While hybrid cars have been on U.S. roads in large numbers for over a decade, their reliability and repair costs may still spook some potential buyers.

The innards of a modern car are already mysterious enough for the average person; add in extra electrical components and things get even more confusing.

Yet a new repair-cost study shows some encouraging results for hybrid owners.

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Average repair costs for hybrids  went down this year, even as they stayed the same for types of cars, according to the 2015 CarMD Vehicle Health Index.

CarMD maintains a nationwide network of technicians, which it leverages to build and maintain a database of car problems and fixes.

The 2015 Vehicle Health Index drew conclusions from 90,051 car repairs that took place in the U.S. in 2014.

2001 Honda Insight

2001 Honda Insight

Researchers found that average hybrid repair costs fell from 2013 to 2014--the fifth year in a row in which costs dropped.

One of the more costly repairs for a hybrid--replacing an inverter assembly--dropped a massive 51 percent between 2013 and 2014.

The 2014 cost was $1,357, compared to $2,800 for 2013. That's the fourth straight year the cost of this repair has decreased.

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It wasn't all good news, though.

The cost of another expensive component--a replacement battery pack--rose to an average $3,479 in 2014, up 11 percent from 2013's $3,140.

Meanwhile, repair costs for non-hybrid cars remained essentially flat, climbing 0.6 percent between 2013 and 2014.

2008 Ford Escape Hybrid

2008 Ford Escape Hybrid

Overall, the most common problem listed was "replace oxygen sensor" although--at an average $259--it was far from the most expensive.

The second most common problem was the need for a new catalytic converter--which cost an average $1,150.

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The most expensive region of the country for repairs was the West, where owners paid an average $423 for repairs stemming from a check engine light.

It's also the region that includes the state with the most hybrids--California.

The cheapest part of the country was the Midwest, with an average $375 cost for similar repairs.


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