The new Jetta TDI is not only important for Volkswagen, it's important for the future of diesel-powered passenger cars in the U.S. It's the first diesel to be available in all 50 states in recent years, and with prices starting at $21,990, it's the least expensive. While diesels have over 50% of that market in some parts of Europe, their presence here is negligible, restricted to cult status.VW, and the diesel industry, are hoping to change that. Diesel engines and the fuel itself are undergoing changes analogous to those that happened to the gasoline engine with the introduction of unleaded gasoline and emissions controls in the 1970s. Ultralow sulfur diesel is the fuel, and sophisticated chemical catalysts and electronic engine and fuel system management are the means to make compression-ignition engines equal to their latest spark-ignition counterparts in their lack of environmental impact. The 2009 Jetta TDI is available now, in sedan and sport wagon form. The cars combine the interior space of the Jetta with the fuel economy of a diesel. EPA ratings are 30 mpg city, 41 highway with the 6-speed manual gearbox, and 29/40 with the automatic, which is the 6-speed DSG twin-clutch automated manual, not a conventional torque-converter automatic. During the press briefing at the recent introduction in Santa Monica, CA, VW representatives claimed that these figures were conservative, with 38/44 obtained by independent testing company AMCI. As always with fuel consumption figures, your mileage may vary. With a base price of $21,990 for the sedan with the stick and $23,090 with the DSG, and wagons at $23,590 and $24,690, the TDI has a price premium of about $2,000 over a comparably equipped gasoline model. That can be partially offset by a $1,300 Federal income tax credit for purchase of an Advanced Lean Burn Technology Motor Vehicle. With the exception of the power train, the TDI is no different from other Jettas, which means a spacious interior and contemporary VW styling. The 2.0 liter TDI engine features a belt-driven single overhead cam and four valves per cylinder, with high-pressure common-rail fuel distribution and piezo direct injectors. Turbocharging increases power and efficiency, and a variety of exhaust treatments, including particulate filtration and diesel oxidation, NOx storage, and hydrogen sulfide slip catalysts clean emissions to Tier 2, bin 5 standards. Even the California Air Resources Board approves. Safety equipment is comprehensive, with six airbags, four-wheel antilock disc brakes, and, like all 2009 Volkswagens, the ESP electronic stability control system all standard. Rear-seat side airbags are optional. Also, as with all '09 VWs, all scheduled maintenance for the first three years or 36,000 miles is free. Cabin information and entertainment systems have been upgraded, and the new navigation system features improved graphics, a touch-screen interface, a built-in 30GB hard drive partitioned 10GB for navigation software and data and 20GB for music, and iPod connectivity.