The check engine light, often referred to as the "service engine soon" light or the "malfunction indicator lamp" (MIL), is a signal from the car's engine computer that something is wrong. Here's what you need to know about this important dashboard indicator:

Purpose of the Check Engine Light

The check engine light is part of your vehicle’s onboard diagnostics system (OBD-II), which monitors the performance of the engine and other vital components. When the OBD-II system detects a problem that could affect the vehicle’s emissions, performance, or safety, it triggers the check engine light to alert the driver.

Common Reasons for the Check Engine Light to Activate

  1. Oxygen Sensor Failure: The oxygen sensor measures the amount of unburned oxygen in the vehicle's exhaust and helps manage fuel efficiency. A failure can lead to a poorly running engine and decreased gas mileage.

  2. Loose or Faulty Gas Cap: A loose or damaged gas cap can cause fuel vapors to leak out, affecting the fuel system pressure and increasing emissions.

  3. Catalytic Converter Issues: The catalytic converter helps protect the environment by converting harmful carbon monoxide into carbon dioxide. Failure can lead to reduced performance and fuel economy, and the vehicle might not pass an emissions test.

  4. Mass Airflow Sensor Malfunction: This sensor measures the amount of air entering the engine, which is crucial for the onboard computer to balance and deliver the correct fuel amount to the engine. A malfunction can lead to engine stalls, trouble starting, and increased emissions.

  5. Ignition System Defects: Problems with the ignition system, such as failing spark plugs or ignition coils, can cause the engine to misfire and trigger the check engine light.

What to Do When the Check Engine Light Comes On

  • Check the Gas Cap: First, ensure the gas cap is tight and in good condition as this is a simple fix.

  • Use an OBD-II Scanner: To find out exactly what's wrong, you can use an OBD-II scanner to read the codes stored by the car's computer, or have a mechanic do this.

  • Assess the Urgency: If the light is steady, it suggests a less urgent issue, but you should still have the car checked soon. If the light is flashing, this indicates a more serious problem, such as a misfire that is dumping unburned fuel into the exhaust system, and the car should be inspected immediately to avoid damage.

Diagnostic and Repair

Once a mechanic reads the error code, they can perform further diagnostics to isolate the exact cause of the problem. Repair options can range from simple fixes like replacing the gas cap or oxygen sensor to more extensive repairs like replacing the catalytic converter or repairing the fuel injection system.

Regular maintenance and addressing check engine light warnings promptly can help prevent more severe problems and extend the life of your car. If you’re unsure about the severity of the issue when your check engine light comes on, it's generally wise to consult a professional mechanic as soon as possible.

Baber Auto Repair is an independent, family-owned repair shop with ASE Certified Technicians who live in the neighborhood. We are located in Roseville, MN and we service vehicles from all over the St. Paul/Minneapolis area. Our customers come from all over – including Falcon Heights, Arden Hills, Little Canada, and Vadnais Heights. If you feel like your vehicle’s Check Engine Light is something you need serviced or repaired by reliable mechanics, contact us today!