What To Do When Your Engine Warning Light Comes On

Red light solid or flashing — which is urgent?

The engine warning light (check engine light) tells you the engine computer has detected a fault. It can mean many things, from a loose fuel cap to a sensor failure to an emissions problem. If the light is solid, the fault is usually not urgent — you can drive carefully to a garage. If it is flashing, that is a serious fault (like a misfiring cylinder damaging the engine); stop driving and call a mechanic right away.

In Smethwick, we can diagnose your warning light the same day. Call ER Automotive on 0121 461 6097 with a description of how the car is running (rough, slow, smoky, etc.) and we will tell you if it is safe to drive in.

How we diagnose engine faults

Our diagnostic scanner reads the fault code stored in your engine computer. This tells us which system is affected — oxygen sensor, catalytic converter, emissions system, spark plugs, or something else. One code might have many causes, so we combine code reading with live data (real-time sensor readings) and physical inspection.

For example, a common code is P0306 (cylinder 6 misfire). This could be a faulty spark plug, a weak coil pack, a fuel injector problem, or low compression in that cylinder. We test each possibility methodically before ordering parts, so you do not pay for guesswork.

What does the fix usually cost?

It depends on the fault. A loose fuel cap costs nothing. A sensor replacement might be £80–£200. A catalytic converter (rare) could be £1,000+. We give you a clear quote for the diagnostic fee (usually credited toward repairs if you book with us) and a separate quote for the fix once we know what is wrong. There is no surprise cost — we call you before we order parts.