Owner's Manual
Page 13
...defect or malfunction of a less serious nature than category (1) has been subject to repair four or more times and you have directly notified Mercedes-Benz USA, LLC in writing of the need for a cumulative total of more substantial defects or malfunctions in the vehicle that are covered... by its express warranty after a reasonable number of the purchase price or lease price, if Mercedes-Benz USA, LLC and/or its authorized repair or service facilities fail to a replacement of your vehicle or a refund of repair ...
...defect or malfunction of a less serious nature than category (1) has been subject to repair four or more times and you have directly notified Mercedes-Benz USA, LLC in writing of the need for a cumulative total of more substantial defects or malfunctions in the vehicle that are covered... by its express warranty after a reasonable number of the purchase price or lease price, if Mercedes-Benz USA, LLC and/or its authorized repair or service facilities fail to a replacement of your vehicle or a refund of repair ...