I recently have experienced the 5200 and the P08 error on my Canon PIXMA MP250.
Here are my tips on how I’ve fixed the error.
In order to reset either one of these two errors: 5200 or P08, follow these steps.
Your printer should have the power cable connected but it should be turned off.
Press these two buttons at the same time: “Power” and “Stop/Reset”.
When you see the Power LED on , press “Stop/Reset” twice while the “Power” button is still pressed.
Take your finger from both buttons, “Power” and “Stop/Reset”, and wait around 30 seconds until you should see on the display this character: “o”.
Press “Stop/Reset”, four times.
Finally, press the “Power” button twice and them turn the printer off.
Open the printer.
Either of the mentioned errors, 5200 or P08 should not occur at this point from now on.