Emmc read test drive unsuccessfull

This means that the internal storage is starting to fail. I highly recommend that you back up any critical data (if possible) before the drive fails completely and becomes inaccessible.

Unfortunately, eMMC storage is soldered directly on the motherboard and is not replaceable. The only way to resolve the problem is to replace the entire motherboard with a new one. However, it appears that your model can accept a 2.5" SATA drive or a NVMe SSD, bypassing the eMMC storage, which may continue to display error messages upon startup afterwards. I recommend installing a NVMe SSD, as the bracket, connector, and related mounting screws for the 2.5" drive may not be present inside the system. The NVMe SSD only requires 1 screw to hold it in place, but remove the bottom cover and double check that it's there in its post before proceeding. If the eMMC holds up, you can use a program such as Macrium Reflect Free to clone the existing contents over to the NVMe SSD. If you are unable to do so, then you will have to reinstall Windows from either the Dell recovery image or a Windows Installation Media USB, and afterwards attempt to recover any personal files from the eMMC storage.

Inspiron 3482 Service Manual (PDF)