The most common “check engine” light repair is “replace Oxygen Sensor.” A faulty O2 sensor costs less than $300 to fix, but can lead to as much as a 40% reduction in gas mileage if ignored – immensely important to note as fuel costs rise.

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CarMD.com Corporation is known for its unprecedented database of real-life repairs and “check engine” data from our network of thousands of certified automotive technicians across North America.

As a result of compiling the industry’s most comprehensive database of diagnostic trouble codes and repairs for “check engine”-related problems, CarMD is uniquely positioned to provide data on a wide range of vehicles and the reasons they experience these problems.

Each April CarMD taps this database to release the CarMD® Vehicle Health Index™ of “check engine” problems, repairs and related costs. Each summer, CarMD releases state rankings or repair information and costs. In the fall, the annual CarMD® Vehicle Health Index™ Manufacturer & Vehicle Reliability Rankings is released. With these indices, consumers, media and industry analysts can compare year-over-year car maintenance and repair trends and patterns.

Click to see current Index Data