Toyota assigned Yuji Yokoya as chief engineer on the new Sienna project.
Yokoya and his family drove the previous model over 53,000 miles (85,000 km) throughout North America to find weaknesses from the design.
The engine was an updated ULEV certified 3.3-liter 3MZ-FE V6 paired with a new five-speed automatic transmission.
The gear stick was moved from the steering column to the center console and had a gated shift pattern.
Seating for eight was optional on lower-level trims, and the third row seating was fold-flat, allowing the van to transport 4 by 8 feet (1.2 by 2.4 m) building materials like plywood and drywall sheets.

On January 6, 2003, the second-generation Sienna was unveiled at the North American International Auto Show in Detroit.
Production was moved from the Georgetown plant to Toyota Motor Manufacturing Indiana.
Changes from the first generation included 45% more volume overall and 39% more cargo space.
The seats were in the 60/40 split configuration, and the flat-folding third row seat was offered even with all-wheel-drive.

Trim levels, in order of increasing standard and available features were: CE, LE, XLE and XLE Limited (renamed Limited in later years).
The most distinguishable difference on the XLE Limited model was the horizontal chrome bar placed above the rear license plate.
The CE had a black trim there, while the LE and XLE had a body-colored trim.

Standard features included remote keyless entry, tilt-and-telescopic steering wheel, and high solar energy-absorbing glass (HSEA) on the windshield and front windows.
All 2004–2007 Siennas had a factory tow package (hitch kit and trailer lighting connections not included) and a 3,500 pounds (1,600 kg) towing capacity.

All-wheel drive, optional on the more expensive trims included run-flat tires.
The all-wheel drive system continuously divided engine power 50:50 front and rear.

Options, depending on the trim level, included HID Xenon headlamps, Dynamic Laser Cruise Control, parking sensors, a convex rear view mirror to enable the driver to see the passengers, a voice-activated navigation system (not voice activated for the 2004/2005 model year) which included a backup camera, 10-speaker JBL audio and rear-seat DVD entertainment system with two 110 V outlets.

Updated styling allowed for a drag coefficient of Cd=0.30.
EPA Fuel economy was 17 mpg city driving and 23 mpg highway for the FWD version.
The AWD version got 16 mpg city driving and 22 mpg highway driving.
The turning radius was 11.2 metres (37 ft).
Toyota assigned Yuji Yokoya as chief engineer on the new Sienna project. Yokoya and his family drove the previous model over 53,000 miles (85,000 km) throughout North America to find weaknesses from the design. The engine was an updated ULEV certified 3.3-liter 3MZ-FE V6 paired with a new five-speed automatic transmission. The gear stick was moved from the steering column to the center console and had a gated shift pattern. Seating for eight was optional on lower-level trims, and the third row seating was fold-flat, allowing the van to transport 4 by 8 feet (1.2 by 2.4 m) building materials like plywood and drywall sheets.
On January 6, 2003, the second-generation Sienna was unveiled at the North American International Auto Show in Detroit. Production was moved from the Georgetown plant to Toyota Motor Manufacturing Indiana. Changes from the first generation included 45% more volume overall and 39% more cargo space. The seats were in the 60/40 split configuration, and the flat-folding third row seat was offered even with all-wheel-drive.
Trim levels, in order of increasing standard and available features were: CE, LE, XLE and XLE Limited (renamed Limited in later years). The most distinguishable difference on the XLE Limited model was the horizontal chrome bar placed above the rear license plate. The CE had a black trim there, while the LE and XLE had a body-colored trim.
Standard features included remote keyless entry, tilt-and-telescopic steering wheel, and high solar energy-absorbing glass (HSEA) on the windshield and front windows. All 2004–2007 Siennas had a factory tow package (hitch kit and trailer lighting connections not included) and a 3,500 pounds (1,600 kg) towing capacity.
All-wheel drive, optional on the more expensive trims included run-flat tires. The all-wheel drive system continuously divided engine power 50:50 front and rear.
Options, depending on the trim level, included HID Xenon headlamps, Dynamic Laser Cruise Control, parking sensors, a convex rear view mirror to enable the driver to see the passengers, a voice-activated navigation system (not voice activated for the 2004/2005 model year) which included a backup camera, 10-speaker JBL audio and rear-seat DVD entertainment system with two 110 V outlets.
Updated styling allowed for a drag coefficient of Cd=0.30. EPA Fuel economy was 17 mpg city driving and 23 mpg highway for the FWD version. The AWD version got 16 mpg city driving and 22 mpg highway driving. The turning radius was 11.2 metres (37 ft).
Toyota Sienna