Greetings,
Canned air and Q-Tips moistened with alcohol can sometimes help. It really depends on whether or not the sensor is just dirty or has actually failed. The printer itself is a little over 13 years old now, so it's no longer serviced by Canon.
~Rick
Bay Area - CA
~R5 C (1.1.2.1), ~R50v (1.1.1) ~RF Trinity, ~RF 100 Macro, ~RF 100~400, ~RF 100~500, ~RF 200-800 +RF 1.4x TC, BG-R10, 430EX III-RT ~DxO PhotoLab Elite ~DaVinci Resolve Studio ~ImageClass MF644Cdw/MF656Cdw ~Pixel 8 ~CarePaks Are Worth It
