bizhub c451 covers transfer belt with cyan toner during stabilization on boot up

[paperjam]

I have a bizhub c451/ineo +451 that covers the transfer belt in cyan toner during the stabilization process on start up.
This gives me a P-21 code right away. I have tried a cyan IU and transfer belt and still same issue. I have tried a HV2 board and still did not fix issue. I have also cleaned IDC sensor's rear and front. Any ideas what could be causing this issue???

[acusso1234]

You can try a total reset and a new reinstall, than gradation adjust.