Receiving error c2814 and c2454 on c6500

[copies]

I was receiving error c2814 error. So I swaped the black drum with the yellow drum and now I receiving error c2454. I swaped the drums back and still getting the error c2454. Any ideas?

[anothertech]

Sounds like a bad black toner density sensor in the black dev unit.

[copies]

Thank you for your help.I will replace the black dev.

[ESA]

Did you run a Auto Gamma Adjustment? Values on the drum swaps won't match internal values. Make sure you blow clean the drum potential sensor behind the drums when you replace or remove.