As far as I know, the CP 4 was first used in the 6.7L Ford. Not in the 6.4L engine. Siemens pump in the 6.4L ?????? I am not sure here though.
But I am convinced that Ford does have a winner with that 6.7L diesel. Pump issues are real, but since I owned one at the time, I really checked and read as much as I could about the issue.
It seems failure rates for the pumps are very, very low, with anywhere from 97% to 99% failure free operation rates, depending on where one is reading.
So the odds are with almost anyone buying this engine.
And appears Ford made changes to the pump in their 2015 models. What changes they made exactly are unknown to me. But it nevertheless appears to be a change made to improve the already good reliability rate.