My 2021 F450 with 20K miles tossed a CEL while towing 18K 5th a week ago. Forscan read a P20EE code. Into Ford it went ….. was warned the outcome might not be a good one as they have had other trucks in with the same code and can take a hard path to remedy. First path indicated a change of the DEF injector. Changed. Drove 20 miles and guess what ……. Another CEL. Back to Ford and this time indicated action was a new DPF!! BUT they are back ordered until the end of March. Really. The truck only has 20K miles on it. How can the DPF need replacing. Mechanic said the plugged injector likely caused the DPF to fail. Doesn’t sound right to me. I understand there are hundreds waiting for DPF’s and the back order to clear. Why are so many trucks facing this right now? There has to be another cause. Yes, covered under warranty, (it’s an $8-$10K job) but off the road for 6 weeks is what hurts. Thoughts?

 

So glad I've got a 7.3L Godzilla.

 

Lol ……. Considering a KIA right about now.

 

There are enough people out there whose DPF was mysteriously replaced with a straight exhaust pipe that you should be able to find one with less than 200 miles on it. 🤫

 

Yeah, I don't see how a def injector could cause the DPF to clog at 20k. How often was it going into regen?

 

I’m not sure how often regent was running. I used to see a message on my 2011 and 2016 but have never seen a message on the 2021 about regen. Does passive regen still message the driver?

 

It doesn't on my '20 XLT. I have a Bank iDash that I use to monitor the regen remaining percentage, and estimated DPF soot load.

There is a way to program your dash menu to display the regen remaining percentage but you need to do so using the Forscan computer program and an ODBII interface and cable. Also, using the same setup you can enable the manual regenerations menu option, and I'm in the process of getting that enabled for mine currently.

 

DEF injector should be after the DPF and have nothing to do with regen or the DPF. DEF is injected before the catalyst.

 

I would have to look again, but on the pickups the DEF injector may be before the DPF.

 

DEF injectors spray DEF into the SCR catalyst, and have nothing to do with the DPF. A plugged one would only cause NOX levels to shoot up, but again, would have no impact on the DPF. If it was just the opposite and dumped DEF into the exhaust, then it is possible to have wet DEF accumulate in the DPF which will clog it. The injection is just the right amount to turn it to steam to coat the catalyst so it converts the NOX to CO2. You would go through a LOT of DEF in a short amount of time if that were the cause. Do you recall how quickly the DEF went down during your tow?

A DPF is a pipe with tiny tubes running from end to end to catch particulates from the exhaust, what you normally see as black smoke. When it goes into regen, raw fuel is dumped into the exhaust stroke and pumped to the DPF where it raises the temps inside to burn off the soot. There are sensors before and after it to measure the pressure differential to let the computers know how much soot is accumulating.





It is rather simple in function, but rather easy to foul up too if the computer and sensors dont jive, or the raw fuel dumps during regen are not reaching full regen temps. Partial regens could also lead to a fouled DPF by not getting a complete 100% cleaned out DPF.

What did the code say it was when you got the CEL? Did they try to run a manual full regen to purge the DPF?

Sounded more like they were tossing parts it it instead of doing a full diagnostics on it.

Going into a dealer service with knowledge of HOW the system works, even if just the basics as I laid out can go a long way towards actually getting the correct diagnostics done and not just swap out parts they thing are the problem. Thats how this sounds to me.

 

As was posted above, no message for passive or active regen is given and to monitor it would require one of the methods mentioned.

The reason I asked about the regen frequency is because it is my understanding that prior to the use of the SCR/DEF, regens were more frequent. NOx reduction was handled more from the EGR and therefore more soot. So I was thinking, DEF injector goes bad, does that cause more EGR activity, more soot and more frequent regens. I still don't see how it would clog the DPF so fast. I wonder what effect a DEF injector that pumps too much into the exhaust has? Just noticed that acdii may have answered that.."If it was just the opposite and dumped DEF into the exhaust, then it is possible to have wet DEF accumulate in the DPF which will clog it"

 

Being that the DPF is a ceramic that is porous to catch the particles, if the ceramic gets wet it can easily clog up, and then when subjected to high temps, it could possibly harden the soot accumulated to where it no long burns off. Would the chemicals in the DEF bind with the soot and any other chemicals left over after combustion turn it into a glaze?

 

P20EE is a DEF code, has nothing to do with the DPF.
Many times just a NOx sensor, possibly a bad catalyst.

 

Understood. I do have FORScan but have not added the % etc to the dash. Will be for sure when fixed up.

 

in my case the first error code P20EE pointed to the DEF Injector ……. It was clogged with minimal output. The injector was replaced and code cleared.