2003 TO 2009

Manufacturer	Subaru
Production	2003–2009
Predecessor	Subaru Legacy (third generation)
Successor	Subaru Legacy (fifth generation)
Body style	Four-door sedan Five-door wagon
Layout	All-wheel drive
Engine	2.0 L SOHC 140 hp (100 kW) H4 2.0L DOHC EJ20 H4 2.0L DOHC Turbo EJ20 H4 2.0L DOHC TD EE20 H4 2.5L SOHC EJ253 H4 2.5L DOHC Turbo EJ255 H4 3.0L EZ30 DOHC H6
Transmission	4-speed automatic 5-speed automatic 5-speed manual 6-speed manual
Wheelbase	105.1 in (2,670 mm)
Length	4,729 mm (186.2 in) (sedan) 4,793 mm (188.7 in) (wagon) 4,796 mm (188.8 in) (2008–2009)
Width	1,730 mm (68.1 in)
Height	1,480 mm (58.1 in) (wagon) 1,420 mm (56.1 in) (sedan) 1,440 mm (56.5 in) (Spec B Sedan)
Curb weight	1,600 kg (3,500 lb) max
Related	Subaru Outback Subaru Tribeca Subaru Exiga

The fourth generation of the Subaru Legacy was introduced in 2003 and saw a complete redesign of the Legacy on an all-new platform.

Japanese model

On May 23, 2003, Fuji Heavy Industries debuted the fourth generation Legacy B4 Sedan and Touring Wagon for the Japanese Domestic Market. The Legacy was presented the 2003–2004 Japan Car of the Year, Subaru's first win for the award. In Japan, the Legacy was no longer regarded as a "small car" under Japanese vehicle size legislation due to its length over 4.7 meters, and width dimensions over 1.7 meters.

Starting with this generation, Subaru installed an electroluminescent instrument cluster which lights up when the engine is started, regardless if the exterior lights are on.

For the home market, the Legacy B4 and Touring Wagon were offered in 2.0i, 2.0R, 2.0GT, 2.0GT spec.B, 3.0R, and 3.0R spec.B trim levels. The base model 2.0i has SOHC version of EJ20 engine producing 140 PS, and the 2.0R comes with 190 PS DOHC engine. The turbocharged EJ20 DOHC engine installed in the 2.0GT and 2.0GT spec.B producing 280 PS. The 3.0R and 3.0R spec.B are powered by the new 250 PS 6-cylinder EZ30 engine.

To commemorate Subaru's 50 years of making automobiles, the 50th Anniversary Legacy was released in January 2004. This special edition model was based on the Legacy 2.0R, and 2.0GT.

The Legacy Blitzen of December 2004 is the special edition based on the 2.0GT B4 and Touring Wagon. These high-performance sports models came with special colour bright red, sports suspension, 18-inch alloys, unique grille, and aero-style bumpers.

Based on the Legacy 2.0GT spec.B B4 and Touring Wagon, the WR-Limited 2004 was released in July 2004, and the 2.0GT-based WR-Limited 2005 was launched in August 2005. The WR-Limited models were painted in WR Blue Mica, and came with Gold alloy wheels, front under spoiler, special blue and black seats, and special emblems.

Also added to the Japanese line-up in August 2005 was the Legacy 2.0GT spec.B tuned by STI. This sports model has Bilstein suspension, 6-speed manual, STI genome exhaust, Brembo brakes (4-piston front, 2-piston rear) and 18-inch alloy wheels by STI.

Facelift model

The Japanese Legacy received a cosmetic update in May 2006; Notable changes included new bumpers, headlights, front fenders, grille, and rear combination lamps. This facelift trickled down to export models in 2007, and the American market's 2008 model year.

Although model grades remained largely unchanged, the number of option packages available for certain grades reduced. The base model 2.0i Touring Wagon could also be ordered as the Casual Selection model. Urban Selection models were added to the 2.0R, 2.0GT, and 2.0GT SI-Cruise. The 2.0R was also offered as B-Sports Limited version.

EyeSight (2008–09)

On 2008-05-08, Subaru announced the EyeSight models for Japanese market. It consists of 2 cameras with one on each side of the rear-view mirror, that use human like stereoscopic vision to judge distances and generally keep tabs on the driver. The system can help you keep your distance on the highway, a lane departure warning system, a wake up call should everyone pull away from the lights but you, and even keeps an eye out for pedestrians. SI-Cruise has been integrated into the EyeSight feature as a driver safety aid.

EyeSight models were available for Touring Wagon 2.0GT and 3.0R, B4 3.0R, Outback 3.0R. All EyeSight models include Sportshift E-5AT transmission.

STI S402 (DBA-BL9/DBA-BP9) (2008–2009)

The Legacy STI S402 is a limited edition (402 units) high-performance series for the Japanese market. It includes a 2.5L twin scroll turbo engine rated 285 PS (210 kW; 281 hp) at 5600 rpm and 392 N·m (289 lb·ft) at 2000–4800 rpm, Bilstein shocks, 18x8-inch BBS forged wheels (from S203, S204) with Potenza RE050A 235/40R18 91W tires, Brembo 6-piston front and 2-piston rear brake calipers (from Subaru Impreza type RA-R), Vehicle Dynamic Control stability control. A special serial number plate is added to the center console and engine bay VIN plate.

