Check Engine Light On? Causes, Warning Signs & What to Do First

Few dashboard warnings cause more anxiety than the check engine light. It can pop on without warning, stay lit for days, or suddenly start flashing while you’re driving. But what does it actually mean, and how serious is it?

At Steve’s Imports, we help drivers every day with check-engine-light diagnostics and repairs. The good news? In many cases, the issue is manageable, especially if you address it early.

Let’s break down what your check engine light really means and what you should do first.

What Is the Check Engine Light?

Your check engine light (also called the malfunction indicator lamp) is part of your vehicle’s onboard diagnostic system. When your car’s computer detects a problem affecting the engine, emissions system, ignition, or fuel system, it turns the light on and stores a diagnostic trouble code.

The light doesn’t tell you exactly what’s wrong; it tells you that something needs attention.

Solid vs. Flashing Check Engine Light

What Your Check Engine Light Really Means (and What to Do First) OR

Not all check engine lights are the same.

Solid Check Engine Light

A solid (non-blinking) light typically indicates a non-emergency issue. Your vehicle may still drive normally, but something isn’t operating at peak efficiency.

Common causes include:

  • Loose or faulty gas cap
  • Failing oxygen sensor
  • Faulty mass airflow sensor
  • Worn spark plugs or ignition coils
  • Minor emissions system issues

You can usually continue driving short distances, but you should schedule a diagnostic service for the check engine light as soon as possible to prevent further damage.

Flashing (Blinking) Check Engine Light

A blinking check engine light is serious. It usually signals a severe engine misfire, which can quickly damage your catalytic converter, one of the most expensive components in your exhaust system.

If your check engine light is flashing:

  • Reduce speed immediately
  • Avoid heavy acceleration
  • Pull over safely if performance worsens
  • Schedule immediate engine repair

Driving for a long time with a flashing light can turn a manageable repair into a costly one.

The Most Common Reasons Your Check Engine Light Turns On

Here are some of the most frequent issues we diagnose at Steve’s Imports:

1. Loose or Damaged Gas Cap

This is one of the simplest causes. A loose gas cap allows fuel vapors to escape, triggering an emissions warning. Tighten it and drive a few trips to see if the light turns off.

2. Oxygen Sensor Failure

The oxygen sensor monitors fuel mixture efficiency. When it fails, your vehicle may burn more fuel and increase emissions.

3. Catalytic Converter Issues

If ignored for too long, other engine problems can damage your catalytic converter, leading to reduced performance and expensive repairs.

4. Spark Plug or Ignition Coil Problems

These components ignite the fuel-air mixture in your engine. When they wear out, you may experience rough idling, hesitation, or engine misfires.

5. Mass Airflow Sensor Problems

This sensor helps regulate fuel delivery. A faulty sensor can reduce fuel economy and engine performance.

What Should You Do First?

If your check engine light turns on:

  1. Check your gas cap – Make sure it’s tight.
  2. Pay attention to performance changes – Is the engine running rough? Is it harder to start?
  3. Look for other warning lights – Temperature or oil pressure warnings require immediate attention.
  4. Schedule a professional diagnostic scan – This is the fastest way to identify the exact issue.

At Steve’s Imports, our advanced diagnostic equipment allows us to quickly identify the trouble code and determine the correct repair, without guesswork.

Is It Safe to Keep Driving?

Here’s a quick rule of thumb:

  • Solid light, no performance issues: You can drive short-term, but schedule service soon.
  • Solid light + rough driving: Have it inspected within a day or two.
  • Flashing light: Stop driving and seek immediate repair.

Ignoring your check engine light can reduce fuel efficiency, increase emissions, and potentially cause serious engine damage.

Why Prompt Diagnostics Matter

Modern vehicles are complex. A small sensor failure today can lead to larger engine or exhaust system damage tomorrow. Early detection through professional check engine light diagnostics can:

  • Prevent costly repairs
  • Protect your catalytic converter
  • Improve fuel economy
  • Extend engine life
  • Keep your vehicle reliable

If you drive a European or Asian import, specialized knowledge and tools matter even more.

Contact Steve’s Imports

If your check engine light is on, don’t ignore it, and don’t panic.

Our experienced technicians provide accurate diagnostics and honest repair recommendations to get you safely back on the road. Call today to schedule your check engine light diagnostic service. We’re here to help you drive with confidence.

Check Engine Light FAQs

How much does a check engine light diagnostic cost?
Diagnostic costs vary depending on the vehicle and issue. Contact us for current pricing and availability.
Will the check engine light turn off by itself?
Sometimes — especially if it was triggered by a loose gas cap. However, if the underlying issue remains, the light will return.
Can I pass emissions with my check engine light on?
In most cases, no. An illuminated check engine light will cause an automatic emissions test failure.
How long can I drive with the check engine light on?
If it’s solid and the vehicle runs normally, short-term driving is usually okay. If it’s flashing, stop driving and schedule immediate service.