At the heart of the 2006 Toyota Highlander Hybrid, offered as either a front-wheel-drive or 4WD-i (four-wheel drive with intelligence), a 3.3-liter V6 engine that’s nearly identical to the one found in the non-hybrid model includes dual overhead cams, 24 valves, VVT-i (Variable Valve Timing with intelligence), and all-aluminum construction. However, in gas/electric guise, this powerplant is connected to a continuously variable automatic transmission and almost all of the engine components are electrically powered rather than belt driven.

All models supplement the V6’s power with one electric drive motor, while four-wheel-drive models add a 50-kilowatt rear motor that offers up to 96 lb.-ft. of torque. These motors are the same as found in the Toyota Prius, but are twice as fast and twice as powerful for application in the Highlander Hybrid. The gas engine puts out 208 horsepower at 5,600 rpm and 212 lb.-ft. of torque at 4,400 rpm; the front electric motor provides 167 horsepower at 4,500 and 247 lb.-ft. of torque at 0 rpm; the rear motor in four-wheel-drive models offers 68 horsepower at 4,610 rpm and 96 lb.-ft. of torque at 0 rpm. Total net horsepower is 268; an accurate net torque rating cannot be calculated since the gas and electric motors are never working together simultaneously. The EPA rates the 2006 Toyota Highlander Hybrid a Super Ultra Low Emissions Vehicle (SULEV), and suggests that front-wheel-drive units will achieve 33 mpg in the city, 28 mpg on the highway, and 30 mpg combined; four-wheel-drive models are estimated at 31 mpg, 27 mpg, and 29 mpg, respectively.

Like the Prius and the Ford Escape Hybrid, the Toyota Highlander Hybrid is designated a full hybrid, meaning that it is capable of running entirely on electric power under certain conditions. This is due, in part, to a regenerative braking system that captures otherwise wasted energy to recharge a 45-kilowatt/288-volt nickel metal hydride battery located under the second-row seat. Engineers have dubbed it the Electronically Controlled Braking (ECB) system, designed to provide ideal braking through the perfect blend of regenerative braking and hydraulic pressure. ECB ultimately works with 320-mm vented front discs and 287-mm solid rear disc brakes.

The same approach was taken with the Electronic Power Steering (EPS) system, with its focus on quicker and tighter response. This rack-and-pinion setup is connected to a fully independent MacPherson strut suspension with front and rear stabilizer bars, and it all meets the pavement via 17-inch alloy wheels wearing Goodyear Integrity P225/65R17 all-season tires.