Why Is the Engine Warning Light Coming On?

Why Is the Engine Warning Light Coming On?


 – Why is the engine oil light so important?

 – Why is the engine warning light coming on?


The activation of the engine warning light is a crucial alert for the engine’s operation. It was one of the first check engine lights to exist in an automobile. Still present today amid a host of warning lights, dials, and other multicolored and luminous information on the dashboard, it should not be overlooked! 

 Why is the engine oil light so important?

 Along with the coolant temperature warning light, it is the only one synonymous with an immediate stop of the vehicle. Its role is to signal a lack or loss of engine oil pressure, which can quickly (within a few minutes) lead to damage or destruction of the engine.

 Please note: its function is related to the oil pressure and not to the oil level in the engine.

 Purpose of the oil circuit in the engine


 An engine is made up of moving metal parts that rub against each other. To prevent wear and tear of the surfaces in contact, a film of oil under pressure ensures the lubrication of the engine parts. This pressure is generated by an oil pump driven by the engine. In addition to the lubrication function, the oil circuit allows:

 – cooling the engine through heat exchange with the hottest parts

 – protection of the metal parts of the engine from corrosion;

 – cleaning the engine of foreign bodies (scale, metal particles, sealant residues, etc.).

 As the oil pressure varies on average from 1 bar at idle to 5 bar at high speed, it is necessary to check the minimum pressure value constantly. If this set value (less than 1 bar) is not reached, a pressure sensor, also known as a “pressure switch” or “oil pressure sensor”, supplies power to the oil pressure warning light on the dashboard.

 How to recognize the oil pressure light?

 The engine warning light is easily identified by its red pictogram representing an oil can. It is often accompanied, on modern vehicles, by a message instructing the engine to stop immediately. It is always possible that the oil sight glass is not working. To check this, each time the vehicle is switched on and before it is started, it is systematically lit up.

 Attention: there is sometimes an engine oil level indicator, often symbolized by a yellow dipstick. It lights up when the engine is cold but is not an emergency for the engine’s operation.

 Why does the engine oil warning light come on?

 If the light comes on, it is essential to turn off the engine as soon as possible. But only after you have cleared your vehicle of traffic! You can then look for the cause.

 Loss of oil pressure

 This is the most likely cause of the oil light coming on. It may be due to a defect in the oil pump, but only a professional diagnosis can confirm this.

 Due to a lack of oil, an abnormally low oil level can cause the pressure to drop and light up the light. In this case, adding oil to the engine should eliminate the malfunction. However, the cause of the oil consumption must be identified by a professional.

 Malfunction of the oil pressure sensor

 The oil pressure sensor may send incorrect information about the pressure value, causing the warning light to come on. You can only detect this by using an oil pressure monitor, and if in doubt, you will have to go to a workshop to have it repaired.

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