Got this message last week on my trusty PIXMA MP960. Tried all of the procedures mentioned above at least a dozen times with no luck. Then I unplugged and let it sit overnight, In the meantime I removed all of the ink and the print head and cleaned the excess ink off the printhead ink jets. Next morning I plugged it, reinstalled the printhead, installed the ink, turned it on and viola! it worked. Then I decided to test it by printing a test page. Everything looked good except for the top black ink pattern for the PGBK ink cartridge, the print was so faint and blank as to be almost non existent. I did several head cleanings with no luck, then did deep cleaning with little success. I created a test page that had a full page of letters and printed it 3 dozen times and started to get better results but still had areas that did not print well. Decided to buy print head solution to cleana and "unclog" the jets thinking they may have dried out when the printhead sat overnight with no ink in it. Did a thorough cleaning and reinstalled everything. Turned on the printer and got the dreaded U052 message! I've tried to repeat what I had done previously but no luck. Even bought another print head off of eBay but I get the same error msg so I don't think it is a printhead issue. Love the printer, scanner specs are better than any other current models regardless of brand and prints pro photo quality prints. Want to save it, so I'm bundling it up and taking it to a local Canon authorized service center even thought it is out of warranty. Does anyone have any other ideas? Some have said it is a temp sensor issue. How is this corrected? Could it be an ink cartridge related issue with non-Canon or refilled cartridges? Is there a way to "reset" or override the error so at least the scanner can be used? This should be a simple software/firmware update to allow bypassing the print error and still use the copy/scanner functions.
