Toyota Prius: Car Bible (Second Gen; 2004-2009)
The quintessential hybrid car is more advanced than you might think.
Welcome to the second-generation Toyota Prius Car Bible. As you scroll down you’ll learn all about this vehicle’s quirks, features, finer points, and shortcomings. If you’re thinking about buying one of these, want some help maintaining or modifying one, or just want to deepen your knowledge for the next round of car trivia, you’ve come to the right place.
This is a living document that’s updated as we learn (and confirm) new valuable information. That’s also why the comment section is open. Got something to add? Drop a comment. Got a question we didn’t answer? Go ahead and ask. Our staff will try to reply, and if we can’t, you might get some insight from another reader. Don’t be shy; the more dialogue we have the better this Car Bible will get.
–Andrew P. Collins, Car Bibles Editor-In-Chief
(Disclaimers, Disclosures: Some Car Bibles will have links to specific forums, groups, brands, shops, or vendors for parts shopping and such. We have no sponsorship deals or official affiliation with any of them unless explicitly stated. And as always, we have to add, work on your car and accept advice at your own risk.)
- The Short Story
- How The Hybrid System Works
- Fast Facts
- Spotter’s Guide
- Check This Car Out If …
- Important Trim Levels and Options
- Year-To-Year Changes
- General Reliability and Ownership Costs
- Obscure Details
- Red Flags and Known Issues
- Where To Buy Parts
- Aftermarket Support
- Popular Modifications
- Key Technical Details
- Fluids, Filters, and Capacities
- Factory Service Manuals
- Other References and Resources
- Professional Reviews
- Owner Reviews
- What They’re Worth Now
- Where To Find One for Sale
- What To Ask A Seller
- Competitors To Consider
- Photo Galleries
- Pop-Culture References
- Enthusiast Inquiries
- Downloadable Paperback Car Bible
- Comments Disclaimer
The Short Story
The first Prius was sort of a science experiment by Toyota: Make a car that is half gas, half electric in an effort to create a greener, more fuel-efficient method of transportation. It was received marginally well, but the original car was a bit too small and too slow for many markets outside Japan. For Prius’s second act, Toyota revised the entire car; creating a bigger, better, faster, more efficient version. The second-generation Prius sold like ice-cold water on a summer’s day (exacerbated by the rising fuel costs), as drivers realized they could have a remarkably fuel-efficient car with minimal compromises. This is arguably the most iconic Prius generation.
How The Hybrid System Works
The Prius is a more complicated beast than its pedestrian appearance belies. Beneath that wedgelike, Kammback shape is some pretty sophisticated tech. The tech is so sophisticated that Nissan and Ford used Toyota’s system as a basis for their own early hybrid cars.
There are a few types of hybrids, but we’ll focus on the series and parallels. In a series hybrid, the gas engine is only used to charge the battery, propulsion is solely motivated by the electric motor. In a parallel hybrid, the gas engine and electric motor both can work together to move the car.
The Prius is both and is often referred to as a series-parallel hybrid. The gas motor can be used to solely charge the battery, and thus the electric motor will provide motivation. But, through the use of the power-splitting device (E-CVT), the vehicle’s gas motor can also be used to power the vehicle when the electric motor’s torque or speed is insufficient for the desired performance.
Priuses have a few main parts:
- The gas engine, which provides a great deal of the car’s propulsion, especially at higher speeds
- The electronic (traction) motor called MG2, a high-torque electric motor that gets the vehicle going and assists the gas engine as needed
- Traction battery — the big battery that supplies the traction motor’s electricity
- A generator (often called MG1), which generates electricity, and charges the traction battery
- The power-splitting device, essentially a one-speed transmission that varies the power inputs between electric generation, electric propulsion, and gas propulsion
When starting from a stop, the Prius uses its high-torque electric motor to get going (MG2). From there, the gas motor will join in concert to provide extra assist. MG1, the generator, will also spin (using the gas engine’s power) to charge the traction battery and keep enough energy available for MG2 to use.
