This error indicates that an internal error has occurred which may be resolved by resetting the printer. Please follow these steps for isolating and resetting the printer:
1. Open the printer's front cover, and then open and close the print head lock lever (do not remove the print head).
2. Make sure all ink tanks are seated properly.
3. Make sure all packing materials have been removed.
4. Make sure no paper is jammed in the printer.
5. Disconnect the printer cable from the printer.
6. Close the front cover and turn the printer off.
7. Unplug the printer from the power source, and then plug it back in after five minutes.
8. Power on the printer.
If the error returns, the printer will require service options. Please contact a technical support representative who can provide you with your service options. They can be reached by calling 1-800-652-2666 between the hours of 10AM and 10PM EST, Monday through Friday.
If you are unable to manually move the print carriage so that you can remove the ink, your PIXMA MX870 would require service.
You are eligible for Canon's Upgrade Program. This is for out of warranty units which have been diagnosed to require service, or for some reason are incompatible with a new or upgraded system. This option allows you a one-time opportunity to purchase a replacement product, discounted from the list price.
To help you get up and running quickly, we also offer free standard shipping (if the order is completed by 12:30PM ET). If you would like to take part in this option, please call our Sales Department at (866) 443-8002 seven days a week, 8am to Midnight. Let them know you have been working with technical support and the Canon Upgrade Program was offered.
This error may occur when there is a loose object stuck inside the printer or if one of the ink tanks was not seated properly.
Please try the following:
1. With the cover of the printer open, unplug the power from the back of the printer.
2. Look for any loose objects or packing material in the printer, clear if necessary.
3. Try gently moving the ink tank holder as close to you as possible. Try pushing the closest ink tank down. Once clicked into place, try moving the ink tank holder closer, repeat as needed.
4. If you meet resistance, do not attempt to move the ink tank holder any further.
If the issue persists, find more help at Contact Us.
I tried all of the suggestions above, but nothing worked.
So as the above message suggested I Contacted Canon at 1-800-652-2666.
With the very helpful customer support person we determined it was not a problem with my printer refil ink cartridges. Nor was it a seating problem.
IF THE RED LIGHTS DO NOT LIGHT UP WHEN YOU RESEAT THE INK CARTRIDGES THEN IT IS A PROBLEM WITH THE PRINTER.
In this case you will need to take the printer in to get repaired, they cannot help you past this over the phone.
I urge you to call Canon if you are in my same situation.
The nearest repair center was more than an hour from my home. The same customer service rep I spoke with was able to give me a great deal on a new printer during the same phone call and as I write this it is being shipped to my house. This is how I was able to solve my printer problem when error code C000 came up on my printer screen.
Hope this helps someone...