The Mercedes, as with most vehicles, is equipped with a "check engine" indicator light. It illuminates when something requires the attention of a mechanic, or to remind you of periodic service needs. The light is designed to come on when the vehicle passes certain mileage limits. You can reset the "check engine" light on your Mercedes within a few minutes.
Insert the key in the ignition switch and turn it without starting the car. Pay attention to the display on the instrument cluster between the speedometer and the tachometer.
Press the lower left button on the left side of the steering wheel. There are four buttons on the left side of the steering wheel. After pushing the button, the display will reveal why the check engine light is lit. Usually it indicates that the car is due for service. Push the lower left button on the steering wheel again and the vehicle mileage will show on the display.
Press the lower right button on the left side of the steering wheel. This will again show the reason why the "check engine" light is on.
Locate the reset button on the left side of the instrument cluster. Press the reset button and hold it until the display reads "To reset: Press reset button for 3 seconds."
Push the reset button again and hold the button in until the display indicates that the system has been reset. The display will also inform you of the next service date according to mileage.
Take your Mercedes in for service when the "check engine" light comes on. Sometimes the light will come on for a minor reason, but there is always a chance of a bigger problem. Have the car serviced before a small issue becomes a big problem. The positive battery cable can be disconnected for 30 seconds to reset the check engine light. This is not recommended because the code for the problem will be erased.