Servicing & MOT
Repairs
Engine & Drivetrain
Diagnostics & Emissions
More servicesWhat To Do When Your Engine Warning Light Comes On
10 July 2026 · 5 min read
Solid vs flashing — the difference
There are two engine warning lights. A solid light (often called a Check Engine light) means something needs looking at, but it is not an emergency. A flashing light means stop driving immediately — continuing will damage the engine.
If your light is flashing, do not drive to a garage. Call us on 01922 636820 and we will arrange to see you urgently. If it is solid, you can drive carefully to have it diagnosed.
Common causes of the solid warning light
A loose fuel cap is the most common cause — simple and free to fix. Other causes include a faulty oxygen sensor, catalytic converter issues, or problems with emissions controls like the EGR valve or DPF on diesel cars.
The only way to know for sure is to read the fault code using a diagnostic scanner. Most garages can do this quickly and inexpensively.
Why you should not ignore it
Ignoring an engine warning light is tempting, especially if the car seems to run fine. But a small fault can grow into an expensive repair. That faulty oxygen sensor that costs 200 pounds to fix now might lead to a damaged catalytic converter that costs 800 pounds later.
At MF Autocentre in Walsall, we carry out full diagnostic testing. We read the code, test related systems, and give you a clear explanation of what is wrong and what it will cost to fix.
What happens at our garage
We scan your car, identify the fault code, and explain what it means. Many warning lights need only a simple fix — a sensor replacement, a seal, or a fluid top-up. Some need deeper investigation. We quote before any work starts, so no surprises.
Call us on 01922 636820 to book a diagnostic appointment. Most cars can be checked within a day.