The maps in the navigation system are colorful and clear, and the route guidance is easy to follow. But this system lacks advanced features, such as traffic reporting or text-to-speech. Similarly, the phone system handles the basics, but won't download your entire phonebook to the car. Instead, you have to manually enter phone numbers to the car's own phonebook. Both the navigation and phone systems handle their basic tasks well, but don't offer the advanced features we've seen in a few other cars.
Audio sources are fewer than on more recent tech-laden cars, with the RX 400h only offering a six-disc CD/DVD player, AM/FM/Satellite radio, and a cassette tape player. Fortunately, that six-disc changer can also read MP3 CDs, but there is no facility for external devices, such as an iPod. Making up for this lack of audio sources is the Mark Levinson audio system. This system uses 11 speakers, including a centerfill, but no subwoofer, and a 210-watt seven-channel amp. The result is very clear sound that lacks punch, making it good for acoustic and symphonic pieces.
Although Lexus hasn't touched the RX 400h's navigation, phone, and entertainment systems in four years, the laser-based adaptive cruise control has been added. As with other adaptive cruise-control systems, you set the car's speed and its following distance, and the car will match speeds with slower traffic in the lane ahead. While other cars are using radar-based systems, Lexus adopted a laser system, similar to the laser guns police use to catch speeders. In our experience with the Lexus system, it worked very well. On more than one occasion it registered a slower car cutting into our lane and hit the brakes quickly enough to avoid a collision and match speeds.
But this system wasn't particularly friendly with the car's hybrid power train. It didn't seem to drive as economically as a human driver would, reacting strongly on the brakes and accelerator in normal traffic where a human might anticipate braking earlier, and get the best advantage out of the car's regenerative brakes.
Under the hood
Similar to other full hybrid cars, the 2008 Lexus RX 400h shuts off its engine at stops and at slow speeds. With light pressure on the accelerator, the car operates as an electric vehicle for short distances, kicking in the gas engine to recharge batteries and supply more drive power when it is called for. In heavy traffic and on city streets with low speed limits, the car makes frugal use of gas. The hybrid system uses the same basic architecture as other Toyota/Lexus hybrids, but in the case of the RX 400h, the gas engine is a 3.3-liter V-6 and there are three electric motors in the drivetrain that, along with the regenerative brakes, can also generate electricity to charge up the battery.
The gas engine produces 208 horsepower on its own, while the front and rear drive motors put out 167 horsepower and 68 horsepower, respectively. But these numbers aren't additive, so total drivetrain horsepower is 268, enough to push the RX 400h to 60mph in 7.3 seconds, according to Lexus. In our subjective experience, the RX 400h shows plenty of get-up-and-go. It doesn't hesitate off the line, delivering smooth and prompt acceleration. Better yet, the transition when the engine kicks in is nearly seamless. In the, you definitely feel when the gas engine kicks in, but in the RX 400h that extra power flows in more smoothly. The car had no problem maintaining freeway speeds over hundreds of miles.
And to reiterate some of our points made above, the electric-power steering is particularly light, which is fine in a parking lot but leads to a squirrelly feeling on the open road. The suspension befits a luxury vehicle, nicely damping out road imperfections. The 17-inch standard wheels can be optioned up to 18 inchers.
We also mentioned the mileage above. Our average while we had the car came out to 25.8 mpg, with many miles of freeway driving thrown in. On our Los Angeles trip, we made it more than 350 miles before we felt it was time to stop for a fill up. The RX 400h is rated as a SULEV, an excellent rating for an SUV, by the California Air Resources Board.
The 2008 Lexus RX 400h lists for $42,580, not a bad price for a luxury SUV. The options on our vehicle included the $600 adaptive cruise control, the $4,130 navigation and Mark Levinson audio package, and the $2,060 Premium package, bringing in features such as high intensity adaptive headlights, leather trim, and the sunroof. Real wood trim added another $380, bringing our total, with a $765 destination charge, to $50,515. The Mercury Mariner Hybrid, with substantially better cabin tech but a less luxurious feel, runs about $15,000 less, making it a better value. For a few thousand more than the RX 400h, you can get the more powerful , which has a decent interior and good cabin tech.
Because of its age, the RX 400h doesn't score well in our ratings for cabin tech. It meets basic requirements in most areas, shines a bit for the audio system, but suffers from the lack of MP3 player compatibility. Its hybrid system gives it a boost for performance tech--we are impressed by the mileage and the emissions rating, and the nice ride doesn't hurt. Similarly, we like the design of both the cabin tech interface, which is intuitive, and the overall look of the car.