Check engine light on? What it means and how to fix it

Last updated: January 1

So, you're driving along and suddenly, the check engine light comes on. This can bring several questions to mind. Should you stop driving immediately? What's wrong? Is it serious? Do you need to call a tow truck? How much will this cost?

quality auto coverage starts here

When you drive with quality coverage, you drive with peace of mind. Allstate auto insurance can help you stay protected for wherever the road takes you.

What the check engine light means

A vehicle's check engine light can turn on for many reasons, ranging from a minor issue to a serious problem. Before trying to troubleshoot the problem, keep in mind what the check engine list is signifying. As Consumer Reports points out, the check engine light means that the vehicle's electronic control system has identified a problem that it can't correct automatically.

After the light is triggered, a trouble code is stored in the computer's memory to properly identify the issue. This code can be read by a diagnostic tool carried by most auto repair shops. A qualified mechanic can read the code, diagnose the problem and repair your vehicle.

According to, some manufacturers and vehicle models have different warning lights to indicate the severity of the problem. The check engine light may either blink or remain constant.

If the light is steady, it may not be an emergency, but you should get the problem checked out by a mechanic as soon as possible. However, a blinking light usually indicates a severe engine misfire, which allows unburned fuel to be dumped into the exhaust system. This can cause extensive damage and result in costly repair bills.

Common causes

The Family Handyman has compiled a list of common causes of a check engine light. These include:

  • Loose, damaged or missing gas cap.
  • Failed or failing O2 sensors.
  • Spark plug, wiring or ignition issues.
  • Catalytic converter failure.

What to do if you're driving

Once your check engine light goes on, Consumer Reports identifies a few things you can do if you're driving when the light appears. First, you can check your dashboard gauges and lights to see if there's a low oil pressure warning or if your engine is overheating. If you find any of these problems, it's best to pull over as soon as it's safe to do so. These problems can be serious and create a dangerous situation for yourself and your vehicle.

Also, if you notice performance issues with your vehicle, it's a good idea to reduce your speed and the demands on your engine.

Since the check engine light can point to any number of issues, it's a good idea to have a qualified mechanic diagnose the issue as quickly as possible. That way they can fix the problem and get you safely back on the road.