While it’s true that a blinking engine light can indicate a major problem, the much more usual steady light is most often a sign of a minor malfunction that an experienced mechanic can fix.

But what can cause the warning to light up? Here are seven of the most common problems.

1) Fuel Cap Problem

The most frequently occurring reason for an illuminated engine light is also one of the least serious and most easily fixed. If the vehicle’s fuel cap is damaged or not properly closed, the fuel delivery system can have too much air entering it and probably won’t operate at the optimum pressure. If the light comes on just after filling up, check that the gas cap is properly closed and also that it has no visible damage that could stop it being airtight.

2) Faulty Spark Plugs

If you have a gas-powered vehicle, the spark plugs ultimately keep the engine running smoothly. If they’re old and worn, dirty, or damaged, they’ll create frequent engine misfires which not only lower efficiency but can also cause damage over time. Replacing worn spark plugs is a quick and inexpensive job that’s often done as a matter of routine during servicing.

3) Malfunctioning Catalytic Converter

The catalytic converter is the part of the exhaust system that turns poisonous carbon monoxide fumes into relatively harmless carbon dioxide. If your vehicle’s electronics detect a fault or failure, the engine light will illuminate to warn you that the exhaust may be emitting dangerous fumes while also lowering the engine’s efficiency.

While catalytic converters are relatively easy to replace, they’re rarely the true source of an engine light problem, as their failure is usually caused by other issues such as a blown head gasket. In any case, an inspection should be arranged to isolate the underlying problem.

4) Faulty Oxygen Sensor

Also in the exhaust system, the oxygen sensor measures the amount of unburnt oxygen leaving the engine, and the vehicle’s systems use the information to regulate the mixture of fuel and air entering the cylinders. The oxygen sensor isn’t essential for an engine to work, but without it, fuel economy will be impaired, and there’s also a risk of damage to spark plugs and other vital components.

5) Mass Airflow Sensor Issues

A vehicle’s mass airflow sensor helps to create a fuel-oxygen mix that burns cleanly and efficiently. A malfunctioning unit can potentially damage the engine or other components, so any detected fault will activate the engine light.

6) Sensor Malfunction

Occasionally, the engine light could come on because of a fault in one of the sensors that trigger the warning, and there could be no underlying mechanical issue at all. In these cases, a replacement sensor is enough to solve the issue.

7) Failing Battery

Lastly, without a charged battery, your vehicle will go nowhere. A failing battery will often cause the engine light to come on shortly before the juice runs out completely, and a replacement battery will be a quick and easy fix. This problem is much less common than a few years or decades ago, thanks to improvements in battery technology, but if there’s no other obvious cause for the engine light warning, the battery is the last and most likely culprit.

Whatever the root cause, a check engine light should never be ignored, even if your vehicle seems to be running smoothly in the meantime. To have your engine warning light problems assessed by an experienced mechanic, please book a service appointment by clicking the button below.