Oil pressure could be the problem - OR - Oil sending unit
if the oil light is on it means the oil pump is not working or faulty.it doesn't mean there is no oil.
The oil change garage or Mercedes dealer has to reset the oil change light. The oil change light goes by the mileage on the car, tripping the light on at the factory recommended oil change intervals. The computer doesn't know you changed the oil in the car unless you tell it. Read your car owners manual.
The red oil light means you car is low on oil, or there is a problem and should be checked.
The car actually measures the viscosity of the oil while you are driving and running the car when you change the oil the light will be reset.
Possibly bad oil pump, too heavy weight of oil, incorrect filter. Sensor for the oil light could malfunction
When the low oil level light comes on, it means that the car has a low level of oil. This means a person needs to add oil to their car.
It means, that you have to refill oil and cooling water.
If it was run without oil, the engine is most likely toast.
oil flow restriction or weak oil pump
The oil light is indicative of extremely low oil pressure. First check the oil level, if the car has little to no oil in it, the light will come on. Assuming the sensor is functioning correctly, and the car has oil in it, the oil light being in would indicate a clogged or broken oil pump which can not provide sufficient oil pressure. Driving with very low oil or a malfunctioning oil pump will damage the internals of the engine in very short order and lead to expensive repairs. If the oil light is on and the oil level is where it should be, you shouldn't drive the car and should have it towed to a mechanic to be looked at.
Defective oil pressure sending unit or the oil pump is defective.
The oil light will always come on for just a second after a car is started. If the oil light stays on, the oil could be low or need to be changed.
If a red oil light comes on in a car, it means the vehicle is low on oil. It could also mean that the oil pump is not working.