The Toyota Sienna moved to a four-cylinder engine in the 2021 model year, when Toyota redesigned the minivan to be hybrid-only, using a 2.5-liter inline-four paired with electric motors for about 245 horsepower.
A hybrid-only redesign in 2021
In 2021, Toyota gave the Sienna a complete overhaul that replaced the traditional gasoline V6 with a hybrid powertrain built around a 2.5-liter four-cylinder engine. The new Sienna is offered primarily as a hybrid vehicle, with front-wheel drive standard and all-wheel drive available as an option, reflecting Toyota’s broader electrification push for family vehicles.
From V6 to four-cylinder: a quick history
Prior to the 2021 redesign, the Sienna's lineup relied on gasoline V6 powertrains for most trims, with the 3.5-liter V6 dominating the later generations. The shift to a four-cylinder hybrid in 2021 marked a major departure from that legacy, aligning the model with newer Toyota hybrid systems.
The 2021 powertrain
The 2021 Sienna uses a 2.5-liter inline-four engine with an Atkinson cycle, paired with two electric motors and an electronic CVT. Combined, the system delivers about 245 horsepower. Fuel economy sits in the mid-30s mpg range, depending on whether the vehicle is front-wheel drive or all-wheel drive.
Impact for buyers
For buyers, the shift to a four-cylinder hybrid powertrain means better fuel economy and lower emissions alongside the practicality and space the Sienna offers. While some traditionalists may miss the V6’s power delivery, the hybrid setup emphasizes efficiency, smooth operation, and advanced electrified technology.