This process happens every time you push the accelerator pedal in a Prius. And for those of you who are visual learners, enjoy Toyota’s explanatory video here:
The chassis code (Toyota calls it the “model number”) for this Prius is NHW20.
The second-generation Prius’s gas engine uses the Atkinson Cycle, instead of the Otto Cycle, prioritizing fuel economy and thermal efficiency over outright performance.
This generation’s size hike transformed it from compact car to mid-size car, according to the EPA.
The Prius’s electric drive motor makes 67 horsepower, and its gas motor produces 72 horses. Yet, the net output is only 110 horsepower because of how the Hybrid Synergy drive functions. Both the gas engine and electric motor can’t spin at max power, lest they overspeed and break each other. Also, Toyota insists that higher revs in the gas motor aren’t good for efficiency or economy.
The Prius’s transmission is often called a CVT (continuously variable automatic transmission) or E-CVT, but it’s more of a single-speed differential. There are no belts, cones, or pulleys like you’d find in a Nissan. The car essentially does a complicated dance of varying power inputs from the gas engine, and the high-torque electric motor to effectively create the effect of changing gear ratios. It also controls how fast the battery is charged.
Priuses don’t have actual starter motors. Instead there’s a large electric motor (MG1) that both assists in sustaining the battery’s rate of charge. MG1 also acts as the vehicle’s gas engine starter.
The Prius’s air-conditioning compressor is entirely electric.
The second-generation Prius is probably the most recognizable hybrid car of all time. Cleanly styled, if a bit dowdy, the Prius’s Kammback hatch shape is pretty common on any road, anywhere, in any city, in practically any city or country. All Priuses come with clear prism taillights, a bisected rear glass hatch, a six-window side glass design, and short front overhang.
There have been minimal visual changes over the years, most of which are hard to detect by anyone who’s not a Toyota Prius enthusiast. Even the wheels have remained the same across model grades and model years.
For the first two model years, the Prius was offered in one trim with no options. The 2004 and 2005 model year cars have black upper tailight portions and silver alloy wheels.
For 2006, the car got a mild facelift. The only real changes were located at the rear, where the black upper taillight portions were changed to clear ones. The front got a new grille, complete with a small silver bar.
In 2007, Toyota added a Touring edition, which added a slightly longer rear spoiler and upgraded 16-inch wheels.
All of these parts are interchangeable. It’s possible that a savvy Prius owner could have swapped out pieces from other models. It may not be easy to figure out what year a particular second-generation Prius is just by looking at it on the street.
The Prius has been the best-selling hybrid in the United States. In the U.S. alone, Toyota sold more than 700,000 units of the second generation. It ain’t rare.
Check This Car Out If …
You’re looking for a solidly efficient, reliable, spacious, and inexpensive car that still is on the cusp of technological automotive advancements.
Important Trim Levels and Options
The Prius essentially came in one lone trim for its entire lifespan. In 2006, a Touring model was introduced, but the changes only include a slightly stiffer suspension, 16-inch wheels (compared to 15-inchers on the regular car), a longer rear spoiler, and xenon headlights.
In 2008, a lower-cost “standard” model was introduced. It was mostly the same as other Priuses, yet it didn’t have cruise control, heated mirrors, or front seatback pockets.
Most Priuses have it equipped, but seatback pockets, auxiliary input, and vehicle stability control (VSC) were optional on the Prius.
2004 model year
- Introduced in 2003 as a 2004 model year.
2005 model year
- Rear wiper and washer made standard.
2006 model year
- Revised headlights, taillights, front grille.
- Revised interior infotainment screen; odometer now goes past 299,999.
2007 model year
- Touring model introduced, which adds “touring” suspension, 16-inch wheels, and longer rear spoiler.
- Side and curtain airbags made standard.
2008 model year
- Lower priced “standard” model introduced.
2009 model year
General Reliability and Ownership Costs
The Prius is one of the most reliable vehicles that’s inexpensive to own on the market. The Prius is rated at more than 45 mpg city, and many owners report numbers well past that.
