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CarMD has compiled the industry's most comprehensive database of diagnostic trouble codes and repairs for "check engine"- related problems downloaded by automotive technicians and vehicle owners since 1996. The data for the 2014 CarMD® Vehicle Health Index™ Manufacturer & Vehicle Rankings was procured from CarMD's network of thousands of independent and original equipment Automotive Service Excellence (ASE)-certified technicians who have input and validated failures and fixes into the CarMD diagnostic database.


The 2013 Index statistically analyzes more than 40,400 specific repairs that apply to roughly 88 million model year 2004 to 2014 vehicles, taking place in the United States during the Oct. 1, 2013 to Sept. 30, 2014 date period. The data for the 2014 CarMD® Vehicle Health Index was pulled, analyzed and validated between Oct. 1, 2014 and Nov. 3, 2014, by CarMD's internal team. The Index is based on downloaded information from each vehicle's government-mandated onboard diagnostic computer, combined with uploaded repair information from CarMD's network of automotive technicians. Repair costs are based on original equipment retail MSRP plus 10% markup. Labor rates are procured from several sources, including the Undercar Digest National and Regional Hourly Shop Labor Rate reports, as well as the average amount of time required for each repair. Both are updated annually.


For the 2014 Vehicle Health Index, CarMD focused on model year 2004-2014 vehicles, since the average age of a vehicle is now 11 years old, and these are the vehicles that will be of interest to new and used car buyers. In determining the Top 10 manufacturers and Top 100 vehicles, CarMD included all makes and models that were listed among the U.S. vehicle population, according to R.L. Polk data, and had a visit or repair logged by a member of CarMD's professional repair technicians. In determining the Top 10 manufacturers, brands were grouped under their parent manufacturer (i.e. Lexus and Scion under Toyota; Acura under Honda; Buick, Chevrolet, Cadillac, GMC, Hummer, Oldsmobile, Pontiac and Saturn under GM; Audi under Volkswagen; etc.) The data in the Index is applicable to roughly 85 percent of the vehicles on the road, giving a unique perspective on vehicles driven and repaired in the U.S. In determining the most common repairs by manufacturer, this Index looked at the entire OBD2 vehicle population (1996-current) vehicles for each manufacturer from Oct. 1, 2013 - Sept. 30, 2014.


CarMD contracted with a third party web-based project management company to program a formula that factored in the number of registered vehicles on the road for each manufacturer, make, model and year. A CarMD Vehicle Health Index rating was then assigned using the total number of red reports (or failures) per vehicle (or manufacturer) divided by the total number of vehicles in the population. Percentage of problems and average repair costs have been equally weighted in the CarMD Overall Index rating. The overall Index ranking for the Top Ranked Manufacturers and Vehicles were derived by the average of the Index and cost ranking and reliability scores.


On a daily basis, CarMD's nationwide network of thousands of factory-trained OE (original equipment) and independent automotive repair technicians recommend, confirm and upload repairs and costs by region to the CarMD database. As a result, subsequent CarMD Vehicle Health Index reports will draw from a larger sampling of diagnostic trouble codes, expert fixes and repair costs.