So driving to breakfast today in my 21’ 350, get about 5 miles from home and get def fault message that says speed reduced to 50 mph in 50 miles, check engine light appears as well. We get to our breakfast spot and I park shut it down wait a minute and restart with the same results. Truck has 14,200 miles and is meticulously maintained, had only motorcraft DEF fluid and literally just chand the fuel filters and oil within last 100 miles, all ford filters and T6 5w-40.

so we eat and leave, drive 3-4 miles to the highway, I have auto regen disabled through Forscan, DPF was at 45%. I get on highway and turn on auto regen and truck does it’s thing and is down to 0% in about 10 minutes, running fine can’t notice a thing, now before I got in the highway the DEF symbol disappeared but CEL is still on, solid. I get home and grab my laptop and hook up forscan find codes ( P2201-C) and clear both. Take it for a ride, drive 20 miles and all is good….. a little stumped here, leaving for Florida in 2 weeks towing the 5er. Problem is, I don’t drive the truck that much as I have a work vehicle….

I filled the DEF fluid lastnight to the rim, with Motorcraft fluid….

 

Mine does the same thing and I want to say it does it during the colder months 2-3 times/year and I just drive it and the DEF message goes away first and then the CEL light later.

 

Interesting, I am wondering if its because the DEF was filled to the brim? Or maybe its a bad NOX sensor....I dunno, gonna try and drive the **** out of it this week and see if it returns.

 

hopefully you are not in freezing temps with it being overfull.

I would just drive it. If it ever comes on again while down in florida I would then take it in for them to look at it. Doubt anything is wrong.

Plan on switch the def guage in place of the turbo boost gauge for the tow. Mine eats the def pretty good when towing and I just fill up def at the pump since truck stops all have it.

As long as the def station is clean, I will take one of paper towels and wipe the nozzle before use. No issues.

 

Well it hasnt gotten that cold here in SE. Massachusets yet, I plan to put some miles on the truck this week to make sure its not going to reappear before we leave for FL. If it does happen again im not sure i would be able to get inot the dealer before we leave? I cleared the codes so no sense in bringing it in unleess it happens again.


On a side note, not sure this has anything to do with it, but I do have auto regen option disabled/enabled and have had it turned off for most of the summer. Seeing as how we have been towing a decent ammount this summer and the truck has been passively cleaning DPF. I had roughly 3,200 miles since it last had an active regen, hence the reason I let it do a regen yesterday. Again could have nothing to do with it....

 

I think you will be fine for the trip.

Temps have been pretty nice haven't they.

I turned the A/C back on at the house.

 

I am hoping so, ill have my laptop with me anyway so I can check codes if needed.

Yes, was a very nice weekend here in the NE!! Wont be like this much longer.

 

I had a DEF system fault recently that required a visit to the dealer. The truck thought the DEF injector was stuck shut. Limp mode was pending and since I was out camping with a trailer, the issue needed to be addressed ASAP. It was covered even though I was out of the 3/36 warranty.

 

I am guessing it gave you a DEF Fault message?

 

Just the check engine light. All my electronics were packed deep in the truck. Otherwise I could have dug it out and grabbed the code myself. The dealer was conveniently on my route and they pulled the code right away and took care of it the next morning.

 

Just curious but why would you
.

 

well regents aren’t exactly good for the engine, why wouldn’t I? Pretty sure no harm is done and it’s completely controllable.

 

I thought it was bad for the regen not to occur on schedule?
With my tractor when it regens I let go through the cycle. When my warranty is over and I can delete that crap I will.

 

The trucks regen not just on filter status but also every some number of miles. My tractor regens too, but only when needed according to the filter state. The 6.7 left to its own devices will regen every so often whether the filter needs it or not. I recently learned that 100% full on the dash is really 33% full. So regenning every X miles "just because" is pretty wasteful. Presumably it's programmed this way to work around people who want to fool a regen algorithm based solely on how full the filter is by manipulating the pressure sensors.

 

I hadn’t had a active region in 3200 miles having the auto region box unchecked. Considering I don’t drive the truck all the time and it is used a fair amount for towing our fifth wheel and the trips we did this summer at passively regend for the last 3200 miles. I probably could have gotten away with not doing an active region this past weekend however I thought maybe that had something to do with the DEF fault?