Why is the engine warning light on in your BMW, Mercedes or Audi?

At Mario Garage in Cagnes-sur-Mer, we see the same situation almost every day: a customer comes in and says — the engine light appeared on the dashboard, what should I do? It’s one of the most common reasons people visit us. And we always say: a warning light never comes on for no reason.

Sometimes the issue is minor, sometimes it's more serious. The sooner you come in for a diagnostic, the cheaper and easier it will be to fix.

What you need to know first

An engine warning light is not a random glitch. It's your car's electronic system warning you that something in the engine isn't functioning properly.

It doesn’t tell you exactly what — it just signals that something is out of range.

That’s why a proper diagnostic is essential.

The most common causes

Based on our experience, especially with German vehicles, here are the top 5 causes:

* Worn spark plugs or ignition coils (very common with BMWs)

* Air leak in the intake system

* Faulty sensor sending incorrect data

* Poor fuel quality or a problem with the lambda sensor

* Incorrect air/fuel mixture

Sometimes the cause is minor — like a loose connector — but if not handled quickly, it can lead to bigger issues.

Why come to us?

We use professional diagnostic tools that are fully compatible with premium brands like BMW, Mercedes, Audi, and Volkswagen.

But more importantly — we don’t just read error codes. We search for the real cause, explain it to you in plain language, and only recommend the repairs you truly need. Nothing more.

Can you keep driving with the engine light on?

Sometimes — yes. But it’s risky. We've seen many cases where drivers ignored the light and ended up with serious repairs: damaged catalytic converter, pistons, or valves. All because they didn’t check in time.

Delaying it can triple your repair costs.

When should you get a diagnostic?

* If the warning light stays on for more than 24 hours

* If your car is losing power

* If the engine makes unusual noises

* If fuel consumption increases

All of these are signs your engine needs attention.

Come visit Mario Garage in Cagnes-sur-Mer — we’ll run a precise diagnostic and clearly explain what’s going on with your car.

Is the check engine light on in your BMW or Mercedes? This warning usually indicates a problem with the engine, exhaust system, or onboard electronics. Ignoring it can lead to more serious and expensive damage.

At Mario Garage, we perform a full diagnostic to identify the issue quickly and accurately.

See how we repair engines at Mario Garage

https://mariogarage.fr/en/diagnostic-moteur

Book your maintenance service now!

Address 105 Chemin du Val de Cagnes 06800 Cagnes-sur-Mer

Phone +33 628 766 484

WhatsApp +33 628 766 484

Opening hours Mon-Fri, 09:00-18:00