There are no significant changes to the S40 in 2005. The T5 is now available in a second trim level, which includes all-wheel drive and a sport-tuned suspension. Second generation models were introduced during 2004, sold along side the first generation LSE and 1.9T, but were differentiated by a longer wheelbase, shorter overall length and color-keyed exterior trim.

The 2004 S40 was available in four variants, with the new 2.4i and T5 labeled as 2004.5 models. This year, the 2.4i and T5 return, along with the T5 AWD.

The 2.4i and the T5 both house 2.5 liter inline five cylinder engines. The 2.4i's naturally aspirated power plant provides 168 horsepower and 170 pound-feet of torque. This engine is paired with a five-speed manual transmission, while a five-speed automatic with a manual shift feature is optional. Fuel economy is estimated at 22/29 mpg with the manual and 22/30 mpg with the automatic. The T5's turbocharged mill makes 218 horsepower and 236 pound-feet of torque. The T5 upgrades to a six-speed manual transmission, but the five-speed automatic is still optional. The six-speed offers the strongest S40 fuel economy, at 22/31 mpg.

The new S40 has received positive reviews with respect to build quality, handling, and cabin comfort. Test drivers warn that the sport suspension, found on the AWD T5 and with the Sport Package, has a very intrusive road feel. The S40 is sure-footed, but its limitations are more apparent when driven aggressively. The steering is responsive, but reviewers adds that it could feel more natural.

The interior offers adequate quietness, but the 17-inch tires produce a steady hum on most surfaces. The S40's ergonomics are functional, but some controls are hard to manage on the go. The cabin has a modern look with new higher quality build materials. The second generation models offer a bit more interior room, due to a longer wheelbase.