Hi guys, Since today my Macbook Pro (Retina, 15-inch, Late 2013) is making a strange buzzing sound every few seconds. It goes in the same interval. 4 seconds silence, 1 second buzzing. Video of the location and sound: https://vid.me/XlXG I tried the diagnostics and it brings up this: There may be an issue with the fan. PPF004 / PPF003 Is it the fan? And how severe is this problem?