The most anxiety-inducing warning light that can come on your dashboard is the check engine light. The check engine warning is so feared because of how ambiguous it can be. It can come on for a number of reasons, all ranging in severity. When this light comes on, it is important for you to bring your car to an auto repair shop for engine diagnostics. Below are 5 common reasons for a lit check engine light.   #1: Loose, Broken, or Damaged Gas Lid This problem is the cheapest and easiest to fix. When your light comes on, you should first check the gas cap. When your gas lid is damaged or not fastened, the gasoline in the tank can evaporate. Your car’s computer will catch this and trigger the light to come on.   #2: Failing Oxygen Sensor The O2 sensor is a part of your vehicle’s exhaust system, and it is in charge of measuring oxygen levels. It sends the info to your car computer and uses it to calculate a balanced air to fuel mixture.   #3: Malfunctioning Mass Air Flow Sensor The mass airflow sensor helps to perfect the spark ignition process by measuring and allowing air into the engine. When the MAF sensor is failing, it can lead to engine stalling, rough idling, poor fuel economy, and more.   #4: Worn Out Spark Plugs Without working spark plugs, the ignition process won’t kick-off. Spark plugs wear out over time. They reshape and get clogged. You may experience trouble starting the engine as a result.   #5: Clogged Catalytic Converter If your car starts to have a funky rotten egg smell to it, it means that your catalytic converter is the issue. The smell is a result of your catalytic converter not being able to change the engine’s toxic byproducts. When the catalytic converter fails to do its job, it will trigger the check engine light.   If you are looking for check engine light diagnostics and repairs, please do not hesitate to bring your car to Rainier Automotive. We can have your repairs done in no time. Please call or schedule an appointment using our online form today.