The check engine light is part of your vehicle’s onboard diagnostics (OBD) system. When it illuminates, it means a sensor has detected a problem in the engine, transmission, or emissions system. The issue could be simple, or it could be a sign of something more serious. Ignoring it is never a good idea.
Common Reasons Your Check Engine Light is On
While the possibilities are vast, some issues are more common than others. Here are a few of the most frequent culprits:- A Loose or Faulty Gas Cap: This is the simplest fix. A loose gas cap can break the seal of the fuel system, which triggers the light. Always try tightening it first. If the light doesn’t go off after a few trips, you may need a new cap.
- Worn Spark Plugs or Wires: Spark plugs are essential for igniting the fuel in your engine. If they’re failing, you might notice poor acceleration and reduced fuel economy.
- Failing Oxygen (O2) Sensor: This sensor measures the amount of unburned oxygen in your exhaust system. A faulty sensor can’t provide the right data to the engine’s computer, leading to decreased fuel efficiency and increased emissions.
- Mass Airflow Sensor Failure: This sensor tells your car’s computer how much air is entering the engine. If it fails, it can damage spark plugs, O2 sensors, and even your catalytic converter.
- Damaged Catalytic Converter: This is a more serious and expensive repair. The catalytic converter turns harmful carbon monoxide into less harmful emissions. If it’s failing, your car will not pass an emissions test and will run poorly.