Canon imagePROGRAF GP-4000 - Manual (Page 821)

100F
Cause
A printer error has occurred.
What to Do
Turn off the power, wait a moment, and then turn it back on.
If the error appears again, make a note of the detailed error code (ECxx-xxxx) that appears on the touch
screen, and then turn off the power and contact a Canon customer service center.
Detailed error codes
EC17-202F
821