Consumer Reports explains what the check engine light means and what to do when you see it: how to tell if your car has a loose gas cap—or a serious engine problem.

CarMD, an automotive telematics company, published a list of the most common check engine codes in 2020, along with their estimated cost of repair.

If your vehicle is throwing a check engine light, but you don't have a diagnostic scanner handy, here are three tricks to try before seeing a mechanic.

CarMD, an automotive telematics company, published a list of the most common check engine codes in 2020, along with their estimated cost of repair.

In 2018 the two most common check engine repair codes were "replace ignition coil (s) and spark plug (s)" and "replace oxygen sensor" — each accounting for 5.8 percent of repairs.

While "Check Engine" and "Service Engine Soon" may sound like they indicate the same issues, they're actually for two different types of problems.

Drivers of affected cars may also see a "check engine" light. "Fuel pump failure is more likely to occur under low fuel or warm weather and hot fuel conditions in the fuel tank," Ford noted.