2016 DD15 - 4364 FM18 and 5246 FMI0

Hi all,

I have a 2016 DD15 with 693k miles. Last night she lit up like a Christmas tree; displaying the following two codes and message:

SPN 4364 FMI 18
SPN5246 FMI 0
engine derage 25%
DEF Quality poor, Check DEF

Red Stop Engine light Was on as well, DEF light was blinking but couldn’t force regen.

truck limited me to 5mph

I cleaned out the DEF injector, which had DEF build up, and placed it back, still didn’t change. Called Loves over to me, and the technician said everything looked good in the computer but he couldn't clear the codes. I saw a truck shops near me and started heading over, but as I was driving 5 mph, I started going downhill and got to about 40 mph, at which point there was a loud noise underneath the truck and the lights all disappeared, and the truck began to gain speed. I’m on my way to delivery right now, late but thankful that I didn’t have to get towed.

Anyone have any idea what it could be?

3 months ago I took it to Freightliner because it kept forcing me to regen and I had the check engine lights on, they found large building up in the mixing chamber and performed a DEF awning. Set me back $3k. The truck ran for a bit but then started giving me the check engine lights and derating the truck. I thought maybe it’s the DPF filters, so At about 685k I changed the two DPF filters because the truck kept having to regen, about 3 weeks ago. It worked just fine the past two weeks.

this time, I’m driving through VA with about 40k lbs in the trailer, and the truck was fighting up the hills before it sedated and all the lights came on.

Any ideas as to what the problem could be?

 

Like Antinomian said, when they installed the DEF awning they had to remove the DPF filters and look at the DOC as well. When I replaced the DPF filters myself two months later (the truck sat for about a month after they installed the DEF awning), the DOC filters looked like they were in good condition (pictures attached below for reference).

 

I changed the DPF filters myself, you can look at the DOCs in the images I'm attaching below. I ended up replacing the DEF Metering unit (AKA DEF doser, DEF injector) on the side of my Onebox as well, and replaced my DEF filter with a new one. The old one (pictures of old DEF filter attached) looked like absolute crap, which makes me believe the previous owner never serviced the DEF Filter.

Attached you can see my old DEF metering unit/doser and the port on the one box with DEF leakage.