Gradation Result All 0 for Yellow only in Printer Gradation fine in Copy Gradation

[systemnova]

Although no error codes are being thrown I'm findign that at 600dpi and 1200dpi the gradation yields all 0's only for the yellow adjustment result. All other results seem fine.
Print's seem ok also, as i guess the default value for yellow is sufficient. But concerned that whatever sensor is failing might explain my issues with grey colours in scans.
Any suggestions on what part might be failing to cause this issue?

[Synthohol]

did you start by background data reset and stabilize before going into the gradation adjustment screen?
if that fails then run toner add. if that has no joy usually something is physically wrong.

[Tech09]

So when you're running Gradation Adjustment, all of the adjusted values for Yellow are 0 and those values don't change at all if you run gradation again? That would be perfect yellow but I've never seen one not vary at least a little in the adjusted values.

[tsbservice]

I would advise to start long twisted posts with model number... You won't believe it but sometimes it matters

[systemnova]

Think i sorted this one, turns out Switch 105 Bit 1 - "Enables the function that targets CMK for gradation correction to fix issues where images become more reddish when gradation adjustment is executed."
Didnt think it would mean 0 for Y in gradiation. Can't tell you how many other things i tried prior to this haha