# Check engine light (engine warning light): what it means and what to do _Updated: 9 November 2026_ **Short answer:** Check engine is the engine-shaped light, and it comes on when the engine computer finds a fault. If it stays on, you can drive, but get it checked as soon as possible; if it flashes, the engine is misfiring and can damage the catalytic converter, so drive slowly and get it checked straight away. > **The service we recommend: Diagnostics** We read faults from every computer in the car and tell you what is urgent. We tell you the price when you tell us the model. [More about the service](https://autoindustrija.rs/en/services/car-diagnostics) ## Can you drive with the engine light on - **The light stays on and the car runs as before:** You can drive, but no long drives. Take the car for a check as soon as possible. - **The light is on and the car pulls weaker or jerks:** The fault is already affecting how the engine runs. The light also comes on when the computer switches the engine to a backup mode. Take the car for a check as soon as possible. - **The light flashes:** The engine is misfiring. Go for a check straight away. Until then drive slowly, without hard acceleration or hard braking. Avoid steep hills and carry as little load as you can. If after a while the light stops flashing and stays on, it still needs a check. - **The engine light is red:** Red means a serious fault. Stop as soon as it is safe and do not drive on. - **The red oil or temperature light is on as well:** Stop as soon as it is safe. A red light means you act straight away. [More about the oil light](https://autoindustrija.rs/en/advice/oil-warning-light) - **The light comes on when you turn the key and goes out once the engine starts:** That is not a fault. This is how the car checks that the light works. ## What the engine light means The engine computer constantly watches the engine and the parts that clean the exhaust, and when it finds a fault it turns on the light and stores the fault. The light does not say what the fault is. The same sign comes on for a badly closed fuel cap and for a fault that damages the catalytic converter. That is why nobody knows how serious the fault is until we read it. [More about dashboard lights](https://autoindustrija.rs/en/advice/dashboard-warning-lights) ## The most common causes - A badly closed or wrong fuel cap. - Spark plugs or ignition coils, which ignite the fuel in a petrol engine. The engine then misfires and shakes, and the light may flash. - A faulty sensor, for example the mass airflow sensor or the lambda sensor. - The EGR valve, which sends part of the exhaust gases back into the engine, or the injectors. - The catalytic converter, or on a diesel the DPF filter, which traps soot, or the AdBlue system. Many different faults turn on the light, so the symptom does not tell you which part is to blame. ## What happens if you drive with the light on The fault behind the light often raises fuel consumption, lowers engine power or makes the car jerk. The longer you drive with the fault, the bigger the chance it damages other parts too. When the light flashes, the catalytic converter, the part that cleans the exhaust gases, is at risk, and replacing it is expensive. So go for a check straight away. [More about car diagnostics](https://autoindustrija.rs/en/services/car-diagnostics) ## The engine light comes on and goes off A light that comes on and goes off means the computer sees the fault only sometimes, under certain driving conditions. The light goes out by itself when the computer does not see the same fault for several drives in a row. If it comes back after that, the fault has not been fixed. ## How the fault is found Along with the fault, the computer stores the state of the engine when it happened: revs, temperature and speed, so you can see when the fault appears. After the repair the light usually goes out by itself. Clearing the fault without a repair only turns it off for a while, because the fault stays. ## The engine light and the technical inspection At the technical inspection, the system that warns of a fault in the emissions equipment is checked through the OBD port. The Serbian rulebook on technical inspection requires this. The engine light is exactly that warning. **Whether the light is checked at the inspection depends on fuel and year** - **Petrol:** from 2001. - **Diesel:** from 2004. When the light is on, do not wait for the inspection. Have diagnostics done a few days before the inspection, so you know in time what needs fixing. Do not clear the fault the day before the inspection. After clearing, the computer has to finish its checks again, which takes about a week of normal driving. The same goes after the battery is replaced or disconnected. [More about the technical inspection and OBD](https://autoindustrija.rs/en/advice/relocated-obd-port-inspection) ## Frequently asked questions ### The engine light came on after filling up. What should I do? Unscrew the fuel cap and screw it back on, clockwise, until you hear a click. The light does not go out straight away, only after a few drives. If it is still on after that, or if it flashes, the cause is something else, so the fault needs to be read at diagnostics. ### The glow plug light is on together with the engine light. What does it mean? On some diesels, for example Volkswagens, the glow plug light is also the engine light. When it stays on or flashes while the engine is running, the fault can be in the glow plugs or in another part of the engine. The car may then have less power. Drive gently and get it checked as soon as you can. [More about the glow plug light](https://autoindustrija.rs/en/advice/diesel-glow-plug-light) Have a question about your car? Message us on WhatsApp or call 067 774 1606. ## Read also - [Car dashboard warning lights: meaning and when to stop](https://autoindustrija.rs/en/advice/dashboard-warning-lights) - [Car won't start: what to check first](https://autoindustrija.rs/en/advice/car-wont-start) - [Battery warning light on: alternator or battery?](https://autoindustrija.rs/en/advice/battery-warning-light) --- Page on the website: https://autoindustrija.rs/en/advice/check-engine-light auto-industrija, Belgrade. Phone and WhatsApp: +381677741606. E-mail: kontakt@autoindustrija.rs.