6 Reasons Why The Check Engine Light May Come On
Here are the six common reasons that can trigger the check engine light of your vehicle:
1. Failed Oxygen Sensor
An oxygen sensor measures the unburnt oxygen in your vehicle’s exhaust system. This helps the ECM (car’s computer) to know how efficiently the fuel burns during combustion. Accordingly, the ECM creates an ideal air fuel mixture to offer optimum mileage under different driving conditions.
However, these sensors have to tolerate extremely high temperatures and are prone to fail when your vehicle crosses 80,000 miles.
A faulty oxygen sensor can even damage your spark plugs and catalytic converter, leading to costly repairs. Your vehicle will also not pass the emission tests as a bad catalytic converter will emit harmful compounds like hydrocarbons and nitrogen oxides.
2. Loose Gas Cap
Sometimes, an issue as simple as a loose gas cap can cause the diagnostic system to turn on the engine light.
Your gas cap is a part of a sealed evaporative emissions system that prevents the gas vapors from escaping into the air.
If you accidentally leave this gas cap loose, you can lose fuel through evaporation, and your exhaust gas recirculation system will not function smoothly.
3. Weak Car Battery
When your car battery is weak or isn’t fully charged, it’ll fail to send enough power to your vehicle’s ECM. This will result in a flashing check engine light, and your ECM will register a trouble code.
You may also notice an illuminated battery light on your dashboard, indicating an issue with your battery or alternator. When that happens, you should call your service center and schedule a battery service.
4. Faulty Spark Plugs
Spark plugs are responsible for generating an electric spark to crank your engine. When the spark plugs are worn out, they can lead to ignition problems, fuel wastage, and even damage other essential elements of your vehicle.
Worn-out spark plug wires can also cause the check engine light to come on. In other cases, it could be the ignition coil that’s to be blamed.
5. Faulty Mass Airflow Sensor
The mass airflow sensor in your vehicle measures how much air enters the engine. The ECM uses this data to determine the amount of fuel to inject into the combustion chamber.
If the sensor goes bad or there are any leaks in the air intake tract, the check engine light will come on.
The mass airflow sensor is also sensitive to dirt, water, and oil. So, contamination in the air tract can trigger the check engine signal too.
6. Engine Misfires
Spark plugs help ignite the air and fuel mixture in the combustion chamber. If the timing of the spark is off or if the fuel mixture and its compression isn’t right, your vehicle can misfire.
Some other reasons that could also cause engine misfire and trigger the engine light are:
- A defective ignition coil
- Worn spark plugs and plug wires
- A defective fuel injector
If you keep ignoring the check engine light for such misfires, they can result in serious problems like a mechanical failure of your car’s engine.