CAT 299D3 XE

Can anyone help me with understanding what a step pump is and how it would de rate the motor into limp mode on a 299d3 without throwing a code?
I’ve been having nightmares with this new machine from one problem to the next and now I’m told it’s the step pump and it “MIGHT” be covered under warranty. This is a 2020 with 72 hours on it so I’m getting concerned with my CAT