“Many people fear that when the check engine light comes on, it is going to mean several hundred or more dollars in repairs, so they ignore the light and hope the problem goes away,” said Rich White, executive director, Car Care Council. “Data from CarMD makes it clear that not addressing the cause of an illuminated check engine light can cost you in terms of wasted fuel and more expensive repairs in the future.”

When the check engine light is illuminated, it usually means that the vehicle system, such as the ignition, fuel injection or emission control, is not operating properly, even if the vehicle appears to be running normally. The top 10 most common check engine light repairs as reported by the recently released CarMD Vehicle Health Index are as follows.

  1. Replace O2 sensor(s)
  2. Replace ignition coil(s) and spark plug(s)
  3. Replace catalytic converter
  4. Inspect fuel cap and tighten or replace as necessary
  5. Replace evaporative emissions (EVAP) purge control valve
  6. Replace mass airflow (MAF) sensor
  7. Replace ignition coil(s)
  8. Replace evaporative emissions (EVAP) purge solenoid
  9. Replace fuel injector(s)
  10. Replace thermostat

“Following a recommended maintenance schedule and addressing small problems before they become bigger ones will help extend the life of your car and minimize check engine-related repairs,” continued White. “It’s important to note that most of the common check engine problems negatively impact a car’s fuel economy and become more costly to repair if service is delayed.”