This repair started with e00025-001. Removed K hopper and cleaned toner hopper sensor, reinstalled everything and upon power up e00066-001. Checked pre transfer shutter movement, clean the sensor with no change. Can hear shutter open the go back home upon home it clicks until code appears.
Replaced pre transfer assembly with new new unit, same error upon power up.

Checked wire harness for shorts or open non found also pins in connections, non bent or broken. I am now at a lost. I also tested both primary and pre transfer in another c7570i primary worked fine but the pre transfer threw e66-01, thats when I ordered the new unit, but as mentioned above it failed in the c7580 and also in my test c7570.

I did try the pre transfer from c7570 in the c7580 and errored but back in the c7570 came to ready and printed with no problem. These are my symptoms as I can recall.

My question(s) are: would my initail be cascaded with a board failure with the e025 being the lowest in order thus first to display? Could I created the e066 during my first repair? Lastly, what to try now?

Thanks for your input.