The authorized dealer in your area may pull your credit to determine which lender programs you might qualify for. The reporting agency they will use varies by location. Some dealers have systems in place where they don't even need to generate a hard inquiry to check your credit. Also, it is likely that the lender that your application is submitted to will also generate a hard inquiry. Again, the reporting agency they will use will vary.
Keep in mind that while a hard inquiry will normally result in a decrease in your credit score, the credit agencies understand that people shop around for loans. Credit scoring systems have been designed to count multiple hard inquiries for the same type of credit as only one inquiry as long as they are made within a short period of time.
There is no minimum credit score you need to have to qualify for a car loan. Your application will be evaluated on an individual basis, and many factors will be taken into consideration. Therefore, it is impossible to put a number on it.