Can I redeem a DLC for a game I don't have?

Hey there shadowslice3102.

To clarify are you able to access the DLC but not able to access your save now? Having a bit of trouble understanding the issue you're experiencing currently.

Yes you can redeem codes for some DLC you already own. If you already have the Cerberus Network don't waste the code by trying to redeem it, sell it on eBay or give it to a friend who bought the game second hand.

has your friend set your Xbox as his Home Xbox?

yep, he did

has your friend set your Xbox as his Home Xbox?

Another update, after receiving a warthog from the in-game message center on the 27th and another from an in-game pop-up today, I just closed my game and checked manage games and the warthog dlc appeared under ready to install. I installed it and rebooted
my game and I don't see a third warthog anywhere and no messages in my in-game message center to redeem another one but I'm assuming that's because I already have at least one in my garage. I also checked the "DLC CARS" section of the Autoshow tab from one
of my festival sites and I don't see a warthog redeem there, I only see the 15 cars that have so far come with my ultimate edition. So everyone who redeemed their codes should now check ready to install for the warthog dlc file.