Feb 2017
Check Engine Light

You have automotive warning lights on your cars dashboard. You're not sure what they mean. This blog will discuss what the Check Engine Light is, does, etc. If your vehicle has warning lights and you're not sure what to do, dont hesitate to visit A Auotcare for a FREE check engine light diagnosis.

Check Engine Light


Image of check engine light from a 1998 Honda


What does Check Engine Light symbol look like?

Image of common check engine lights icons

The most common visual sign will be an engine icon with or without “Check”, “Check Engine”, ”Service Engine Soon”, “Check Powertrain” on the vehicles instrument panel. It will be Amber or Red in color.


What is the Check Engine Light?

The Check Engine light is a vehicle’s warning system. This warning system is part of your vehicle's computer onboard diagnostics (OBD) system. According to wikipedia, OBD is an automotive term referring to a vehicle's self-diagnostic and reporting capability. In all cases it indicates a problem your emission system or engine system. ODB-I system is 1980's to 1995. Since 1996, motor vehicles have been equipped with OBD-II.

Image of screen from OBD2 hand scanner

Maintenance light is not the engine light!

Image of maintenance light.


Many people confuse their maintenance light with their check engine light. Your maintenance light refers to oil change or other regular service items. These lights illuminate when a routine service is due.

image of common maintenance lights not engine lights


What does the Check Engine Light do?

When a problem in you’re your car is bad enough the check engine light illuminates. It will either blink or remain constant, depending on the problem. The car also stores a trouble code in it's computer memory. These trouble codes help you identify the probable source of the problem.

Image of random engine misfire trouble code


Why is the Check Engine light on?

The Check Engine Light can mean many different things, from a loose/broken gas cap to a serious mechanical problem.

Possible causes for the check engine light to be on

  1. Gas cap loose
  2. Catatyilic converter failing
  3. Engine misfire- spark plugs or coil failing
  4. Vacuum leak
  5. Mass air flow meter dirty/failing
  6. Oxygen senor(s) out of range/failing

My check engine light is on or flashing!

On vehicles equipped with OBD-II (Year 1996+ vehicles), the light has two stages:

  1. Indicator lamp is Steady: Minor fault. The problem is not an emergency, but you should schedule an appointment or diagnose asap. If the vehicle continues to operate normally and the driver cannot tell any difference in performance, it is most likely safe to finish the travel being taken. At earliest convenience schedule an appointment with local mechanic or diagnose yourself.
  2. Indicator lamp is Flashing: Severe fault. Continual driving could cause serious harm. If the vehicles performance is noticeably reduced or the engine seems to run “rough” or lacking power, the problem needs to be addressed ASAP to avoid the possibility of further damage. Pull over and have vehicle towed to local mechanic (A Autocare) or home. Schedule an appointment with local mechanic (A Autocare) or diagnose yourself.

For either stage, check your dashboard gauges and lights for signs of low oil pressure or overheating . These circumstances mean you should pull over and shut off the engine as soon as possible.


More info

In future blogs i will dive more into check engine light diagnosis,