CarMD Dash

If your car’s “Check Engine” light is on, chances are it won’t cost much to fix whatever’s wrong. CarMD, an automotive diagnostics company has been compiling data from their customers for years and it turns out most reasons for that warning light are rather easy fixes.

Beginning in 1996, the federal government mandated on-board diagnostics (OBD) for all passenger cars sold in the United States. The technology is universal and its primary function is to detect problems and set a computer code to assist repair shops in finding and fixing those problems. The OBD system does this by generating a diagnostic trouble code and turns the vehicle’s check engine light on if there a problem. 85 percent of all cars on the road have the OBD system.

CarMD sells a hand held diagnostic tool that reads those codes; it costs about $120. The CarMD tool helps motorists find out what’s wrong with their car by plugging into their car’s data port then into a home computer, accessing common problems and codes. As a result, CarMD has a large database of diagnostic trouble codes and now they’re releasing some of that information.

From 1996-2009 the most common reason for the “Check Engine” light illuminating was a loose or damaged gas cap. The fix for this can range from nothing to about $25 for a new gas cap. But this year, the most common reason for that telltale instrument panel light is a faulty oxygen sensor pushing the gas cap to second place. The oxygen sensor measures a vehicle’s exhaust and tells the engine if there’s too much or too little fuel being burned. The average cost to replace the O2 sensor is only about $200 but ignoring this problem can reduced fuel economy by up to 40 percent.

The third most common reason for the “Check Engine” light coming on is a bad catalytic converter. This one’s not so cheap; it costs an average of $2,000.

The fourth most common reason the “Check Engine” light comes on is due to a problem with the mass airflow sensor (MAF). The MAF measures the amount of air flowing to the engine. According to CarMD a malfunctioning MAF may result in a lack of power, hesitation, surging during acceleration and lower MPG. It costs approximately $375 to fix. Spark plug problems are number five on the list and although the fix can range from $20 for a do-it-yourselfer to a few hundred at a shop, neglecting this one problem can result in catalytic converter damage and that’s the one thing on the list that’s somewhat expensive.

Finally, if you’re keeping your current car longer or are looking for a used car instead of a new car and are worried about repair costs, CarMD says repair costs are actually down. Compared to a high in 2006, repair costs are now 16 percent less expensive.

So if you’re looking for a good used car or just want to keep your current vehicle and that pesky “Check Engine” light is on, odds are it won’t cost much to fix whatever’s wrong.

author photo

Brian Moody has been an automotive writer and presenter for more than 10 years. He has contributed to such media outlets as CNBC, Fox Business, the Today show, Speed TV, Edmunds.com and KTLA in Los Angeles. He currently covers the automotive industry and reviews new cars for the nationally syndicated Car Concerns radio show.

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