Akio Toyoda chief executive of Toyota Motors apologized Friday for the problems that led to the company’s recall of more than 8 million cars, but it did not announce another recall of its popular Prius Hybrid, despite reports of brake problems. The recall affected 8.1 million vehicles worldwide and will cost the company an estimated $2 billion in repair costs and lost sales due to a sticking accelerator.

Toyota has far greater financial resources than most of its rivals, such as: General Motors, Ford Motor (F, Fortune 500) and Chrysler Group. But the quality issues do pose a financial challenge for the company. Friday credit rating agency Standard & Poor’s placed its debt on credit watch, meaning it faces the risk of a downgrade that could raise its borrowing costs.