Why the "Check Engine" Light Comes On:
* Diagnostic Trouble Codes (DTCs): The light is triggered by the car's onboard computer (Engine Control Unit - ECU) detecting a problem or malfunction. It stores codes related to the issue, which can help diagnose the problem.
* Common Causes:
* Oxygen Sensor: Measures the amount of oxygen in the exhaust, a faulty sensor can cause fuel inefficiency and emissions issues.
* Mass Airflow Sensor (MAF): Measures the amount of air entering the engine, a faulty sensor can disrupt the fuel/air mixture.
* Catalytic Converter: Reduces harmful emissions, a damaged converter can cause engine performance issues.
* Spark Plugs and Wires: Faulty spark plugs or wires can cause misfires and poor engine performance.
* Evaporative Emission System (EVAP): Handles fuel vapors, a leak can cause a "Check Engine" light.
* Loose Gas Cap: A simple, yet common cause, can trigger the light.
What to Do When the "Check Engine" Light Comes On:
1. Don't Panic: While it's important to address the issue, it's not an immediate emergency.
2. Get the Codes Read: Take your car to a mechanic or use an OBD-II scanner (available at auto parts stores) to read the stored DTCs. This will give you a starting point for diagnosis.
3. Address the Issue: The specific repair needed will depend on the DTCs.
4. Don't Ignore It: Driving with the light on can lead to:
* Reduced Fuel Efficiency
* Engine Damage
* Increased Emissions
Tips for Avoiding "Check Engine" Lights:
* Regular Maintenance: Stay on top of oil changes, air filter replacements, and spark plug replacements.
* Gas Cap Tightness: Ensure the gas cap is securely fastened after filling up.
* Use Quality Fuel: Low-quality fuel can contribute to engine problems.
Important Note: Always consult a qualified mechanic for proper diagnosis and repair of any "Check Engine" light issue.
