The Toyota ZZ engine family is a straight-4 piston engine series. scion The ZZ series uses an aluminum engine block and aluminum DOHC 4-valvecylinder heads, a first for Toyota. The valve camshafts are chain driven. The two 1.8 L members of the family, the 1ZZ and 2ZZ, use different bore and stroke. The former was optimized for economy and torque, while the latter is a "square" design optimized for high-RPM power. The ZZ family replaced the extremely popular cast-iron 4Aengines Toyota.

• The 1ZZ-FE is a 1.8 L (1794 cc) version built in Toyota Buffalo, West Virginia. Its production in Cambridge, Ontario was engine discontinued in December 2007. Bore is 79 mm and stroke is 91.5 mm. Output is between 120 hp (89 kW) at 5600 rpm with 122 ft•lb (165 N•m) of torque at 4400 rpm, and 140 hp (104 kW) at 6400 rpm with 125.8 ft•lb (170.6 N•m) of torque at 4200 rpm. The cylinders of 1ZZ engines are lined with cast iron. It uses SFI fuel injection, has VVT-i(on later versions) and features fracture-split forged powder metal connecting rods, a one-piece cast camshaft, and either a cast aluminum Toyota intake manifold or a molded plastic one. Excluding the 2003 MR2 and European Celicas with the 1ZZ engine, the 2ZZ engine is also the only model in the ZZ engine family Toyota to engine use a six-speed manual transmission, as well as the only one to have been available with a four-speed Tiptronic-style automatic. These gearboxes were unique to this engine; since then, only a few Toyota engines have been paired with either a six-speed Toyota manual or a Tiptronic-style automatic (and only one other engine, the 4GR-FSE,has received both) Toyota.

Toyota commissioned Yamaha to design Toyota the 2ZZ-GE and it  Toyota shares several similarities with street bike engine Toyota, the most notable being the relatively high RPM design. The high-output cam profile is not activated until approximately 6,200 rpm (the exact point of engagement is different depending on the vehicle, year, and PCM involved) and will not engage until the engine is sufficiently warmed up to 60° celsius (140° fahrenheit). The Toyota PCM electronically limits RPM to about 8200 RPM (or 8400 RPM in some earlier cars) via fuel and/or spark cut. Consequently, it's impossible to "over-rev" the engine with the throttle alone; a downshift from a higher gear must be involved. A typical "over-rev" can damage the oil pump, commonly disintegrating the lobe ring, resulting in damage similar to the picture at right. The oil pump Toyota is the Achilles heel of the 2ZZ, though incidents are rare and usually occur due to fault of the driver. Unfortunately, starving this particular design of oil is almost always fatal to the engine, even when Toyota