The Prius’s electronic parts are strong and unyielding, and the regenerative braking means that brake pads and rotors often last well past 100,000 miles, depending on driving style. The gas engine’s service intervals tend to be longer than a regular car too.
Higher-mile examples may wear out the traction battery, but that doesn’t seem to happen until well past 180,000 miles. Replacements, rebuilt shops, and rebuild kits are common and fairly inexpensive.
Early 2004 and 2005 Toyota Priuses have digital odometers that only go up to 299,999, regardless of miles or kilometers. Luckily, the gauge cluster still records the excess, so an upgrade can be done that will accurately display the car’s true mileage.
Toyota’s Hybrid Synergy Drive was licensed for use by a lot of manufacturers, including Ford and Nissan. Nissan’s Altima hybrid uses the same battery pack as a Prius and Camry Hybrid; except the gas engine is swapped out for a Nissan QR engine.
When these cars were first introduced, early models had issues with getting stuck in snow because the traction control was hypersensitive.
Despite the Prius’s prevalence as a taxi, delivery vehicle, and other high-mile applications, Toyota never sold a fleet-oriented model of this generation.
Red Flags and Known Issues
The Prius’s long service intervals do not translate to no service intervals. Some lazier owners will neglect the gas engine’s maintenance, leading to general malaise and wear on the gas engine.
The Prius’s 1.5-liter engine is generally a solid unit. The 1NZ-FXE is similar to the 1NZ-FE used in the Toyota Echo. Water pumps and head gaskets can be points of failure.
With age and use, the traction battery’s cells can lose their ability to hold a charge. This will typically be accompanied by increased fuel consumption, a check-engine light, and the “red triangle of doom” signaling an issue with a vehicle’s charging system. Toyota claims to have designed its batteries to last at least 150,000 miles.
Older examples sometimes experience a completely nonfunctional gauge cluster. Luckily, the vehicle will still record mileage, so its replacement can be reprogrammed accurately by a few shops or a Toyota dealer. Be careful while shopping, however. Some owners are unscrupulous and have used that to commit odometer fraud.
Like most Toyotas, the Prius is directly affected by the Takata airbag scandal.
Also in the news, the Prius was one of the models affected by Toyota’s unintended-acceleration scandal, and some models were subject to an ECU reflash and alterations to prevent that from happening.
Certain 2004-2009 models were recalled in 2013 for faulty water pumps.
To get a full rundown of which recalls affect your Prius specifically, pop the VIN (a 17-digit number you’ll find on your title, registration, and stamped in a lower corner of your windshield) into the NHTSA’s search site, or you could try calling a Toyota dealer.
Where To Buy Parts
When the Prius was originally introduced, its place as Toyota’s technological tour de force meant getting parts was mostly a dealer-only affair. Now, its ubiquitous presence on roads and adoption by the nerdiest of car geeks mean there’s a plethora of aftermarket and OEM parts out there for the Prius. Some electronic sensors and parts are still dealer only, but other parts (such as traction battery cells) can be found easily on the aftermarket. Try eBay, RockAuto, Advance Auto Parts, or even Amazon.
Refurbished traction batteries are sold by a number of online and local retailers. Or you can buy the stuff and rebuild it yourself.
The Prius’s sophisticated powertrain is bespoke and unfriendly to any sort of tuning. Its transmission, engine, electric motor, and generator all work within a very complicated set of computer-controlled variables. That part of the car is pretty unmodifiable, either for performance or economy.
Still, the Prius is a popular car with a common wheel-bolt pattern. There are a few options on the market for sportier suspension or better wheels.
If you’re looking for a place to go, HybridPit’s got some options to hot up your Prius.
There’s a whole hypermiling community out there obsessed with getting the most out of their Priuses, but that’s not exactly common.
The Toyota Prius’s catalytic converter is notoriously easy to steal. Owners have come up with solutions, such as welding a cage around it or welding it to the body itself, to stave off potential thieves.
If you’re using your Prius as a fleet vehicle, some have reupholstered their seats in leather or vinyl for ease of cleaning.
