0002, aka Data Check and Log Check, refers to a disc and a NAND title installed from disc used during Wii Factory Setup. The WAD from which this title is installed, known as "DataChk.wad", does not always have its contents deleted after factory setup, and as such multiple versions of 0002 have been recovered from Wiis.
This program reads the SD card for an "all.ini" file, then performs various tests based on instructions in the file. However, it is not the main RVLAging test program, as this is 123J/0000dead.
Role in the Factory Process
Main Article: Wii Factory Process § DCLC Disc Information
There are different versions of the WAD file, and they are not present on all Wiis. As noted above, 0002 does not contain any test programs, it just runs them off an SD card with a file called all.ini. Since it reads the file from the factory SD card, we do not know much about actual information from the test programs. all.ini contains listings for test programs only for Wii prototype models and even some GameCube models, so it is reasonable to deduce that it dated back to pre-Wii and had a use for the GameCube, and not all files are present on SD cards; many of the programs of the programs would not even run on a standard Wii.