Canon EOS-1D X Mark III DSLR Camera (Body Only) - Manual (Page 905)

Sensor cleaning problems
The shutter makes a sound during sensor cleaning.
Although there is a mechanical sound from the shutter during cleaning after [ Clean now
] is selected, no image is recorded to the card ( ).
Automatic sensor cleaning does not work.
If you repeatedly turn the power switch < > and < > within a short time
period, the < > icon may not be displayed ( ).
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