The “check engine” light is part of your car’s so-called onboard diagnostics (OBD) system. Since the 1980s, computers increasingly have controlled and monitored vehicle performance, regulating such variables as engine speed (RPM), fuel mixture, and ignition timing. In some cars, the computer also tells the automatic transmission when to shift.

There are hundreds of codes that could trigger your CHECK ENGINE LIGHT for thousands of reasons. Even the most common reasons can have many other possible causes. Listed below are some of the top CHECK ENGINE LIGHT codes:

  • Problem with the Mass Air Flow (MAF) sensor or circuit.
  • System Running Too Lean.
  • System Running Too Rich.
  • Cylinder Misfire.
  • Knock Sensor Circuit Malfunction.
  • Insufficient EGR (Exhaust Gas Recirculation) Flow.
  • Catalyst System Efficiency below Threshold.

These are just a few of the hundreds of codes, causes and symptoms, each has multiple fixes.

What happens when I ignore the Check Engine Light or put off service?

A non-flashing Check Engine Light, is usually a less severe problem that should be checked as soon as possible.

A flashing Check Engine Light means your vehicle senses a critical system error (such as a major cylinder misfire ) & you need immediate attention before potentially breaking down and possibly damaging other critical & expensive parts. In this case, continuing to drive can lead to further damage rather quickly or can leave you stranded.

Modern vehicles come equipped with an onboard computer diagnostic system (OBD II) that monitors your vehicle’s operations. The OBD II system monitors emissions control systems. That means the monitors can detect anything from a loose fuel cap to a clogged catalytic converter.