DEF Limp mode, do I need a new PCM?

Hey guys,

I have a 2013 Ram 4500 with the 6.7L.

Here's what happened. I had my CEL on for a few months, so while the truck was at the dealer for a coolant leak repair, I asked them if they could scan the truck and see what the light was about. They said I needed to do a flash update, which I was okay with. However, somewhere along the process, they said they tried doing it, but something wasn't working right so when they asked Chrysler, Chrysler said I have to replace my PCM. There's no other way to get rid of that light.

I didn't want to pay $3k for parts and labor for the light to go off, so I took the truck home without doing anything.

When I got the truck, the truck EVIC said the message of "Service DEF System, see dealer" (or something like that). I called the dealer to see if that could be taken care of, but they said they would have to replace the PCM for that. They also said that I can drive it around with that on, without a problem.

A few days later, the truck goes into limp mode, and am counting down the miles till I go 5mph.

Do I have any other options other than to replace the PCM at the dealer?

Thanks in advance, guys!

Interesting, do you know the original fault code? why they wanted to flash the ecm? I know chrysler likes to shift the blame on to the dealer when flashes go wrong. ( the dealer has no choice but to make the customer pay for it or eat it) not saying this is the case for sure, but if it is, I would be contacting Chrysler for some help.
Again don't get in the dealers face about it, but if it is the result of a flash gone wrong I would call Chrysler assist number and go *******.
Remember, independent dealers don't warranty your truck, they only work on it and get reimbursed by FCA. They cant afford to work on your truck for free, FCA needs to step up to the plate if this is the issue

Yoda, thanks for the reply!

I do not know the original code. I tried the code checking sequence a few times with the dash indicator, but it always said there were no codes.

I hear you on the Chrysler/Dealer thing. I guess I will call them up on Monday to see what they say.

Thanks for the advice!

How many miles are on your truck? Emissions warranty is 5yr/80k and powertrain is 5yr/100k.

There is something tripping the PCM to show the CEL. I would start looking at the NOX sensor on the SCR, and then the doser, and lastly the catalyst itself. If you can, siphon out as much DEF as you can and fill it with fresh stuff. Then when you take it to the dealer for service they won't be able to pin you with the bill for the famous "DEF is degraded" line. Don't get bullied or pushed around.

After you put the fresh stuff in drive it a week or so and the CEL just might go away on it's own. I have never heard of a PCM legitimately going out unless there was actual tampering or a lightning strike lol. I seriously doubt that is what it is.

Just to clarifie, if the flash damaged the ECM , FCA should step up, if the flash caused the ECM to recognize the problem, sorry you are out the, $ in my opinion

Hey JRG18, I have 150K on the truck.

Before I look into those things you mentioned, since I'm already in limp mode, am I already stuck? Meaning, no matter what I do now, is there any way to turn off that countdown?

@Yoda - I agree.

Burli34 said:

Hey JRG18, I have 150K on the truck.

Before I look into those things you mentioned, since I'm already in limp mode, am I already stuck? Meaning, no matter what I do now, is there any way to turn off that countdown?

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Again, don't take it as gospel, but lurking around cumminsforum I have seen a handful of guys say that even when the countdown gets to 0 the truck drives fine. Others have bought a cheap OBD-II reader from harbor freight or somewhere and were able to clear the code themselves, or at least read what is causing the CEL. I didn't see anywhere in your OP of what the actual code was tripping the system. If the PCM were all messed up would it even be drivable? When I messed up my PCM trying to flash in a tune on my last truck the it wouldn't even start anymore and I got codes galore. Once I was able to flash the stock tune back in the truck started right up and I was eventually able to tune it again.

Also, as a caveat, I had taken that truck to the dealer. I had them run their tests and I got the word my PCM was fried and needed replaced. The cost was like $1800. I was told after asking that they aren't able to flash a PCM with a stock map, which is crap btw cause how would they do it with a new one, and they kept saying the PCM was completely fried so it wouldn't take a new flash anyway. It sat on the lot for a day or so. I was able to get the stock map from Bullydog, went there and flashed it in, and waved at the service techs as I drove off the lot.

Yea I agree. I actually tried clearing the code with an AutoEnginuity scanner thing, but that didn't do anything. I didn't get the Chrysler package with it, but still, I thought it would have read something.

Hmm, so is there a way for me to check the output of the NOX sensor? And can you explain what the "doser" is?

Oh that's very interesting! I can definitely try that! Just do a stock map flash with a Bully tuner? I don't have one, but I can get one!

Burli34 said:

Yea I agree. I actually tried clearing the code with an AutoEnginuity scanner thing, but that didn't do anything. I didn't get the Chrysler package with it, but still, I thought it would have read something.

Hmm, so is there a way for me to check the output of the NOX sensor? And can you explain what the "doser" is?

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The doser could also be called the DEF injector. It sits on the engine side of the SCR and "doses" DEF in accordance with what the NOX sensor downstream tells it to.

It's possible if you didn't get the "chrysler package" that it wouldn't read it. Find someone with another scanner or source another to be sure.

Ohh okay, got it! Thanks JRG18!

I will look into finding someone with the scanner.

Burli34 said:

Oh that's very interesting! I can definitely try that! Just do a stock map flash with a Bully tuner? I don't have one, but I can get one!

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With a tuner it is going to store your stock map in the tuner and flash in the tune you selected. If you get a new bullydog tuner it will be blank or empty. I had to explain that when trying to flash the tune in it froze and messed everything up. I was sent a stock map from them in an email. I downloaded it to the tuner and plugged it in. It did it's magic and I was good to go. You could try contacting them and letting giving them the same story and hopefully they'll send you the map but a regular ole tuner isn't going to help any without that file.

Definitely going to follow this as I'm curious as to what it turns out to be.

Ohh okay, would they just email that tune to anyone who asks?

P20EE code - Dodge Cummins Diesel Forum

I was reading through this earlier today coincidentally and if you read through the first few pages you'll see how prevalent your problem was on the 13 and early 14 trucks. Might want to chime in there and see if anyone there has any better insight. Good luck with your truck.

Wow, I just read all of that... sounds like this is going to be a project! =)

Hey guys, so here's what happened.

I took it to another dealer, and they told me that when I had replaced my SCR a few months ago, that dealer never adjusted the parameters on the sensor to make it compatible with the new SCR. Therefore, these guys just adjusted the parameters on the sensor to match the new SCR, did a flash update, and $119 later, I was good to go! These guys saved me $3,000! If you're ever in Texas near Austin, it's a dealer in Taylor, TX. Good guy named Cliff that handled everything for me. He has a reputation of doing good, honest work.

Also, thank you to all of YOU guys for your help. Really, I might have ended up convinced that I had no other alternative if it wasn't for you guys. So yea, thanks so much!