In the printer, check the ribbon cables from the scanner, if they are a bit loose it can cause this error
Got this from usa canon.com website click here and type error code in the search box
a list of the error codes will be displayed and you can then click on the relevant one.
"Issue: ERROR LCD: Error Code 5010
Solution: Press ON/OFF switch to reset the multifunction device
Reset the device when it is not functioning properly.
If the device is not functioning properly or to clear memory, reset it.
1. On the operator panel, press and hold the <ON/OFF> button for one second. (The display will go blank.)
Note: It may be necessary to unplug the power cord if pressing the ON/OFF button does not shut off the printer.
2. Wait approximately ten seconds and then press the <ON/OFF> button again.
3. Wait until the device has completed its cycling process before submitting another job request."