The excellent fuel economy is underpinned by a comprehensive package of BlueEFFICIENCY measures as well as by this state-of-the-art engine technology. In addition to the ECO start/stop function that comes as standard, these measures include the new seven-speed 7G-TRONIC PLUS automatic transmission. Low-friction axle drives, electric steering and tyres with low rolling resistance also play their part in reducing fuel consumption.

The re-engineered 7G-TRONIC PLUS, standard on all Mercedes-Benz M-Class models, boasts an integrated ECO start/stop function, even lower converter slip and optimised efficiency. A central role is played by the new torsion damper, which eliminates torsional eccentricities and vibrations in the transmission even more effectively. The lower the rpm and the lower the number of cylinders, the more severe these can be. This results in a conflict of aims between comfort and fuel-efficient operation. Mercedes-Benz developers resolved this by using a so-called twin-turbine damper, which is also fitted with a centrifugal pendulum on the diesel models. Depending on the rpm, this moves the centre of mass and allows comfortable operation even in the most economical operating range. Furthermore, the optimised damping allows a marked reduction in the slip of the torque converter lockup clutch even under low loads, which also contributes to fuel savings. In addition, the optimised damping of rotational irregularities and vibrations in the transmission allows an even faster response to driver commands via the accelerator pedal. Friction-optimised bearings and new transmission oil thermal management also help reduce fuel consumption.

The optimised belt drive system with decoupler, together with intelligent, on-demand control of all ancillary components and pumps, also helps to reduce the energy requirements of the new M-Class. The oil and water pumps in the engine, as well as the fuel pump in the rear section of the vehicle, are only activated according to actual need. The same control logic is used in the THERMATIC and THERMOTRONIC air conditioning systems. In these, the coolant compressor only runs when necessary. An internal heat exchanger and the sophisticated sensor system including a demisting sensor on the front windscreen ensure optimum efficiency of the air conditioning systems in the interior. A key factor in the diesel engines is also the optimisation that has been undertaken of the flow and counterpressure in the exhaust system with its SCR emission control technology.

A consistent use of lightweight construction techniques has enabled the development engineers to keep the weight of the new M-Class on a par with that of its predecessor, despite more equipment. The links on the front and rear axles, for example, along with the bonnet and wings, are made out of light and yet very strong aluminium alloys, while the cross member for the instrument panel is made of magnesium.