Top 5 Common Causes of a Check Engine Light
It’s never a good feeling when the little engine icon lights up on your car’s dashboard. To make the problem worse, it’s incredibly uninformative. There can be any number of reason why the light doesn’t give you any details, and diving into the owner’s manual is of no help at all.
Fortunately, we can rely on statistics to get a fairly ballpark idea of what the problem might be. These are the top five common causes of a check engine light:
Failing Oxygen Sensor
A faulty oxygen sensor will cause your car’s computer to get confused about just how much fuel it is burning. That can lead to a significant drop in fuel economy—as much as 40 percent!—and an increase in emissions. Fixing this will cost around $200, but you absolutely want to get it done; if you don’t, you’ll most likely bust your catalytic converter, and that can cost upward of $2,000. Save yourself the trouble.
Loose Fuel Cap
The check engine light may come on if your gas cap is loose, allowing gas to evaporate. This also reduces gas mileage and increases emissions, but fortunately, fixing this may not cost you any more than $3.
Failing Catalytic Converter
This is one of the most troublesome problems and can unfortunately cost quite a lot to repair. The catalytic converter is responsible for converting harmful gases and materials into harmless compounds. If it fails, you’ll notice lower fuel economy and that the car struggles to go any faster when you push on the gas.
The upside is that if you’ve been properly maintaining your car, it’s highly unlikely that the catalytic converter will fail, which it mostly commonly does because of a faulty spark plug or oxygen sensor. The downside is that if it actually is the reason behind your check engine light, you can generally assume there are other underlying problems that have caused it to fail.
Bad Spark Plugs and Wires
If you notice the engine has been misfiring, this is probably the reason. You can save a lot of money by fixing this yourself, as spark plugs can cost a mere $5-$10 apiece and it’s no hassle at all to replace them. Ignoring it will again lead to worse fuel economy and permanent damage to the catalytic converter.
Malfunctioning Mass Air Flow Sensor
This sensor is responsible for measuring the air in the engine and calculating how much fuel to inject. If it malfunctions, you’ll see a drop in fuel economy by as much as 25 percent. You can prevent this problem by changing your air filters (for about $25). An air flow sensor costs about $300.