A Brief History of Error 99

Canon no longer officially comments on Err codes, but if we go back to the golden days when they did, we can unravel a lot of the Err99 mystery almost immediately. Back in 2000 Canon released its first mainstream DSLR, the 3.1 megapixel D30. The manual contained a helpful list of the camera’s built in error codes:

• ERR 09: System Error. This error occurs when the EOS D30’s self-checking system processing time has exceeded the specified limit.
• ERR 22: CF DRIVER. Data cannot be written to the CF card for some reason or another.
• ERR 23: NO SPACE LEFT ON THE CF CARD. Space remaining is smaller than needed to complete the write operation.
• ERR 50: CF FORMAT. The CF card cannot be formatted in the camera.
• ERR 51: PLAY MODE. The CF card cannot be played back in the camera.
• ERR 80: SHUTTER. The shutter operation sequence has not been completed correctly.
• ERR 81: MIRROR. Mirror up/down status cannot be detected during shutter release.
• ERR 82: STROBE. The built-in flash cannot be charged.
• ERR 83: POP UP. The built-in flash’s pop-up operation cannot be detected.
• ERR 84: LENS COMMMUNICATION. Electronic communication with the lens cannot be established, or the aperture diaphragm cannot be controlled.

In 2002, the D60 was released. It had a reduced set of error codes:

• ERR 01: LENS COMMMUNICATION. Electronic communication with the lens cannot be established, or the aperture diaphragm cannot be controlled.
• ERR 02: CF DRIVER. Data cannot be written to the CF card.
• ERR 04: NO SPACE LEFT ON THE CF CARD. Space remaining is smaller than needed to complete the write operation.
• ERR 05: POP UP. The built-in flash’s pop-up operation cannot be detected.
• ERR 99: SYSTEM ERROR. There is an internal malfunction detected during the camera’s self-checking procedure which is executed before every attempted exposure.

Key point: Error 99 is a catch-all which can mean almost anything went wrong.

As far as we can tell, the Canon error codes have remained the same through the 50D and 5DMkII camera bodies, at least nominally. The more recent bodies have added an Err 06 code for ‘sensor cleaning unit malfunction’, and there are now Err 10, 20, 30, 40 . . . 80 codes on 5DMkII cameras (with the useful message ‘Shooting is not possible’. Duh!). Also some more recent manuals now define Eee99 as “an error other than one of the above (Err01-Err06)” has occurred. The only semi-official statement from Canon in recent years is one from Chuck Westfall in TheDigitalJournalist saying “[Err99] is a non-specific error code which can be caused by a wide range of malfunctions. … a variety of problems can be caused by the use of non-Canon accessories such as lenses, memory cards, battery packs, electronic flash units, etc.”