Key Technical Details
Engine: 1.5 liters, dual-overhead-cam Atkinson-cycle engine with four valves per cylinder (76 horsepower; 85 pound-feet of torque)
Electric motor: single-magnet electric motor (67 horsepower; 295 pound-feet of torque)
Traction battery: 1.3 KWH, Nickel Metal Hydrate (NiMH)
Transmission: Single-speed direct drive, power-splitting device (E-CVT)
Drivetrain: Front-engine, front-wheel drive
Suspension: In the front, all Priuses use a MacPherson strut design. In the rear, a semi-independent torsion beam holds up the back
Wheelbase: 106.3 in (2700 mm)
Overall length: 175.2 in (4450 mm)
Curb Weight: About 2,850 to 3,000 pounds, depending on equipment packages
Fluids, Filters, and Capacities
Fuel: Toyota recommends 87 octane.
Battery size: S46B24R
Engine oil: 5w-30. Toyota insists on oil changes every 5,000 miles.
Oil filter: The Prius uses Toyota Genuine 90915-YZZF2, a spin-on style filter. There are loads of aftermarket options available, too.
Air filter: Toyota Genuine 17801-21040. Toyota recommends it be inspected at every oil change and replaced if it is dirty.
Cabin air filter: The OEM replacement filter is 87139-47010-83. Toyota recommends changing this filter every 30,000 miles.
Transmission oil: Toyota insists that the transmission fluid is good for the life of the vehicle. If you do insist on changing the transmission fluid, it takes Toyota ATF WS fluid.
Transmission filter: No transmission filter is present on the Prius.
Coolant: Toyota recommends changing the engine coolant every 100,000 miles. The Prius’s power inverter has a separate cooling system that should be changed every 150,000 miles. Both systems use Toyota Super Long Life Coolant. It’s pink.
Power-steering fluid: The Prius uses electric power steering, so, no fluid.
Brake fluid: The OEM rating is DOT3 Spec. Toyota does not have a brake-fluid service interval, but it should be periodically checked for excess moisture. Some owners opt to change every 30,000 or annually.
Spark plugs: Toyota recommends changing the spark plugs every 120,000 miles. The OEM part number is Toyota Genuine 90919-01240.
Factory Service Manuals
Toyota has all of the factory service manuals for the Prius (or any Toyota, for that matter) online for free.
Other References and Resources
The Prius has a lot of engineering references and tech explanations on the internet.
E.A. Hart’s PSD simulator is a great explanation of how the Prius’s transmission works.
For Prius owners of all generations, PriusChat forums are the most comprehensive space to talk about anything Prius-related.
Here’s a cool baseball card-style stat sheet from Toyota’s global website.
“Tested: 2004 Toyota Prius Enters the Mainstream” (Car and Driver, February 2004 print issue)
Frank Markus was less than forgiving about the Prius’s dynamic deficiencies, but he was impressed with the car’s economy.
“Many of us tried to drive the Prius like committed greens. Other less patient colleagues hammered down. Our combined results: 1338 miles per 31.83 gallons, or 42.03 mpg. That’s well up on the 35 mpg we managed from our last Prius.”
“2004 Toyota Prius” (Road & Track, November 2012)
Mike Monticello at Road & Track was enamored with how normal the space-age car felt.
“We’re loving the Prius around town, what with its comfortable ride, plentiful interior room, split/fold-down rear seat and the easy loading ability of its hatchback layout, not to mention infrequent fill-ups. More often than not, people are impressed with how ‘normal’ it is to drive, despite the various propulsion readings being shown on the energy monitor.”
Jessica D. (Sent June 2021)
“My 2007 Prius was the first car that wasn’t a hand-me-down from a sibling, and it’s been a phenomenal car for me. Low maintenance with very few major issues in the years I’ve owned it. I bought it used with 120,000 miles on it already and put another 110,000 on it myself driving all over the Midwest and on the East Coast. Sure, it’s not the fastest or flashiest car on the road, but when what you really need is something to get you places safely, reliably and efficiently, flash doesn’t matter. There’s enough space that I’ve moved furniture, huge IKEA hauls, and trade-show equipment very comfortably. I’ll likely be replacing it within the next year as it’s starting to show its age, but I’ll always have fond memories of it.”
