A check engine light is one of the most worrying—and, unfortunately, vague—indicators of vehicle trouble. The check engine light may illuminate for many reasons, necessitating a professional diagnostic performed by an experienced auto repair specialist. If you’re experiencing a check engine light in San Ramon, Walt’s Danville Service can help you diagnose the problem to get you back on the road safely and quickly.


The check engine light will illuminate to indicate any type of problem with your car’s engine or emissions system. Because this indicator is vague, taking your car to an auto repair shop is necessary to determine the cause of your check engine light and the best solution.

  • Dirty Oxygen Sensor: Your engine’s oxygen sensors help determine the amount of fuel burned inside the engine. These sensors become covered with oil residue over time, affecting their readings. A dirty or faulty oxygen sensor will decrease gas mileage while increasing your car’s emissions. An auto repair specialist can replace your sensor quickly and easily to eliminate your check engine light and restore proper fuel consumption monitoring.
  • Damaged Mass Airflow Sensor: Mass airflow sensors monitor the air flowing through your engine to determine how much fuel is required. A damaged or dirty mass airflow sensor can reduce gas mileage, increase emissions, and even cause your car to stall. Your auto repair shop can replace the mass airflow sensor to prevent engine damage and restore proper fuel intake and emissions.
  • Loose Fuel Cap: One of the simplest—and most easily addressed—causes of a check engine light is a loose fuel cap. Because the fuel cap plays an important role in your engine’s function, a loose, cracked, or otherwise faulty fuel cap can affect your entire fuel system. If your check engine light illuminates, try tightening your fuel cap and check it for cracks and wear.


Unsure what the light on your dash indicates? Check this list for a quick description of other warning lights your vehicle displays:

  • ABS: The anti-lock brake system, keeps your car from skidding when breaking. When lit, it indicates there is an issue with the and needs professional attention.
  • BAS: The brake assist system increases brake pressure in emergencies and works with the ESP (see below). Your brakes will still work, but if it stays on should be seen by a professional as soon as possible.
  • Battery: When your battery light is illuminated, the voltage level is below normal and the vehicle’s charging system is not working properly.
  • SAS/SRS: This light means there is an issue with your supplemental restraint system (airbag system) in your car.
  • ESP: This indicates there is a problem with the electronic stability system, which improves your vehicle’s stability through traction control by detecting and reducing skidding