Diagnostics

What does it mean when the check engine light comes on?

The check engine light can mean anything from a loose fuel cap to a serious engine problem. Here's how to find out what it actually means, and why you should rarely ignore it.

Check engine light Fault codes Fault-finding

Most drivers have experienced it: a light comes on in the dashboard, and suddenly you're not sure what to think. Is it serious? Can you keep driving? Or should the car go to a workshop right away?

The check engine light is one of the most important warnings your car can give. In this guide we explain what it means, and what you should do.

What is the check engine light?

The check engine light is a warning light that tells you the car's system has detected a fault. Modern cars constantly monitor the engine, exhaust, and electronics via sensors.

When something isn't working as it should, a fault code is stored, and the check engine light comes on.

What can the check engine light mean?

The check engine light can cover many different problems, from minor faults to bigger issues.

Minor problems

  • A loose or faulty fuel cap.
  • A sensor fault.
  • Minor fluctuations in systems.

The car can often keep running, but it should still be checked.

Bigger problems

  • Engine management faults.
  • Problems with the turbo or DPF.
  • Faulty sensors or components.

Here the car can lose power or go into limp mode. If you're also experiencing power loss, you can read more about diagnostics and fault-finding, DPF cleaning, or turbo inspection.

Steady or flashing check engine light – what's the difference?

It's important to know the difference:

  • Steady light: A fault has been registered and should be checked soon.
  • Flashing light: A serious fault, and you should stop the car as soon as possible.

A flashing check engine light can mean a risk of engine damage.

Can you keep driving?

It depends on the situation:

  • Yes, if the car drives normally and the light is steady.
  • Be careful if the car feels different.
  • Stop if the light is flashing or the car loses power.

Rule of thumb: if in doubt, get it checked.

Why you shouldn't ignore the check engine light

Many people choose to ignore the light, but that can get expensive.

If the problem isn't fixed:

  • Minor faults can develop further.
  • Fuel consumption can increase.
  • The engine can suffer damage.

What starts as a small fault can end up as a big repair.

How do you find the fault?

The only way to find the exact cause is through fault-finding.

That involves:

  • Reading out fault codes.
  • Analyzing the car's data.
  • Testing relevant components.

That gives a clear diagnosis and the right solution.

Typical symptoms alongside the check engine light

If the check engine light is on, you might also experience:

  • The car loses power.
  • Uneven acceleration.
  • Increased fuel consumption.
  • The engine goes into limp mode.

These are signs that the problem is affecting the car's performance.

Get your car checked in time

The check engine light isn't something you should ignore. It's the car's way of telling you something needs attention.

At MH Autoteknik Aps we help with professional fault-finding, so you quickly get clarity on the problem and avoid unnecessary repairs.

Next step

Get your car checked before the fault develops

If the check engine light is on, we're happy to help find the cause and give you a clear assessment of the next step.