Canon imageRUNNER ADVANCE C2000 Series Technical Workbook page 59

Cause
The contact holder unit[1] was not fitted into the emboss[a] properly. This interfered with the terminal[2] of
the contact holder unit from contacting with the contact plate[3] of the drum unit as shown in the photo [A],
and resulted in the occurrence of the symptom. Normal state is shown in the photo [B].
Service work
Check the adequacy of fitting of the contact holder unit following the procedure below to fix the failure.
1) Turn OFF the main power switch.
2) Open the front cover, and then open the retainer cover[1] and the grip[2] of the drum unit.
3) Remove 2 screws [1] and the inner cover [2].
pg. 57