If a warning light has appeared on your dashboard, it can be worrying — especially when you don’t know what it means or whether it’s safe to keep driving. At Birway, we carry out diagnostic checks every day, and one of the most common questions we hear is: “What does this warning light actually mean?”

The truth is, fault codes can look complicated — but they don’t have to be. In this guide, we’ll break down some of the most common ones in plain English, so you know what to look out for and when to get your vehicle checked.

What is a fault code?

Your vehicle is constantly monitoring itself through an onboard computer system. When something isn’t working as it should, it logs a fault code and often triggers a warning light on your dashboard. These codes give us a starting point, but they don’t always tell the full story.

That’s why proper diagnostics are important — it’s not just about reading the code, it’s about finding the real cause behind it. At Birway, we don’t just plug in a machine and guess — we diagnose the issue properly so you’re not paying for unnecessary parts.

Check engine light (engine management light)

This is one of the most common warning lights drivers see, and it can come on for a wide range of reasons. In simple terms, it means something in the engine or emissions system isn’t working as it should. That could be anything from a faulty sensor to an issue with fuel or ignition.

If the light is steady, the issue may not be urgent — but it still needs checking. If it starts flashing, that’s a sign of a more serious problem and you should stop driving as soon as it’s safe to do so. We can run a full diagnostic check at Birway Garage to pinpoint the exact cause and get it sorted.

ABS warning light

The ABS system helps prevent your wheels from locking under heavy braking, giving you more control in emergency situations. If this light comes on, your standard brakes will still work, but the ABS function may not.

This is often caused by a sensor issue or a fault within the system. It’s not something to ignore, especially in wet or slippery conditions, so we recommend getting it checked as soon as possible.

Tyre pressure monitoring system (TPMS) light

This warning light usually indicates that one or more of your tyres is not at the correct pressure. In many cases, it’s something simple like low tyre pressure — but it can also point to a slow puncture or a sensor fault.

Driving with incorrect tyre pressure affects handling, braking and tyre wear, so it’s always worth checking straight away. We can check your tyres, repair punctures where possible and reset the system if needed.

Battery warning light

A battery warning light doesn’t always mean you need a new battery. More often, it’s linked to the vehicle’s charging system. This could be caused by a failing alternator, a weak battery, or an issue with the electrical system.

If the light stays on while driving, your car may not be charging properly. If left too long, the vehicle could eventually lose power completely — so it’s best to get it checked early.

DPF warning light (diesel vehicles)

If you drive a diesel vehicle, you may see a DPF warning light. This relates to the diesel particulate filter, which helps reduce emissions. This light often comes on when the filter becomes blocked, usually due to short journeys or stop-start driving where the system doesn’t get a chance to clean itself properly. In some cases, the issue can be resolved with a regeneration process — but if ignored, it can lead to more serious and costly repairs.

Airbag warning light

The airbag light is one you should never ignore. If it’s on, it means there’s a fault somewhere in the airbag system. This could be something as simple as a sensor or wiring issue — but it also means your airbags may not deploy correctly in an accident. For safety reasons, we always recommend getting this checked as soon as possible.

Why fault codes don’t always tell the full story

One of the biggest misconceptions is that a fault code tells you exactly what part needs replacing. In reality, it’s more of a clue than a final answer. For example, a sensor fault might actually be caused by wiring, a connection issue, or another related component.

Simply replacing parts without proper diagnosis can end up costing more in the long run. That’s why we take the time to diagnose the root cause properly at Birway Garage.

When should you get a fault checked?

If a warning light stays on, starts flashing, or your vehicle doesn’t feel quite right, it’s always best to get it checked sooner rather than later. Ignoring warning lights can lead to bigger issues, reduced performance and more expensive repairs. In short — if something doesn’t seem right, it’s worth getting peace of mind.

Book a diagnostic check at Birway Garage

If you’ve got a warning light on your dashboard or you’re unsure what a fault code means, we’re here to help. At Birway, we offer professional diagnostic checks to identify issues quickly and accurately, with honest advice on what’s needed next.

Contact us today to book your diagnostic check and get your vehicle back to its best.