| 3rd Gen XW30 (2015) | 1.8L 2ZR-FXE hybrid, NiMH pack (eCVT) | $400-$600 | 3/5 | EGR cooler and intake manifold carbon clogging is the defining third-gen problem - restricted flow raises combustion temperature and is strongly linked to head gasket failure; Oil consumption from worn piston rings at high mileage; check the level monthly on any surviving 2015; Every 2015 is now outside Toyota's 10-year/150,000-mile hybrid battery warranty, so a pack replacement is a live possibility rather than a theoretical one | Very cheap, very durable transport - buy one with service history and do the EGR clean immediately |
| 4th Gen XW50 (2016-2022) | 1.8L 2ZR-FXE hybrid, NiMH or Li-ion (eCVT) | $350-$500 | 5/5 | The EGR carbon behaviour carries over in a much milder form - inspect and clean around 100,000-120,000 miles as cheap insurance, but the third-gen head gasket pattern is far less common; 12V auxiliary battery failure is the leading cause of a Prius that will not power up, and it convincingly imitates far more expensive faults; The HV battery cooling intake behind the rear seat clogs with dust; vacuuming it annually is free and meaningfully extends pack life | The sweet spot - the most reliable Prius generation and the cheapest to run |
| 5th Gen XW60 (2023-2026) | 2.0L M20A-FXS hybrid, lithium-ion (eCVT) | $350-$500 (early data) | 4/5 | Takes 0W-16 rather than 0W-20 - do not let a shop default to the older grade; Lithium-ion pack replaces the NiMH one; still warranted 10 years/150,000 miles; Too new for confirmed long-term cost data, but built on Toyota's most mature hybrid hardware | Newest efficiency and a far quicker car; running costs track the 4th gen closely |