When the check engine light turns on in your car, it could indicate a slew of problems that range from minor issues like a loose gas cap to more extensive problems such as a faulty oxygen sensor. Many drivers assume the light can be ignored for at least a little while, but this practice can lead to further damage and more costly repairs. CarMD recently released its second annual Vehicle Health Index, which sets out to examine car repair and auto maintenance trends year-over-year.

"It's encouraging to see that despite many fiscal and environmental challenges, the automotive industry continues to make positive strides in designing vehicles that last longer," said Art Jacobsen, vice president of CarMD. "Despite the fact that the average vehicle age is at an all-time high of nearly 11 years, 2011 saw a decrease in the average national auto repair costs. However, the CarMD data also shows that consumers continue to put off small repairs, which can result in much more expensive, catastrophic repairs and negatively impact fuel economy."

The report indicates overall repair costs were down about 6 percent since 2011, which is likely a combination of drivers putting off maintenance and mechanics adjusting their labor costs to compensate for the increased price of parts. Replacing the oxygen sensor was found to be the most common repair for the second year in a row.