It is likely that you will be required to provide a down payment if you are to be approved for a bad credit auto loan. The subprime industry standard is 10% of the car's price or $1,000, whichever is less. It also helps your approval chances if you are able to pay tax, title and license fees up front.
If you have poor credit, lenders see you as a high-risk borrower, so they want you to have more skin in the game. This is why nearly all subprime lenders require a down payment in the form of cash, trade equity, or a combination of the two. In certain cases, it may be possible to qualify for a zero down auto loan, but these instances are uncommon.