A brand new all-wheel drive diesel sedan is about to be launched on the U.S. market in the form of the 2012 Mercedes-Benz S350 BlueTEC 4MATIC, which will be making its debut next week at the 2011 Detroit Auto Show. It’s been 15 years since a diesel was offered in the S-Class flagship sedan in the U.S. and with fuel prices going the way they are, it couldn’t come sooner.

Under the hood lies Mercedes-Benz’s now familiar 3.0-liter BlueTEC V-6 turbodiesel engine, which already appears in BlueTEC editions of the ML- and GL-Class SUVs. Peak output stands at 210 horsepower and 400 pound-feet of torque.

While these numbers are nothing to get excited about, European models are returning highway mpgs in the high 20s, which is significantly better than the 21 mpg offered by the V-8 powered S550 and even slightly better than the S400 Hybrid. The EPA is yet to reveal its official fuel economy numbers of the new S350 BlueTEC 4MATIC sedan.

Of course, being a 4MATIC means that all-wheel drive will be standard.

Being the least powerful model in the S-Class lineup, the new 2012 Mercedes-Benz S350 BlueTEC 4MATIC should also be the cheapest. However, we won’t know until pricing is revealed closer to the car’s sales launch, pegged for the first quarter of the year.