2017 6.7
so over the weekend i filled my DEF (it was half before i filled up, not empty). yesterday on the way home an alert chime came up and said def

speed limit to 55 in 40 miles. i have 30 miles to get home so i got home and turned truck off and later went out to go somewhere and no warning light.
this am the alert came up again (DEF fault speed limited to 55 in 46 miles.).

what is this caused by and what to look for to correct?

 

Looks like your truck doesn’t like low tire pressure and a full DEF Tank.

Sounds like a faulty sensor. I only saw this warning on my previous PSD once but I was truly low on DEF.

 

yeah i gotta get into forscan to change that low tire warning-
hmmm now to search for this sensor location and such..... i know a month or 3 ago the warning came up for the 1st time but i was truly out of DEF then (almost out)

 

when you fill your def, you can run a def recalabration proceesdure in forscan.

 

ok- i will look for that in forscan also- i am not super proficient with forscan but am able to make changes so thats promising!
thanks-

 

it’s in the services section.

if you have forscan on your phone you can run it from there. You don’t need the laptop version.

 

Per the Owners Manual, the message will be issued and the DEF light illuminated "when the DEF is contaminated, low or someone has tampered with the DEF system."

Any possibility that you topped off with bad DEF?

 

The "DEF Fault" warning doesn't come on for low DEF, it comes on because the ECM has triggered it due to some sensor in the system that is out of range.
There should be a code or codes posted related to the warning.

 

ok
i tried to use my phone but the adapter wasnt able to connect to my phone-
the alarm didnt come on today which is odd.......
i topped of at the station at the pump so i dont think it was contaminated......
i will hook up a scanner and see if it stored a code........ besides the one (P220E)for the nox sensor i havent figured out yet

 

Mine got confused like that after a heavy tow when I ran it till like 500 or 250 warning. Was getting 5-8mpg for a few hours.

Put a jug in and the 250 warning light came back on shortly after. Which wasn’t convenient since I was about 200 from home.

Long story short is run it for a while and it will probably adjust back. It was a little off for a moment but above 500 range so no light.

 

Assuming I was in the right place, I wasn't able to get the service procedure to work from my phone.

 

hmmm i cant seem to get the adapter to work with my phone or ipad but it worked with my computer. i believe it worked originally?
frustrated......

 

Yeah, probably a NOx sensor. I think they are a backordered part these days

 

Funny, I must be speaking a different dialect of English. I translate that message to read "Please delete me and never worry about this again."

 

where are you reading that in plain English?