Check a VIN

How we rate cars and model years

Every figure on KnownFlaws is calculated the same way for every car. This page explains where the data comes from, how each verdict and score is worked out, and what the data cannot tell you.

Where the data comes from

All complaints, recalls, defect investigations and technical service bulletins come from official public vehicle safety records published by the US government. We download the full records every day and rebuild the site from them.

Complaints are filed by vehicle owners themselves. We publish their text unedited, but we remove anything that could identify a person: names, cities, VINs and dealers are never shown.

Fuel economy and crash test figures come from official public government data as well. KnownFlaws is independent and is not affiliated with any automaker or government agency.

How we count complaints

Each complaint is counted once for the make, model and model year it was filed against. A complaint can mention several systems (for example the engine and the electrical system), so it can appear under more than one problem category, but it is only counted once in the total for that car and year.

Problem categories group the official component names into the terms people actually search for, such as transmission, engine, electrical or brakes.

Years to avoid

For each model we take the typical number of complaints per model year: the median of the model years from the last 25 years that have been on the road for at least three years.

A model year is flagged as a year to avoid when it has at least twice that typical number of complaints (and at least 50 complaints). Older model years are not flagged, because few owners filed complaints online back then.

Best years

The best years of a model are the three model years with the fewest complaints among the last 20 model years, counting only years that have been on the road for at least four years, because newer cars have had less time to fail. Years flagged to avoid are never listed as best years.

The year score (0 to 100)

Each model year gets a score from 0 to 100 that compares it with the other model years of the same car. A typical year scores 75. Every time the complaints double, the score drops by 25 points: twice the typical complaints scores 50, four times scores 25. Years with fewer complaints than usual score higher, up to 97.

The score also drops by up to 10 points when a year has a higher share of serious complaints (crashes, fires, injuries and deaths) than the model as a whole, and by up to 6 points when it has more than two recalls.

Model years with less than four years on the road, years older than 25 years and models with very few complaints per year get no score. The score compares years of the same car, not different cars: a 75 on one model is not the same as a 75 on another.

Symptoms

Symptoms such as transmission shudder, oil consumption or phantom braking are found by reading the text of every complaint for words and phrases that describe them, whichever category the owner picked. A complaint can describe more than one symptom.

Repair costs

Repair costs are the median of the dollar amounts owners wrote in their complaints about a given problem. They are only shown when enough owners mentioned a price, and they reflect what those owners paid, not a quote for your car.

What the data cannot tell you

Complaints are unverified statements by owners. A high count can reflect how many cars were sold as much as how reliable they are, which is why we compare model years of the same car rather than different cars.

A recall or service bulletin may already have fixed a problem on a specific car. Before you buy, check that car's open recalls with its VIN and have it inspected by a mechanic you trust.

Updates

The data is refreshed every day. Counts, verdicts and scores can change as new complaints arrive, especially for recent model years.