Like its non-hybrid RX 350 sibling, the RX 400h luxury SUV gets few changes for 2008. A hybrid-electric drivetrain yields EPA-estimated gas mileage in the mid-20s, a respectable gain over the RX 350's 20-mpg combined rating. Competitors to the RX include the Mercedes-Benz M-Class and Lincoln MKX.
Toyota's luxury division launched the industry's first hybrid luxury SUV at the 2004 North American International Auto Show. Now in its third year, the RX 400h gets a few slight exterior changes and some new colors, but for the most part it's the same as last year's model.
Closely related to the gasoline-powered Lexus RX 350, which falls into the midsize luxury SUV segment, the RX 400h has the Lexus Hybrid Drive system found on the automaker's other hybrids. The electric motor can operate at 12,000 rpm, which is twice the speed of the Prius' motor. Peak output totals 268 horsepower, about the same as the RX 350's conventional V-6.
The RX 400h also has earned a SULEV (Super Ultra Low Emissions Vehicle) rating. The all-wheel-drive system features a separate rear-wheel-drive electric motor. Lexus' Vehicle Dynamics Integrated Management system combines the electronic stability system with new electronic braking technology.
The 400h rides on 17-inch wheels, with 18-inch wheels optional. For 2008, the SUV gets a few more blue hybrid badges, plus chrome door handles and a new grille. Few onlookers will be able to distinguish it from last year's RX 400h, though.
The SUV's overall appearance differs only modestly from the regular RX 350. Styling revisions include round fog lamps and an additional opening on the front bumper for cooling powertrain components. The RX 400h is an inch longer than the RX 350.
The RX 400h's five-passenger seating and interior space are similar to the RX 350's. Rather than the usual tachometer, the dashboard contains an illuminated battery-power meter. The steering wheel contains controls for the hybrid system's monitor and the stereo.
The backseat has been raised 0.7 inches to accommodate the battery pack underneath. Thirty battery modules are split into three groups, each with a dedicated cooling fan.
Standard features include 10-way power front seats and dual-zone automatic climate control. Wood or metallic trim is available, as is a voice-activated navigation system and a rearview camera. The optional rear-seat entertainment system has a 9-inch screen, and a Mark Levinson audio system is available once you add the navigation system.
Under the Hood
Combining a 208-hp, 3.3-liter V-6 and electric motor-generators, the second-generation Lexus Hybrid Drive powertrain generates 268 hp total. A continuously variable transmission sends that energy to the wheels. The full-hybrid system can operate in gas or electric mode, as well as a combination of both. Lexus says the gas engine starts at a lower power level, which makes the transition between power sources harder to discern. Like the RX 350, the RX 400h can tow up to 3,500 pounds when properly equipped.
Antilock brakes incorporate electronic brake-force distribution and brake assist. Side curtain airbags, seat-mounted side-impact airbags and a driver's knee airbag are standard. An Adaptive Front-lighting System, offered as a stand-alone option, can swivel in accord with the front wheels to better light curves in the road. An optional adaptive cruise control feature can slow the vehicle automatically if it gets too close to the vehicle in front of it at highway speeds.
Hybrids might be known for fuel-saving capabilities, but performance reigns supreme in the RX 400h. This SUV zooms confidently and effortlessly from a standstill to highway speed, and it's difficult to discern exactly when the gasoline engine comes into play. Once it does, though, noise from the V-6 is more pronounced than expected from a Lexus, and it quiets down properly at speed.
The ride is pleasant and steering is easy on smooth roads. Bright, recessed gauges are easy to read. You get a full luxury experience, bountiful powertrain response and impressive city fuel-economy figures with this SUV, but the price is hefty.