Hi wnwang,
The 5000 error is a generic internal error code. Unfortunately, it could mean one of many things. To resolve the 5000 error, please follow the following steps:
1. Turn off the printer and disconnect the power cord and USB cable.
2. Remove paper from the automatic sheet feeder (in the back).
3. Gently pull jammed paper out, if any.
3-1. If paper is visible from the ASF, use both hands to pull the paper out slowly.
3-2. If paper is visible from the paper output slot, use both hands to pull the paper out slowly.
4. If the paper tears and a piece of that remains inside the printer, open the printer cover and remove the paper from inside the printer.
5. Check ASF with a bright light to check for obstructions. Remove any if found.
6. Open the rear cover to check if the paper is jammed.
7. Pull out the cassette and check if the paper is jammed inside the cassette area.
8. Load paper back into the ASF or cassette.
9. Reconnect the power cord, turn on the printer and confirm that the Alarm light is off. (If there was any jammed paper remaining in the printer, the paper may be automatically ejected.)
If the above procedure does not resolve the 5000 error, please contact our support group using the following link:
http://www.usa.canon.com/cusa/consumer/standard_display/contact_us_consumer
