The Toyota Prius broke onto the market and quickly changed the game. But for everything the Toyota Prius did for the segment, not everything is perfect in the Prius world. Some Prius models have proven to be more reliable than others while one, in particular, proves to be the worst of them all.

The worst Toyota Prius model year of all

After gathering problems reported by owners about their Toyota Prius models, CarComplaints.com provides a model year comparison of these reports. Looking at the data provides a clear indication that some model years are more reliable than others. The 2010 Toyota Prius receives more complaints than any other model year with 274 reports. The 2008 and 2007 model years aren’t far behind the 2010 Prius, however, receiving 253 and 244 complaints, respectively.

Anyone would assume that the Toyota Prius with the most complaints must be the worst and least-reliable, right? While that assumption may be true for other models, Car Complaints actually rates the 2011 model year as the worst of all Toyota Prius models. With significantly fewer complaints that a few other model years – 104 to be exact – the question must be asked: what is so wrong with the 2011 Toyota Prius?

The 2011 Toyota Prius: problems and high repair costs

According to Car Complaints, the 2011 Toyota Prius is rated the worst model year, and it isn’t because it has received the most complaints. Due to other factors like high repair costs, problems at low mileage, and severity of the reported problem, Car Complaints thinks you should stay away from the 2011 Toyota Prius.

The most commonly reported complaints by owners of the 2011 Prius fall into the engine category, with 35 owners reporting engine problems. Out of 35 owners, 33 of them report excessive oil consumption in their 2011 Prius. This complaint is not only the worst-rated problem with the 2011 Prius, but it’s also the worst-rated problem for all Prius model years as well. Car Complaints gives this problem a Severity Rating of 7.8, estimating that excessive oil consumption is costing owners an average of $4,000 to repair, occuring around 110,000 miles.

32 owners of the 2011 Prius report problems within the lights category, which is also Car Complaints’ worst-rated problem category across all model years. While a few owners complain of headlights needing adjustment or not working properly, 11 owners claim their headlights burn out and 12 more claim that both headlights burn out at the same time. 

Though the brakes problems category has only received 15 complaints, it’s home to the second-worst-ranked problem of the 2011 Toyota Prius. Five owners report their traction control and ABS lights coming on, costing an average of $3,200 to repair, according to Car Complaints. Even worse, nine owners complain that they often have no brakes on bumpy roads, earning a Severity Rating of 8.2 by Car Complaints.

Which Prius model year is the most reliable?

With model years 2006-2011 receiving no less than 100 complaints per model year, assumptions can be made about the design pattern within those years. The 2011 model year, however, seemed to be the wake-up call Toyota needed. The 2012 Prius receives half the number of complaints as the 2011 model year on Car Complaints with 53 total.

The 2013, 2014, and 2015 model years are proving to be some of the most reliable used Toyota Prius vehicles yet, with only 25, 16, and 18, owner-reported problems, respectively. Outside of newer model years, the Toyota Prius models with the least number of complaints may be surprising. Both the 2002 and 2003 Prius model years have less than five complaints, making them some of the oldest, but best-built options.