While many car dealers do not offer Chapter 13 financing, some do, and so it is important to know what's in store for you if this is something you need to do.
First, be prepared to finance a used vehicle at a high interest rate with a lender that you've probably never heard of. Also expect to put around 20% down via cash or trade in.
Second, get ready to get your Chapter 13 Trustee's approval. This will require, among other things, proving to the Trustee that you can afford the vehicle.
It isn't an easy process, but it's something you have to do if you are in a Chapter 13 and you need a new vehicle.
Finally, make it as easy as possible by buying the cheapest car available. Low cost = low payments.
Good luck! You'll get through it!