Let us know what you find. Often it is a sensor malfunction.

 

I just had this on my 21 last week! It’s the rubber coupler between the boost tube and the throttle body. It’s visible up top at the front of the engine just behind the fan shroud. At first, mine appeared fine, but once removed, it was cracked on the back side allowing air to leak. Heat and oil apparently eat these up pretty fast and it was in much worse shape than I would have expected for 4 years and 60k miles. 2.5x4 inch silicone intake coupler and two new clamps from Amazon for about $20 and good as new.

 

Good catch @Fastlane! Cody Phillips (@CP's Garage) says this hose will fail sometime, it's a matter of when, not if. I changed mine out last week and the old one is still intact so it is now a spare. The photos below show the items Cody recommended. Overall fairly easy. Kind of odd the two fittings are different size, makes it a little of a struggle putting it on.

I think everyone should do this before it becomes an issue.

 

Update on this. Truck is still at the dealership, saying both Nox sensors need replaced. Dealership told me "Nox 1" was ordered and shipped, but "Nox 2" is on back order and there are none available right now with no ETA for when they will be available.
Does anyone happen to have a part number for this to do my own research? Really frustrated.
Thanks,

 

This is from the Ford 3.0 Diesel Coffee Table book.

#3 and #10 are NOX sensors and #4 and #11 are NOX modules. Lakeland Ford lists these parts numbers for the 2018 Ford but i dont know if they are the same for 2021 or if they are in stock:

 

Just looked at those prices! They aren't cheap. If you have to pay you might try to find someone who had deleted and buy theirs.

 

Just a suggestion….

suggest to the dealer that they check the coupler we mentioned above before throwing expensive parts on the truck. When mine leaked, it threw codes for both sensors also. If the coupler is completely blown, it’s likely going to keep throwing the codes. That doesn’t mean the sensors are bad unless they are actually testing the sensors themselves To know.

my experience has been that even big ford dealers who have good reputations often have little knowledge of these 3.0 diesels. There just weren’t very many of them churned out and they don’t go in very regularly for the dealer to deal with them and be familiar.