The most common “check engine” light repair is “replace Oxygen Sensor.” A faulty O2 sensor costs less than $250 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.

CarMD.com Corporation has released the April 2012 update of the Vehicle Health Index, its unbiased collection of vehicle health and reliability data, revealing the most common failures illuminating the “check engine” light, along with the most common repairs, and parts and labor costs for each incident.  

The latest data reveals that it is always important to pay attention to small problems and warning signs for your car. Small problems lead to big problems with bigger price tags. Ignore a spark plug problem (currently the no. 6 most common problem) and a $10 part could turn into a $300 “ignition coil and spark plug” repair (currently the no. 4 most common repair). Ignore that and you may need to replace your car’s catalytic converter at an average cost of $1,000 (no. 3 most common repair).

Vehicle age plays a role in the most common repair ranking.
The no. 1 “check engine” repair for model year 2001 vehicles, which is in line with the average vehicle age, is a damaged or loose gas cap (8.26%). The gas cap is also the most common culprit for newer vehicle repairs, accounting for a whopping 26.9% of fixes on model year 2011 vehicles. The average vehicle age is now 10.8 years old.

Each of the 5 most common repairs will reduce gas mileage if ignored (Replace oxygen sensor, tighten or replace gas cap, replace catalytic converter, replace ignition coil(s) and replace mass air flow sensor).

Several new repairs appear on the top 25 this year, including “Inspect Battery and Charging System and Repair as Necessary” (no. 16), “Replace Wheel Speed Sensor(s) (no. 17), “Replace ABS Control Module” (no. 20) and “Replace Air/Fuel Ratio Sensor” (no. 24).

As the average age of vehicles rises, those that receive less preventative maintenance such as those with batteries that are replaced infrequently are showing up with more electrical system issues, including the need to “Inspect and Repair Battery & Charging System.” “Replace ABS Control Module” wasn’t in the top 100 last year. It is responsible for helping to ensure a vehicle’s anti-lock brake system is working properly. While ABS has been available for decades, it’s been only recently that vehicle manufacturers made it standard on a wider range of vehicles and linked to the OBD2 system, which may explain its rapid trip upward in the list.  Click here for: The top 25 most common “check engine” vehicle repairs in the U.S. – 2011 (see tab – Index Data).

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

With this second annual release of the CarMD Vehicle Health Index, for the first time ever consumers, media and industry analysts can begin to compare year-over-year car maintenance and repair trends and patterns.

Source:  CarMD.com Corporation,  2012 Vehicle Health Index – April 2012 Update