My workcentre 6515 shows 062-380 error and does not scan anymore. Switch off and on again did not help :-

SOURCE: workcentre c2424 is showing system error 39,003.40:117010

That is a document feed or scanner fault. Often times it is simply that molex connector working loose. It is the connector mounted vertically next to the main power cord on the right rear side of the machine. That bottom screw can be dificult to tighten. What I would try first is to shut the machine off, unscrew and disconnect that conntecot totally then firmly slide it in and get both the top and bottom screwss tight. Like I said, the bottom thumb screw can be hard to tighten even with a screw driver because it is a pretty soft rubber the tighteners are made out of.
If that doesnt work. go to the back and disconnect the document feed to scanner cables and reconnect. Other than that, you pretty much have to replace the feeder/scaner assembly since very very few parts are spared for that .