When your check engine light is blinking, it’s hard not to panic. Somehow, it always seems to happen at the worst possible time. What does it mean? Is your car on the verge of breaking down? Will you be able to drive yourself to a mechanic to get it checked out? There are several reasons why your check engine light might be on, and the good news is that they’re not always catastrophic.
1. Bad Spark Plugs
Today, cars are manufactured with better spark plugs than in the past, which means they’ll typically last for 100,000 miles before needing replacement. If you’ve reached the 100K mile mark, have an older car, or have a newer model that’s an unfortunate outlier, your blinking check engine light might just mean it’s time to replace your spark plugs. This is especially true if your car has been stalling, performing badly, having rough idling, or reduced fuel efficiency. If you have experience working on cars, you may be able to replace the spark plugs on your own, but if not, take your car to an auto repair shop.
2. Loose Fuel Cap
This one certainly isn’t catastrophic—in fact, it’s probably the best case scenario when your check engine light is blinking! Sometimes a gas cap that’s loose, missing, or broken can cause your vehicle’s systems to give you a false alarm, as a loose fuel cap can lead to some of the same issues caused by a fuel line leak or other engine problems, like air in the gas tank or vapors escaping. If your check engine light is on and your car has no other signs of trouble, make sure you check your gas cap before heading to a mechanic.
3. Failed Catalytic Converter
When a catalytic converter fails, you’ll usually have many more signs that something is seriously wrong with your vehicle. If it’s feeling sluggish and having trouble accelerating or your exhaust is suddenly black and has a foul odor, you likely have a bad catalytic converter. This has the potential to be dangerous because the black smoke your car is emitting can have high levels of carbon monoxide. Unfortunately, replacing a catalytic converter can be costly, so if your car is an older model, you may fare better by simply buying a new car.
4. Broken Oxygen Sensor
The oxygen sensor—also known as an O2 sensor—monitors the level of oxygen and unburned fuel that is exhausted by your car. When this is malfunctioning or broken, it will cause your check engine light to blink. While this is not necessarily an emergency, if you don’t get your oxygen sensor replaced in a timely manner, you can damage your catalytic converter and reduce your vehicle’s fuel efficiency.
5. Malfunctioning Airflow Sensor
A malfunctioning airflow sensor is much like a broken oxygen sensor—it will cause your check engine light to turn on, but it’s not necessarily a crisis situation that requires immediate repair. You’ll notice that you get fewer miles per gallon and performance is not optimal, but you have time to schedule an appointment with an auto repair shop to get it taken care of.