The day after it received $6 billion in capital from the federal government, GMAC, the financing affiliate of General Motors, began aggressively trying to draw consumers back into dealerships on Tuesday.

GMAC said it would begin making loans immediately to borrowers with credit scores of 621 or higher, a significant easing from the 700 minimum score the company started requiring two months ago as it struggled to stay afloat. And G.M. said it would offer a new round of low-rate financing, including zero percent interest on some models.

The infusion of capital from the Treasury Department late Monday was seen as critical for both GMAC and G.M., which relies on the lender to finance car buyers and dealer inventories. GMAC is jointly owned by Cerberus Capital Management, the private equity firm, and G.M.

The Treasury will buy $5 billion worth of preferred shares in GMAC as part of the $700 billion financial rescue known as TARP, for Troubled Asset Relief Program, and it will lend $1 billion to G.M., which, in turn, will invest $1 billion in GMAC.