Hacking your Prius

Do-it-yourself modifications lead to better fuel economy, less annoying beeping and more diagnostic data. Photos: CalCars' souped-up hybrid

Daniel Terdiman Former Senior Writer / News
Daniel Terdiman is a senior writer at CNET News covering Twitter, Net culture, and everything in between.
Daniel Terdiman
5 min read
Heaven knows, Prius owners love their hybrid cars.

But some of the most passionate among them are finding there are certain factory-set features they don't like, and they're increasingly finding ways to take matters into their own hands to change them.

They're the do-it-yourself Prius hackers, many of whom likely are more comfortable in front of a computer than in a garage. But unlike early generations of car buffs, they're more interested in saving the planet than winning a drag race.

"It's the new breed of hot-rodders," said Phillip Torrone, an associate editor at do-it-yourself tech journal Make Magazine. "In the 1950s, it was all about getting more speed. Now, instead of getting more horsepower, it's about getting more miles per gallon. So your hot-rodders are going to be your hot-greeners."

Jacob Gordon, a writer for the online publication Treehugger who has covered several kinds of Prius hacks, said that today's high gas prices and widely publicized energy crisis mandate such behavior.

"People want environmental technological solutions, and they want them faster than the market can necessarily dish them out, so they take things into their own hands," said Gordon. "With hacking the Prius, a lot of it is looking at your energy consumption, and a lot of stuff in the Prius is latently available, because the Prius has such an advanced computer system, but much of it is not available to the driver until you start messing around with it."

It became a pretty tight-knit community. So ideas are passed back and forth.
--Dave Watson
president, Coastal Electronics

Of course, it's not just about the mileage. On late-model Priuses, for example, when the car is in reverse, there is a loud beeping sound. There's also a similar sound when the driver or the front passenger isn't wearing a seat belt. Some people want to turn off the beep.

Though Toyota said there is a method described in the Prius' manual for overriding the backup beeping sound, some say the procedure is not easy to find.

"It's not something they advertise (and) whether it's buried someplace or not, I don't know," said Patricia Pizer, a Los Angeles video game designer and Prius owner. "But they're not very upfront about it."

So what do you do about it? Pizer took advantage of what she said was a relatively simple hack. "It's quite a few steps, and you have to turn the car on and off, and you have to get the sequence right, (but) it was a piece of cake," said Pizer. "It reminded me of beta testers. Beta testers in a game will have a 20-step sequence for finding an exploit, and they're bizarre, bizarre sets of steps. It was very much like that, and I loved the idea of people figuring it out."

Other hacks include making it possible for a Prius to drive mostly on battery power and in the process get nearly 100 miles per gallon, and driving an American Prius in all-electric mode at low speeds--a standard feature on European and Japanese models.

Another hack makes it possible to use the car's onboard navigation system while driving, something that is impossible on a Prius right off a showroom floor.

Dave Watson, president of Coastal Electronics, which markets several Prius modification kits, said that the hybrid car owners generally have the know-how, motivation and connection to other Prius owners to search for the latest hacks.

"The early (Prius) adopters were typically a very high-tech crowd, and there were such long lead-times (to get a Prius) and short supply," Watson said, "that they grouped together, and it became a pretty tight-knit community. So ideas are passed back and forth.

For its part, Toyota recognizes that some Prius owners will want to hack their cars, but the company doesn't condone the behavior.

"There are people out there who have hacked into the system," said Bill Kwong, a Toyota spokesman. "The tech is out there for technicians. But we don't encourage consumers to do that."

Speaking about the hack that allows Prius owners to use the navigation system while driving, Kwong added, "It is hazardous. It's like talking on the phone or shaving while you're operating the vehicle."

But to Watson, whose company sells a system that allows use of the navigation system while driving, that's exactly the point.

"It's an odd situation," Watson said, emphasizing that Coastal Electronics thinks the system should only be used by the passenger in a Prius. "You can use the radio (and other equipment while driving). It's an arbitrary thing as to what is safe and what is not."

Pizer is also a fan of the hack that allows American Prius owners to switch their hybrids to all-electric mode while driving locally at low speeds. She hasn't installed the system yet that enables the on-the-fly switchover, but expects to soon.

And she's perplexed as to why the button that automatically performs the switch on European and Japanese Priuses is missing in the U.S.

"There's a blank spot on my dashboard where the button is supposed to go," Pizer said. "I mean, the whole point of getting this kind of vehicle is supposed to be reducing our use of fossil fuels."

The fact that the feature isn't available in the U.S. may have to do with the way the Environmental Protection Agency measures fuel efficiency in the U.S., and that such a dual-power system would upset such measurements, said Coastal Electronics' Watson.

Kwong said Toyota doesn't offer the switch to electric mode because of U.S. laws mandating that it offer a minimum eight-year warranty for the car's power system. Thus, he said, by disabling the switch, the company is able to ensure a longer battery life.

Torrone said that he thinks Prius owners are likely to keep the hybrid car among the most popular vehicles for hacking for the foreseeable future.

"I think that this might be the new hackable car platform, as there's more (and more) information out there" about the Prius' electronic systems, said Torrone. "Some of this is dangerous, but that's OK. So was modding cars in the 1950s. I think it's all the same, there's just more electricity involved now."