Sign In

Why Does Your Check Engine Light Turn On?

Last updated 6 years ago

One clear sign that your car needs maintenance or repairs is the activation of the check engine light. Most people don’t know what sort of problems will make the light turn on. This warning is known in the automotive industry as the Malfunction Indicator Light (MIL). The MIL is connected to your car’s computer, which activates the light when one or more of its sensors are triggered. Here is a quick look at some common reasons for seeing the check engine light:

  • Loose Gas Cap- A loose gas cap is an incredibly common reason for the check engine light to turn on. This means that the cap for your fuel tank is loose or missing. This allows your fuel to evaporate quickly and reduce your perceived gas mileage.
  • Bad Spark Plugs- Spark plugs are used to ignite the mixture of gas and air in your engine, producing the combustion that powers your car. If a spark plug is broken, the gasoline inside the combustion chamber, will not combust. This can cause serious damage to the entire exhaust system. Do you need new spark plugs? Feel free to contact A1 Auto Tech in Mountain View.
  • Faulty Oxygen Sensor- When your car’s oxygen sensor fails, it registers the wrong information about the amount of unused gasoline coming through the exhaust system. This can alter the air-to-gas ratio and make the vehicle less efficient. A faulty oxygen sensor could make a bad spark plug difficult to detect, opening the opportunity for expensive exhaust damage.
  • Clogged Exhaust System- Another problem that might activate the check engine light is a clog in the exhaust system. A serious clog could cause back pressure, reducing the engine’s power and efficiency. Back pressure problems can become very serious in a short period of time, so it is important to pay attention to the MIL (aka: Check Engine Light).

If your check engine light is glowing on your dash, then come to A-1 Auto Tech, Inc. in Mountain View, California. We would be happy to inspect your American or Japanese made vehicle. We provide excellent service, parts, and maintenance for all of your automotive needs. For more information, call (650) 265-4085 or contact us online.


  • Loading comments... Spinner

  • Hours:

  • 7:00 AM to 5:30 PM Monday
  • 7:00 AM to 5:30 PM Tuesday
  • 7:00 AM to 5:30 PM Wednesday
  • 7:00 AM to 5:30 PM Thursday
  • 7:00 AM to 5:30 PM Friday


  • Recent Posts
    • Loading posts... Spinner
  • View All
  • Recent Comments
    • Loading comments... Spinner
  • Related Links
  • Popular Tags
    • Loading tags... Spinner