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Why Is My Check Engine Light On?

If you're cruising on the road and the check engine light comes on, you'll most likely notice it right away. Dashboard lights have been around for a while, and they serve to alert you when something goes wrong with your vehicle's health. For example, some symbols can tell you if your tire pressure is too low or when your engine runs too hot. However, the check engine light remains to be a warning that can mean many things. It can indicate a minor issue to something detrimental, so it is important for you to get a diagnosis immediately after it comes on.

Below are some common problems that may trigger your check engine light to illuminate:

Loose Gas Cap

If you just pulled away from the gas station and your light comes on, it is probably due to a gas cap that isn't completely secured. A gas cap that is loose or damaged in any way can turn your check engine light on. Gasoline can evaporate, so please tighten or replace your gas cap if necessary. Fortunately, gas caps are relatively the easiest, quickest, and most inexpensive fix. 

Filthy Oxygen Sensor

Your car's oxygen sensor, or O2 sensor, measures the amount of unburned oxygen released from the exhaust. It also plays a part in monitoring fuel consumption. Over time, the oxygen sensor can wear down or become caked with combustion elements. When it performs inadequately or does not perform at all, your check engine will come on.

Engine Overheating

If your car is overheating, you may notice your temperature gauge or smoking spewing from under the hood. In some scenarios, your check engine may also come on and blink. You should immediately pull over and turn on the heater to draw the heat away from the engine ASAP. Next, call for roadside assistance.

Poor Spark Plugs

The spark plugs provide the spark needed to ignite the gas for combustion. If the spark plugs are no longer active, it will lead to poor engine performance and misfire. Therefore, it will also switch the check engine signal on.

Clogged Catalytic Converter

The catalytic convertor works hard to minimize harmful emissions that your vehicle releases. It changes hazardous pollutants such as carbon monoxide and turns them into safer gasses like carbon dioxide. If the catalytic converter is not working, there are many hazards at hand. A damaged catalytic converter can hurt your fuel economy, increase emissions, and cause deadly gas leaks.


Don't let your check engine light shock you. If your check engine has just come on, please bring it to Bud's Auto Repair & Transmission right away.