I have a bone stock 2011 F350 with 125,000mi. It has recently been giving a P207F code with a warning for a 50mph derate.

A month ago it thrown a code for the nox sensor heater, it was replaced with a genuine sensor and I also cleared the nox charts when I changed the sensor. Less than 500 miles on the new sensor and it’s now giving a P207F. When I clear it immediately comes back with the same speed limit message and code.

What else should I be looking for? I’ve done a lot of diagnostics and everything in the after treatment checks out. P207F on a 6.7 is a very vague code and I’m now needing help diagnosing this issue.

 

Have you made sure that all the pcm updates have been applied.

There are a few cases of folks having problems that went away with the pcm updates.

 

The only other info I can offer

if def is not being pumped into scr your nox readings would be super high….there are various components in def system that could fail

me personally would try one of the new def “crystal” dissolver products. It’s basically a special type of dish washing liquid. I have seen it sold at autozone and oriely’s

you can test to see if the nox sensor circuit is working correctly by removing it from the rear tail pipe while leaving it connected “tie it down somewhere or use one of those spark plug anti fowl socket inserts to test…if the circuit is working correctly there would be no more nox related codes . Don’t forget to put the. Ox sensor back into the hole after you test.

 

To expand on what Fritz is saying:



https://www.expertswrite.net/article...07f-diagnosis/


https://www.forddoctorsdts.com/forums/topic/6070-p207f/

https://www.forddoctorsdts.com/forums/topic/6556-p207f/

From this link : https://www.thedieselstop.com/thread...e-mode.658760/



Good luck.... Plenty of good links to get you started.. I searched on Bing with "6.7 powerstroke p207f"

 

It is most likely a bad SCR.

Absent a new air filter, a EGR valve check to ensure it is within proper specs, def concentration check with at least 31% to 33% concentration.

Unfortune if a bad scr the dpf gets replaced too as it is one unit. Cost is gonna be around $3500 labor?