WP4545 has stopped printing yellow. Help would be appreciated.

Please would someone give me advice.
I was printing some newsletters when I noticed that they had gone pink.
I suspected yellow had gone. So I changed cartridge. still no yellow.
So I bought an Epson cartridge (ouch) and put that in . Still no yellow.
Any ideas what I can do next?
The printer is an Epson Workforce pro WP4545DTWF Multifunction Inkjet printer.
Thank you fro reading this.

Are you using genuine Epson cartridges ? Did you do a cleaning cycle via the driver ?
Did the yellow ink disappear suddenly ? Or slowly with missing lines ?
Could you please upload the nozzle check print as an image (x.jpg format ) .
Is the unit still under warranty ? Are you printing regularly or with longer interruptions ?

Thank you Fingers!
No I was using cheap cartridges.
Not sure what you mean by cleaning cycle via the driver. Sorry.
Yes it disappeared suddenly. No missing lines.
I will upload the photo of the nozzle check in a few moments. Complete gap where the yellow should be.
As a further test I tried to print an excel sheet with three cells only. They were shaded red then blue then yellow. Red and blue ok, nothing at all in yellow.
All three squares print if I switch from colour to black.
Not under warranty. Purchased in 2013.
I print every day, mostly black. But print colour a few times each week.
It was in the middle of printing 50 two sided colour newsletters when the yellow disappeared.
Thank you so much for your help.
Tim

Are you running the printer on a Windows computer ? When you want to print something you can call up the printer properties via the driver menu for various settings - paper size - quality and more, and you should have a separate 'Utility' driver tab with various functions like a nozzle check, a function button for nozzle cleaning, software updates and more. You should run such a nozzle cleaning cycle and another nozzle check afterwards to see whether there are any changes visible and one more again if necessary. You may have as well the chocie of a standard cleaning or intense cleaning cycle with some drivers.

Thank you Fingers.
Yes I am using a windows computer.
I found the printer properties maintenance options.
I didn't see anything referring to a cleaning cycle or intense cleaning, but I did click on nozzle check (last time I selected this on the printer) .
It came up on the PC "Head cleaning in progress".
The subsequent printout showed no change to the printouts that I attached i.e .no yellow.

I tested again with an excel sheet . I printed a kind of Romanian flag.... except no yellow at all printed.

You have been very kind. Do you have any other ideas/theories?

Thank you
Tim

You are running a Printer with stationary cartridges. Between the cartridges and the printhead, there are tubes. The yellow tube was completely emptied and that is likely why it disappeared during printing.
Having installed a new cartridge will not immediately solve the problem. The tube between the cartridge to the printhead must be refilled with ink and then at the same time ALL the air caught inside the printhead must be removed by operations either as cleaning or system flush. This will be costly.

This is a case of why I do not recommend all these type of printers with stationary cartridges for general use. When something goes wrong, there is a lot of hurt that is going to come down.

Continue performing multiple cleans until the yellow starts appearing and by that time possibly some of the other colors will also need to be replaced.

Your inexpensive cart might have been underfilled relative to the what the printer was expecting via the chip count. So it possibly actually held less ink than what the chip was telling the printer. Beware of the other colors running out as well with the same issue or else............you will have deja vu with the other colors and will drive you nuts.

Thank you for the time you have spent helping me.

So , for the avoidance of doubt, you are recommending that I keep doing "nozzle checks" until yellow appears?

I suppose if it never appears it is a bigger problem.

Thank you
Tim

Head cleaning which will waste and consume a LOT of ink. See if the colors cleaned are selective to colors only. Good luck.

The printer does a head /hozzle cleaning after each cartridge change, that's the notice you may have gotten if you didn't start the head cleaning by yourself.
The Epson utility tab typically arranges the button for the nozzle check first, continues with a nozzle/head cleaning function, head alignment and some other depending on your printer type.
The nozzle check just prints the patterns you posted above but does not do any manintenance/cleaning function. The other colors and ink channels appear to be o.k. .
Could it be that you got a warning by the firmware that you should purchase new cartridges because the ink level is getting low - Epson likes to link you directly to their shop to purchase them there. This may be the time to replace such 3rd party cartridges already before they report actually empty. @mikling is describing an effect that the chip data and the actual ink contents don't match and could get you in such situation, I got into that several times as well in the past.
As recommended you would need to do several cleaning cycles to get the yellow tube filled again, you may use a cheaper (properly filled ) 3rd party cartridge as well.
Did you always use the same type/brand of yellow cartridge before yellow stopped working ? Or did you mix those from different suppliers ?