Canon EOS 1DS MARK II 9443A009 Instruction Manual (en)

If a camera error occurs, <Err xx> will be displayed on the top LCD 
panel. Follow the instruction below to resolve the respective error code. 
If the same error occurs often, something is probably wrong with the 
camera. Jot down the “xx” error code and take your camera to the 
nearest Canon Service Center. 
If an error occurs after you take a picture, the camera might have 
missed the shot. Press the <
> button to see if the image 
appears on the LCD monitor. 
Error Codes
Error Code
Err 01
Communications between the camera and lens is faulty. 
Clean the lens contacts. (p.9)
Err 02
There is a problem with the memory card. Try any of the 
following: Remove and re-install the memory card. Format the 
memory card. Use a different memory card. 
Err 03
Too many folders in the memory card. Replace with a formatted 
memory card. 
Err 04
The memory card is full. Erase unnecessary images in the card 
or replace the memory card. 
Err 99
An error other than the above has occurred. 
This error may occur if you use a non-Canon lens and the 
camera or lens does not operate properly. 
Remove and reload the battery.