so you can see the cyan is perfect, red and magenta are perfect, light shades of other colours are ok but yellow and green as in that test print document I did is very faint yellow and green is teal.
if you cant view these I have attached a link for a zip file of the photos here
To me it looks like you have lack of developer in your yellow housing.
Verify by swapping R1 and R4 to see if problem stays with yellow. If it moves to black, replace the imaging unit.
Below advise is not approved, just a suggestion from one user to another.
Secure a developer charge part number is 675K67550
Remove the yellow toner and tap its base against the ground a couple of times to move the toner to rear of the container. slide the toner door of the toner container open. use a funnel to put the developer into the head of the yellow toner container. Close the toner container door. Install the toner back into the machine.
Now solid run yellow. The developer will follow the toner path and hit the housing and recoat the mag roll.