Yesterday while driving to work, I noticed a CEL illuminate on the dash and a few minutes later the "in 50 miles, speed will be limited to 50 mph" message came on. I continued driving to work for about another 10 miles, shut the truck off, and went inside. 10 hours later, I go back to truck and start it and message was still there as was CEL however I had enough mileage to get to my hometown dealer so I decided to go for it and drive. About 2 miles later, I get on the interstate and I get a "cleaning exhaust filter" message and the truck goes into a normal regen. At about 25 miles to 50 mph, the fault message disappears and I was able to continue on to the dealership however the CEL was still on.

When I pulled in to the dealership, the service advisor pulled the dreaded P207F code with his mini scanner and cleared it. I know what that code is, however Im curious as to why it would have triggered on my truck and why the exhaust fluid fault went away on its own. I know it will possibly come back, I keep driving it and its been normal. Is it possible this was a one time error message or will it likely reappear soon. I do not want to delete yet as I am still under warranty however I have a long trip coming up in a couple weeks so I would hate for this to happen while I am on the road.

I also thought I would add that I filled up my DEF over the weekend (2.5 - 3 gallons) and my DEF fluid level is saying OK. Ive read somewhere that adding DEF before you really need it can cause the sensors to go haywire. But like I said, the main thing that confused me was why the DEF Fault message went away on its own?

I also changed air filter and fuel filters last weekend.

Any help on this would be great, especially before a long road trip. I want to drive but I have the option to fly as plane tix are cheap but i am not fancying the idea of renting a car...


Thank You

 

I just had the def heater replaced on mine, don't remember the code. Was under warranty due to high failure though. It would trip the cel and reduce power, but not that much. I drove it for six months like that before I had it replaced, don't really need the heater down here.

 

As long as its not below 12 F and the def tank isn't frozen, a def tank heater failure won't result in limp mode, as the DEF injection event can still occur.

However, in OP's case, a P207F indicates that NOx emissions *were* outside of the allowable range. This will result in limp mode and won't go away if the high NOx output does persist. Maybe it was a fluke in his case, or maybe its a problem on the verge of getting worse. Could be due to failing def injection, def pump, plugged EGR valve, bad NOx sensor, etc.