New features in the 2012 M-Class include an updated 7G-Tronic Plus seven-speed automatic transmission to provide improved fuel economy, optional Adaptive Cruise Control (Distronic Plus), Active Lane Departure Warning System, and an adjustable-height air suspension (AirMatic). An ACTIVE CURVE SYSTEM with active anti-roll bars for body roll compensation was introduced.
The W166 was one of the last vestiges of the joint venture between Daimler and Chrysler while they were a consolidated company. Daimler-Chrysler developed the core platform and technology, benefitting from Chrysler's strong SUV sales and R&D domestically. The underlying platform work was largely completed in 2006, as the two companies were separated. Chrysler uses the same platform to power the Jeep Grand Cherokee (WK2) and Dodge Durango. Because of the separation however, the cars are extremely different in terms of interior and body design as well as engine choices. Aside from engines, the three SUVs share many powertrain components, including some transmissions.
An On&Off Road Package is available for most markets (now including North America) as of the 2013 model year. The package adds a two-speed dual range Magna Powertrain transfer case with center differential lock, reduction gearing, underbody skid plates, and a 6-mode selectable terrain driving program system. The rear differential lock has been discontinued.
Open front and rear differentials are fitted, and use four-wheel electronic traction system (4-ETS) to simulate front and rear differential locks.
The Mercedes M-Class won first place in the "Luxury Crossover SUV" category and has been named the most ideal vehicle for Americans based on a study undertaken by California-based automotive research and consulting firm AutoPacific.