act covers the dealer/manufacture from denying or limiting factory warranty for usage of non OEM products unless it’s proven to be the only cause.

MMWAhttps://www.autocare.org/government-relations/current-issues/Magnuson-Moss-Warranty-Act

Oh lawd, I’m going to pretend you didn’t post that. You have no idea what a can of worms that opens posting that on an internet automotive forum.

 

[DAVECS1]

PCM code: P0600 Pending / Serial Communication Link.
It’s only on the 2 New PCM’s but not on the Original. Additionally I asked them to verify all versions of the Bench Flash Software we’re the same & purportedly it is which makes me believe it’s an issue with the New PCM’s or their installation of them.

So all the ecms on the data link have a rolling security code like your garage door. They all have to be in the correct sequence in order to communicate. There is a service procedure that writes all the ECMs at one resetting and syncing that code. The other ECMs are just fine the truck just needs to have the calibration loaded correctly.

 

[Backcountry ADV]

So all the ecms on the data link have a rolling security code like your garage door. They all have to be in the correct sequence in order to communicate. There is a service procedure that writes all the ECMs at one resetting and syncing that code. The other ECMs are just fine the truck just needs to have the calibration loaded correctly.

i would love some more insight or information as to how to relay what’s needed to the dealership. Feel free to post up or DM me directly. I’d just like to get it resolved.

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