The Five Most Common Causes Of The Check Engine Light

When you or I see the check engine light on our dashboard display, we should recognize that light as a call to action. The check engine light might be a signal of an inexpensive repair that you can perform yourself or it may alert you to a situation that could become dangerous if ignored. Many people may notice the dashboard light without understanding its significance. It’s my intention today to explain some of the most common reasons for the light to come on. Hopefully, you will also become committed to responding quickly the next time you see the check engine light in your car, van or truck.

Cause Number 1: The oxygen sensor or mass air-flow sensor is providing faulty information.

The job of the oxygen sensor is to detect how much unburned oxygen is in the exhaust and to share that information with the computer. The information is used to determine the amount of fuel left in the gas tank. If the oxygen sensor isn’t working correctly, then you are probably getting less efficient gas mileage from your car. This will end up costing a lot more than the price of having the sensor repaired.

The mass air-flow sensor performs a function similar to that of the oxygen sensor. Instead of measuring unburned oxygen, however, the mass air-flow sensor measures how much air is getting to the engine. The car is then able to regulate the amount of fuel to be used. As with problems with the oxygen sensor, the result of neglecting this repair will lead to decreased power and fuel efficiency. This repair is also much less expensive than the additional costs of gas you’ll be paying for at the pump.


Cause Number 2: Your gas cap is loose or missing.

You may be able to resolve this issue yourself. Gas caps are easy to come by and are relatively inexpensive. Many gas stations even have a collection of gas caps that have been left behind by other car owners. However, if you replace your gas cap with a cap for a different make or model of a car, then you might still suffer from a loose cap. The loose or missing cap will allow your gas to evaporate. I don’t know about you, but when I pay those high prices at the pump, I want to know that every drop of gas is put to good use.

Cause Number 3: The catalytic converter is broken.

This very expensive repair can usually be prevented by your routine maintenance. However, if spark plugs or other related parts are damaged or faulty, then the catalytic converter may be affected. The catalytic converter is basically used to reduce the amount of harm caused by the emissions of your vehicle. The catalyst is typically a precious metal, thus the high price of repairs. Don’t feel tempted to skimp on these repairs, though. Talk to a trusted mechanic to see what can be done for your car.

Cause Number 4: The distributor is defective.

If you find that the check engine light is on because of trouble with your distributor, then you need to respond quickly. The faulty distributor can lead to your car suddenly dying when it becomes hot. Sometimes your car won’t start at all. A faulty distributor could involve a wide number of automotive problems. You may have the ability to check through the ignition coil, the distributor, the igniter and the module yourself. If so, be sure to check them in that order. If you still haven’t found the source of the problem, then you can also look through the grounds, resistors, power in and out sensors and other related parts. Otherwise, take this problem to your mechanic.

Cause Number 5: Your spark plugs aren’t firing correctly.

This is my personal favorite. Spark plugs are fairly easy to replace and by replacing them yourself you can save a substantial amount of money. Each spark plug creates a miniature explosion inside the internal combustion engine. The spark plug causes a spark which ignites the pressurized fuel, leading to a pumping action inside the engine. Spark plugs could become worn out or damaged due to normal use of your car. If your spark plugs aren’t firing correctly, you will once again experience less power and fuel efficiency. Ignoring a malfunctioning spark plug can become very costly. The errant spark plug could end up causing damage to the catalytic converter.


In many cases, routine preventative maintenance can help you to avoid a host of problems. However, over time most engines will have some type of trouble. As soon as you see the check engine light, be aware that there is an issue to be addressed and then act promptly.

Posted by on November 29, 2012. Filed under Auto. You can follow any responses to this entry through the RSS 2.0. Both comments and pings are currently closed.