Dell Photo All in one 924 - shows carriage jam but paer is clear
The all-in-one printers are notorious for getting small pieces of paper lodged in the gear assemblies both in the back behind the paper pickup roller and in front under the print head. Dust also can collect causing false errors. I would first blow the thing out thoroughly with a can of compressed air because honestly any other solution is probably going to cause you more time, money, and trouble then just replacing it the printer; especially if the Dell printer is under warranty.
But for the sake of diagnosing the issue specifically...Look for damage in and around the print head, especially the bundle of wires attaching to the back of the print head. If they are damaged it will generate a carriage jam. Also, listen to the head when it tries to move, if it clicks or pops or if when you restart the printer it fails to move across and back to align itself, your drive gear on the print head is stripped or the assembly itself is not functioning.
If it moves and aligns itself but then gives a carriage jam anyway, it's obviously not jammed because it moved. That means that the control board or system board may be damaged and these are VERY difficult to replace without disassembling the whole printer.