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 info. 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 they 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!)

  1. The Short Story
  2. Pictures
  3. How The Hybrid System Works
  4. Fast Facts
  5. Spotter’s Guide
  6. Rarity
  7. Check This Car Out If…
  8. Important Trim Levels and Options
  9. Year-To-Year Changes
  10. General Reliability and Ownership Costs
  11. Obscure Details
  12. Red Flags and Known Issues
  13. Recalls
  14. Where To Buy Parts
  15. Aftermarket Support
  16. Popular Modifications
  17. Key Technical Details
  18. Fluids, Filters, and Capacities
  19. Factory Service Manuals
  20. Other References and Resources
  21. Professional Reviews
  22. Owner Reviews
  23. What They’re Worth Now
  24. Where To Find One For Sale
  25. What To Ask A Seller
  26. Competitors To Consider
  27. Photo Galleries
  28. Pop Culture References
  29. Enthusiast Inquiries
  30. Downloadable Paperback Car Bible
  31. Comments Disclaimer

The Short Story

The first Prius was sort of a science experiment by Toyota; make a car that was half gas, half electric, in an effort to create a greener, more fuel-efficient method of transportation. It was received OK, but the original car was a bit too small and too slow for many markets outside Japan. So for Prius’s second act, Toyota revised the entire car; creating a bigger, better, faster, more efficient version. The second-gen Prius sold like ice-cold water on a summer’s day (exacerbated by the rising fuel costs of the mid-aughts), as drivers realized they could have a remarkably fuel-efficient car with minimal compromises. This is arguably the most iconic Prius generation.

Pictures

How The Hybrid System Works

The Prius is a more complicated beast than its pedestrian appearance belies. Beneath that wedge, kammback shape holds some pretty sophisticated tech. Tech so sophisticated, in fact, 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 most pertinently, 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 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), this high-torque electric motor, gets the vehicle going; it also 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 (often called an E-CVT); 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 put the accelerator pedal down in a Prius. And for those of you who are visual learners, enjoy Toyota’s explainer video here:

Fast Facts

The chassis code (as Toyota calls it “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 midsized car, at least according to the EPA.

The Prius’s electric drive motor makes 67 HP, and its gas motor produces 72 HP. Yet, the net output is only 110 HP, 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 or “E-CVT”, but really it’s more similar to a single-speed differential. There’s no belts, cones, or pulleys like that 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, too.

Priuses don’t have actual starter motors; instead there’s a large electric motor (dubbed 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 A/C compressor is entirely electric.

Spotter’s Guide

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 basically 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 were very 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 been basically the same across model grades and model years. 

Initially, for the first two model years, the Prius was offered in one trim, and no options. 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 being 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.

Still, 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.

Rarity

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. At all.

Check This Car Out If…

You’re looking for a solidly efficient, reliable, spacious, and cheap to run 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. 

Year-To-Year Changes

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:

  • Unchanged.

General Reliability and Ownership Costs

The Prius is one of the most reliable, and cheap to own vehicles 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, are fairly cheap, too.

Obscure Details

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 hyper-sensitive. 

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 (if overheated) head gaskets can be a point 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 non-functional gauge cluster. Luckily, the vehicle will still record mileage, so its replacement can be reprogrammed accurately by a few different shops, or the Toyota dealer itself. Be careful while shopping, though. Some owners are unscrupulous and have used that to straight-up commit odometer fraud.

Recalls

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 any 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 a 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 (like traction battery cells) can be found easily on the aftermarket. Try eBay, RockAuto, Advance Auto Parts, or even Amazon.

Refurbished traction batteries by a number of online and local retailers. Or, you can buy the stuff and rebuild it yourself.

Aftermarket Support

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 um, common.

The Toyota Prius’s catalytic converter is notoriously easy to steal. Owners have come up with solutions, like welding a cage around it, or welding it to the body itself, to stave off potential thieves.

If you’re using your Prius for fleet use, some have reupholstered their seats in leather or vinyl, for ease of cleaning.

Key Technical Details

Engine: 1.5 liters, dual-overhead-cam (DOHC) Atkinson cycle engine, with four valves per cylinder (76 horsepower; 85 ft-lbs of torque)

Electric Motor: single-magnet electric motor (67 horsepower; 295 ft-lbs 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 overly 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 30k, 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

https://techinfo.toyota.com/ has all of the factory service manuals for the Prius (or any Toyota, for that matter), for free.

Other References and Resources

The Prius has a lot of engineering references and tech explanations all over 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.

Reviews

“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 31.832 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 6, 2012)

Mike Monticello at Road & Track was enamored at how normal the space age car felt, back in 2004.

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.

Owner Reviews

Jessica D. (Sent 6/21/2021)

“My 2007 Prius was the first car that wasn’t a hand me down from a sibling and it’s been a phenomenal car to me. Low maintenance with very few major issues in the years I’ve owned it. I bought it used with 120k miles on it already and put another 110k on it myself driving all over the Midwest and 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 it’s age, but I’ll always have fond memories of it.”

Devin G. (Sent 6/21/2021)

“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 second Gen, 2005. Despite being a very obvious rebuild, handling was very tight, steering was responsive, and the fuel economy was terrific!”

What They’re Worth Now

The Toyota Prius’s value can be had 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, lower mile cars can still touch close to $10,000 for example with under 75,000 miles.

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 party, via the usual suspects of online classified websites.

What To Ask A Seller

Most Prius issues are directly related to the traction battery, so ask if it’s been serviced or replaced. Had the “red triangle of doom” ever popped up on the dashboard?

Prius’s charging system faults don’t always trigger any codes, but instead, show up through reduced fuel economy. Ask, the seller, what have they been getting with their fuel economy?

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 mile cars.

The 2007+ 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, it’s 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 is what you’re looking for, a used 2014+ Mitsubishi Mirage can be had for the same price as a Prius. It has the best fuel economy of any non-hybrid car sold, but it’s very slow and quite uncomfortable.

Photo Galleries

Favcars.com and Netcarshow has a lot of pics of the Toyota Prius.

Some images can be found buried on Toyota’s global website, too.

Pop Culture References

The Prius has been the butt of many environmentalist satire jokes in years past.

Grand Theft Auto’s Karin Dilanette is directly inspired by the Prius. Family Guy’s favorite (and pretentious) dog character, Brian Griffin, drives a Prius II (Peter borrows it to drive for Uber at one point). South Park had an infamous (or famous) episode spoofing what they thought the typical Prius owner was like. Ed Helms’ The Office character Andy Bernard tries to kill Dwight (Rainn Wilson) with his Prius in season give, episode 12 (“The Duel”) of that show.

Surely there are more great Prius cameos in pop culture — anybody got more favorites to share in the comments?

Enthusiast Inquiries

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 34MPH, and a max of two miles distance. It also may overstress the traction battery, but some owners disagree.

How long does the battery last? Toyota claims to have engineered the battery to last at least 150,000 miles, 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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Kevin Williams
Kevin Williams

Kevin's been into cars his entire life, anything from the tiny kei cars in Japan, to the maybe not-so-good American barges of the 1980s. He's flipped more than 25 cars, only lost money twice, and has known how to make his dollar stretch as far as it can. If he ain't talking about cars, he's probably snacking on something sweet and cakey. Contact the author here.