How do I reset the maintanace liht on a mercedes benz E350 2009

Reset your Mercedes-Benz key by placing the key in the ignition of your vehicle while the vehicle is turned off. Do not turn on the vehicle. Press a finger on the "lock" button of your key fob while the key is in the Mercedes' ignition.

Pull the key out of the ignition while continuing to hold the "lock" button down. Continue to hold the "lock" button for the duration of the key resetting process

Use another finger to push down on the "unlock" button five consecutive times. Keep holding down the "lock" button.

Release the "lock" button. This is the end of the resetting process for your Mercedes-Benz. Use your key fob to ensure it is properly working