What Is a Tier 1 Credit in Auto Loans?. When you go to borrow money to buy a car, the lender will check your credit and get your three-digit credit score. The credit score looks at everything on your credit report and summarizes it into a single number. Higher numbers indicate a better credit history, and lower numbers indicate the opposite. Some lenders group borrowers into tiers based on their credit scores, with tier 1 or A being one of the highest categories.