Canon MF4600 Series Basic Operation Manual page 218

Message
SYSTEM ERROR
TONER COVER OPEN
CLOSE COVER
TONER LOW
PREPARE NEW TONER
UNKNOWN USB DEVICE*
USB MEMORY FULL*
* MF4690PL Only
11-20
Description
Some kind of error has
occurred in the machine.
A cover is open.
The toner is running low.
A USB device which is not
supported (e.g., USB mouse,
USB keyboard) is connected to
the USB memory.
The USB memory is full of data
or the number of file limit has
reached.
Action
Turn off the main power switch,
wait for more than 10 seconds,
then turn it on again. If the
message persists, turn off the
main power switch, disconnect
the power cord, and contact
your local authorized Canon
dealer or the Canon help line.
Check the cover, and make sure
that it is completely closed.
Prepare a new toner cartridge.
Do not connect anything other
than a USB memory.
Get enough space in the USB
memory or organize your
destination folder from your
computer.