Variable valve timing was added. ECU was updated to improve acceleration.

S402 was available in sedan and wagon bodies.

Basic equipment

The basic equipment list includes equipment that is standard across all versions of the Subaru Legacy Sports Tourer (03-09).

American model

Subaru of America commencing production of the Legacy BL and BP in January 2004 for the United States and Canadian markets. Lance Armstrong was used as a spokesman for both the sedan and wagon, and Sheryl Crow sang her 1996 hit "Everyday Is a Winding Road" in USA market commercials.

It marked the return of a turbocharged engine to North American Legacy, featuring a 2.5-liter unit derived from that of the North American Impreza WRX STI. Due to advancements in turbocharger technology and tightening emission standards, the twin-turbo setup was dropped from the lineup. Turbocharged models and the H6 offered Subaru's first 5-speed automatic transmission, featuring SportShift technology licensed from Prodrive, Ltd.

The 2005 model year Legacy for the US market was offered in 2.5i, 2.5i Limited, 2.5GT, and 2.5GT Limited. All trim levels were available as Sedan and Wagon. For 2006, the regular GT was dropped, and the 2.5i Special Edition was added into the line up. Manual transmission is also discontinued in station wagon body. Priced between the base and the Limited models, the 2.5i Special Edition came with power moonroof and power driver seat, while the 2.5i Limited also came with leather interior, power front passenger seat, and climate control automatic air condition.

The high-performance Subaru Legacy 2.5GT spec.B arrived as 500 units limited edition model for 2006 model year in America, and became a regular model for the next following years. It has Bilstein shock absorbers and 18-inch alloy wheels for better handling, Vehicle Dynamics Control, and from 2007, 6-speed manual gearbox and the Subaru Intelligent Drive (SI-Drive) with three modes: Intelligent, Sport, and Sport Sharp. The 2.5GT spec.B model is only available in the sedan body and not the station wagon body.

For the 2008 model year, the Legacy sedan received facelift with new bumpers, front fenders, tail lights, and alloy wheels. By this time the Legacy wagon and Outback sedan were discontinued in the United States, leaving the Legacy sedan and Outback wagon. The Legacy wagon was not discontinued in Canada. 2008 also brought the 3.0 L flat-6 engine to the North American Legacy sedan in the 3.0R Limited trim level. The flat-6 has been available in the Outback sedan wagon since 2000. For 2008, the 2.5i USA model has been certified PZEV emissions, and a badge has been attached to the rear of the vehicle on the bottom right hand side of the trunklid or tailgate. All other models are certified LEV2. The PZEV Legacy is available for sale in all 50 states, unlike other manufacturers who only sell PZEV certified vehicles in states that have adopted California emission standards.

European Model

Ecomatic Autogas Hybrid (2007–)

The Ecomatic Autogas Hybrid is a version of the Legacy with the 2.0R or 2.5i engine that can run on LPG for German market.

Diesel (2008–)

The Subaru EE flat-4 diesel engine is offered in both the Legacy and Outback sedans and wagons, identified as the Subaru Legacy 2.0D; the vehicle was released in the EU starting March 2008. The vehicle is offered with a 5-speed manual transmission only.

The official introduction of the Legacy and Outback diesel was at the Geneva AutoShow in March, 2008.

According to the Subaru Insiders on-line newsletter dated March 2008, Subaru is "currently making modifications to the diesel so it meets the more stringent U.S. standards. Subaru diesel models should be domestically available in two to three years."

Australian Model

The Liberty BL and BP were offered in Australia from 2004. Initially the model grades were 2.0i, 2.5i, 2.0GT, 3.0R, and 3.0R spec.B. The 2.5i could also be ordered with Luxury Pack (in-dash CD Player, leather interior, power driver's seat, sunroof), Safety Pack (dual front side and curtain airbags), or Premium Pack which is the combination of Luxury and Safety Packs. Premium Pack was also offered for the GT. In 2006 the Liberty 2.0i became 2.0R, and the 3.0R spec.B was also available as Blitzen model with sport grill and aero bumpers. For 2007 model year the Liberty GT and new GT spec.B received bigger 2.5-liter turbocharged engine. 

Liberty GT tuned by STi (2006 & 2008)

In 2006, Subaru released the 300 units limited edition Liberty GT tuned by STi based on the 2.0GT Sedan and Wagon. The facelift versions of 250 units were released for 2008 model year and powered by the 2.5-liter turbo engine. The modified EJ255 engine is rated 264 PS (194 kW; 260 hp) at 6000 rpm and 350 N·m (260 lb·ft) at 2800 rpm. It includes Bilstein shocks, rear suspension kit with partial ball bearing-jointed bushes, 5 mm (0.2 in) lower springs, Brembo brakes (4-piston front, 2-piston rear) with stainless steel mesh-type brake hose, 18-inch ENKEI wheels (2.5 kg (5.5 lb) lighter over stock), front and rear STI spoilers, leather and alcantara front seats, 8-way power driver seat with memory settings.