An index of 1.00 means that the frequency of failures is matched to its percentage of vehicles on the road, and thus, has average reliability.

FORBES: How To Predict What Will Go Wrong With Your Car Down The Road

To measure the frequency of repairs for a particular vehicle, it compared the percentage of reported check engine failures for that model to its share of all 136 million 2002-2012 model-year vehicles on the road.

FORBES: How To Predict What Will Go Wrong With Your Car Down The Road