What's Wrong with the 2nd Generation (2004–2009) Prius?

Prius owners have made 812 complaints about the 2004–2009 model years. Using our PainRank™ system we've ranked it 66th out of 81 Toyota generations in overall reliability, with some lights and engine concerns.

Compare With Other Prius Generations

Common 2004-2009 Toyota Prius Problems

Some of the worst issues 2nd generation Prius owners have to deal with.

  2. Unintended Acceleration

    Toyota believes the problems are caused by stuck gas pedals or misplaced floor mats that trapped the gas pedals. Independent testing by NASA and other outside laboratories agreed with Toyota and concluded driver error was also a contributin…

    Continue reading article "Unintended Acceleration"

  3. Prius Headlight Problems

    Prius owners are up in arms about the performance of their high-intensity headlights. Known formally as high-intensity discharge (HID) lights, they either work intermittently -- making nighttime driving a lot more 'exciting' -- or fail enti…

    Continue reading article "Prius Headlight Problems"

What Owners Complain About

Sometimes it helps just to tally up the complaints and see where the biggest stacks are. Use this information to learn about troublespots or to run for the hills.

Worst Issues

What Breaks the Most

Years to Avoid

2nd Generation (2004–2009) Prius Key Numbers

  1. 6 model years

    Grouping all models by their year can reveal some baddies.

  2. 812 complaints

    Running tally of owner grievances filed to CarComplaints.com.

  3. 66th in reliability

    Overall reliability rank out of 81 eligible generations.

Recent 2nd Generation (2004–2009) Prius News

There's a lot of news out there, but not all of it matters. We try to boil down it to the most important bits about things that actually help you with your car problem. Interested in getting these stories in an email? Signup for free email alerts over at CarComplaints.com.

  1. Toyota has blamed a musty A/C smell on microbes [i.e., mold] growing o the evaporator surface and now a lawsuit wants them to do something about it.

    The plaintiffs claim the vehicles have defective heating, ventilation and air conditioning (HVAC) systems that cause smells and health problems from mold that collects on the evaporators. Numerous complaints have allegedly been filed with the government, Toyota and Lexus dealerships nationwide since at least 1999.

    This isn't the first time Toyota has been sued for musty A/C units.

    keep reading article "Air Conditioner Lawsuit Complains About Mold Smell From Toyota HVAC"

  2. Toyota doesn't exactly have a sterling reputation when it comes to unintended acceleration.

    And so, when Corolla owner Robert Ruginis petitioned the National Highway Traffic Safety Administration (NHTSA) to investigate low-speed surging in the 2006-2010 Corolla, it seemed like a slam dunk, home run or <insert sports cliché here>. Go sports team! But instead NHTSA said no to the investigation. The agency said they analyzed data from an event recorder cited by Ruginis in his petition and came up with a completely different conclusion. Ruginis said his Corolla moved forward with the brake pedal pressed, NHTSA said it didn't. Ruginis said Corollas can move forward even with the brake pressed to the floor, NHTSA said they can't.

    Instead, NHTSA placed the blame on Corolla drivers in most cases. They also said an investigation wasn't worth their time:…

    keep reading article "NHTSA Says No to Unintended Acceleration Investigation"

  3. Toyota once said that the Prius is "harmony between man, nature and machine" but that all sounds a bit out of tune to Greg Reynante.

    Mr. Reynante filed a lawsuit alleging Toyota deliberately misled consumers about the fuel efficiency of the 2004-2007 Prius. The lawsuit says the manufacturer ignored factors such as weather, air conditioning and other things that can hurt MPGs. Toyota says it followed the EPA guidelines.…

    keep reading article "Court Battle Over Prius Gas Mileage Claims Continues"

  5. Toyota thought the scourge of unintended acceleration was finally behind them.

    They had, after all, recalled millions of cars, paid hefty fines to the government, entered talks to settle hundreds of class-action lawsuits and even paid out $1.6 billion to owners because the trade-in value of their vehicles had diminished. Besides, the world's attention had turned to GM's ignition switch fiasco. So are Toyota's problems with unintended acceleration in the rearview mirror? Not so fast, or in this case ... slow.…

    keep reading article "New Unintended Acceleration Petition Filed"