The diesel versions were very popular, and the 406 became one of Europe's best-selling diesel-powered cars. Initially, the car was available with 1.8 L and 2.0 L petrol and 1.9 L turbodiesel engines, followed by a 110 bhp 2.1 L turbodiesel, turbocharged 2.0 L and 3.0 L petrol V6 engines. The 2-door coupé was both designed and built by Italian designer Pininfarina, with choices of a 2.0 L 4-cylinder engine or a 3.0 L V6, and from 2001, a 2.2 L HDi diesel engine.
The 406 was notably successful in the UK. It broke into the key UK fleet sales market, with 90 percent of units becoming company cars.
The Facelifted 406 sedan was introduced in 1999 and it has changed in many aspects from the other 406 to make it safer, stronger and faster. The changes include the new and improved EW/DW Engine Family which involves more power and fuel efficiency. Other parts have been changed such as transmission (ratio in fifth increased from 25 to 28 mph/1000rpm), wheels, suspension and brakes. On the exterior, the 406 got a whole new elegant look with more pronounced ribs, totally smooth glass headlights and a new honeycomb grill. The interior has been totally redesigned to create comfort and space as well as a new look. 406 ended production in 2004.