Ef4doorFTW

My car has been throwing code 20 (ELD). Also my battery died today and there was no "visible" reason for it be dead, lights weren't on the car was off. Would those have anything to do with each other? Also to fix this I've read u need to do something with the fuse box under the hood. Do you have to replace the while thing or what? Or would it have something to do with the alternator. Any help would be nice.

Thanks for reading