Canon EOS 5D Mark II Instruction Manual - Page 165

Error Codes If a camera error occurs, "Err xx" will be displayed on the LCD panel. Follow the instruction below to resolve the problem for 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 Code Err 01 Err 02 Err 04 Err 99 Countermeasures Communications between the camera and lens is faulty. Clean the lens contacts. (p.11) There is a problem with the CF card. Try any of the following: Remove and re-insert the memory card. Formatting the CF Card. Use another CF card instead. The memory card is full. Erase unnecessary images in the card or replace the CF card. An error other than the above has occurred. Press the shutter button halfway or remove and reinstall the battery. This error may occur if you use a non-Canon lens and the camera or lens does not operate properly. 165