Devin G. (Sent June 2021)
“I took it in on trade at a dealership I worked at. I bought it for $624.75 out the door. It had a rebuilt title and the previous owner claimed he had the hybrid battery replaced with a refurbished one. I drive it for two and a half years, and it never cost me a dime in maintenance besides oil changes. I think it was the second-generation 2005 model. Despite an obvious rebuild, handling was very tight, steering was responsive, and the fuel economy was terrific.”
What They’re Worth Now
The Toyota Prius comes at many price points, depending on condition, mileage, and age. A well-worn, early example with more than 250,000 miles can sell for less than $3,000 in most markets. Newer cars with less than 75,000 miles can sell for close to $10,000.
Where To Find One for Sale
The Prius is very common. It can be found at any type of dealership. Cheaper examples can be bought by private parties via online classifieds.
What To Ask A Seller
Most Prius issues are directly related to the traction battery, so ask if it’s been serviced or replaced. Also ask if the “red triangle of doom” ever popped up on the dashboard. Prius’s charging system faults don’t always trigger any codes, but show up instead as reduced fuel economy. Ask the seller what fuel economy they have been getting.
It may be advantageous to bring an OBD-II scanner and some special software to check the state of health of the traction battery.
Competitors To Consider
The 2010-2014 Honda Insight is newer and cheaper than the Prius, but the Honda IMA system is less efficient and can be problematic on higher-mileage cars.
The 2007-or-newer Camry Hybrid uses a lot of Prius parts and is bigger and more spacious. Still, its fuel economy isn’t as good.
Pricing puts used examples of the Mitsubishi i-MIEV in the same range as a good-condition Prius. Yet, its electric range is very small, and you’ll need to plug it in and charge it.
The 2010-2014 Chevy Volt works well as a series, parallel, or plug-in hybrid, and its EV-only range is impressive for its age. However, the interior is tight and the rear seat only fits two.
If fuel economy and simplicity are what you’re looking for, a used 2014-or-newer Mitsubishi Mirage can be had for the same price as a Prius. It has the best fuel economy of any nonhybrid car sold, but it’s very slow and quite uncomfortable.
Some images can be found buried on Toyota’s global website too.
The Prius has been the butt of many environmentalist jokes over the years.
Karin Dilanette in “Grand Theft Auto” is directly inspired by the Prius. Brian Griffin, the beloved and pretentious dog in “Family Guy,” drives a Prius II. (Peter borrows it to drive for Uber at one point.) “South Park” had an popular episode spoofing what they thought the typical Prius owner was like. Ed Helms’s character on “The Office,” Andy Bernard, tries to kill Dwight (Rainn Wilson) with his Prius in season five, episode 12, of that show.
Surely there are more great Prius cameos in pop culture. Anybody have any favorites to share in the comments?
Every car has a collection of common questions that pop up in forums and Facebook groups whenever new blood joins in. We hope a lot of those have been answered above, but here are some Toyota Prius FAQs we wanted to dig into.
Do I need to plug the Prius in? No. The Prius’s MG1 generator uses the gas engine to charge the vehicle’s traction battery.
Can this car drive as a completely electric vehicle? Yes and no. Some have hacked the Prius and forced it to roll around in an EV-only mode, but it’s limited to 34 mph with a maximum range of two miles. It also may overstress the traction battery.
How long does the battery last? Toyota claims to have engineered the battery to last at least 150,000 or 180,000, depending on the year. Many owners have reported sailing well past 200,000 miles on the original battery. Even still, battery replacements and rebuild kits are common and a lot cheaper now.
Downloadable Paperback Car Bible (Coming Soon)
If you’re old school and like to keep reference notes on paper, or you’re just a completionist and want a free accessory for your Toyota Prius, we’ll have a downloadable doc version soon.
Think of it like an owner’s manual supplement. Keep it in your car and your days of waiting for slow internet on your phone at the auto parts store are over.
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