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Review of the Toyota Aqua (Prius C)

Dr. Manura Nanayakkara, a practicing doctor in Sri Lanka, shares the research he did before buying his Toyota Aqua.

Toyota Aqua in a Motor Show

Toyota Aqua in a Motor Show

Toyota Aqua Review

The Toyota Aqua is a full hybrid mini-hatchback car developed for the Japanese market. It is rebranded as "Prius C" in other countries. This review focuses on the Toyota Aqua as there are many reviews of the Prius C on the internet.

Differences Between the Aqua and the Prius C

Since the Prius C is targeted to European and U.S. markets, its safety features are different from the Aqua's. For example, while the basic Aqua has two airbags, even the base grade of Prius C has eight airbags. In addition, the Prius C comes with a special display which shows the energy flow from the battery/engine to wheels; only high-end Japanese Aqua models (G grade) have this display.

In addition, the grades are different for the Aqua and the Prius C. Toyota Aqua comes in L, S and G grades; Prius C comes in 1, 2, and 3 grades. The features of comparable grades are markedly different between the Aqua and the Prius C. Most Japanese Aquas are customized for the original Japanese buyer, except zero-mileage vehicles in Japanese Auctions. So options will vary widely.

Other than that, these two cars are essentially similar. Both have the same engine and hybrid power train. Both have the same external and internal appearance.

The Toyota Aqua is marketed as having a fuel efficiency of 37km/l according to JC008 test cycle. But according to the US Environmental Protection Agency assessment, the Prius C gets 50 miles per gallon (US), equivalent to just 21.7km/l.

Fuel Economy of the Toyota Aqua

It is quite confusing to have two very different fuel economy ratings for essentially the same car. I usually got fuel economy rating in between these two values for my Aqua. I get around 26km/l for average highway and urban driving. Therefore, the EPA rating seems more real-world than the Japanese JC008 test cycle.

The point is that the Aqua has the best fuel economy compared to all other vehicles, after excluding plugin hybrids such as the Prius PHV and Chevrolet Volt.

Toyota Aqua Customer Video

Specifications and Features: Different Versions of the Toyota Aqua

Toyota Aqua is offered in three different grades: L, S, and G. In addition, there are limited edition grades, such as GS and the special Leather Edition.

  • L grade is the base grade. It does not have a rear wiper, power shutters in the rear doors (though it has power shutters in the front doors), a smart key, or a vanity mirror in the front passenger sun visor, and it has smaller tires. However, L grade is 30 kg lighter than other grades (with probably the best fuel economy in the Aqua class). In addition, L grade comes with a spare tire (the other grades come with a puncture repair kit).
  • S grade comes with both front and rear power shutters, push start and rear wiper. Other features vary between cars depending on the customization ordered by the Japanese buyer.
  • G or premium grade vehicles have all the features of S Grade plus features including multi-function Steering, and cruise control.
  • GS and G leather edition come with more exterior customization such as LED fog lights and leather interior.
  • Aqua X Urban, launched in 2014, is currently the highest grade. It has all the features of G grade plus higher ground clearance (160cm vs 140cm).

This list of features and specs can be seen by following link to Toyota's Japanese website. It is in Japanese and you need to have the translator enabled.

Basic Dimensions of the Toyota Aqua

Drive System




Riding Capacity


Weight (kg)


Length (mm)


Width (mm)


Height (mm)




Wheel Base (mm)


Tires Front Tread (mm)


Tires Rear Tread (mm)


Ground Clearance (mm)


Minimum Turning Radius (m)


Looks, Performance and Construction Quality

This is a handsome car. It has good interior and luggage space. It is built aerodynamically to improve fuel efficiency at highway speeds.

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However, I felt that the space in the passenger compartment is restricted. In addition, the build quality looks very cheap. Since you are buying one of the cheapest cars with full hybrid power train, you need to expect low quality cosmetic material.

Performance-wise, Toyota Aqua is similar to other hybrid cars. Initial pickup is not very good. However, if you want to have good pickup, then disable the ECO button. It will cost you more fuel but you will get a performance kick. When you press the gas pedal hard, the hybrid power mode initiates. In hybrid power mode both engine and hybrid battery gives power to the vehicle. It is useful in very tight overtakes. I find it very responsive compared to the Toyota Vitz I had.

Toyota Aqua is built on Toyota’s proprietary Hybrid Synergy Drive© system. It has a 1500cc Atkinson cycle engine with 1Kwh NiMH battery.

Toyota Aqua Drive and Engine Basics

Problems With the Toyota Aqua

Even though Aqua has unbeatable fuel economy, compared to Honda Fit it has the following problems, according to

  1. Less interior space
  2. Less ground clearance, except for X-urban model
  3. Cheap interior materials
  4. Bumpy ride (even compared to the Toyota Vitz, the ride is quite bumpy and uncomfortable)
  5. Less cargo space
  6. Small rear window

First Documented Hybrid Battery Failure in Prius C

A Prius owner reported to Prius chat forums and posted a YouTube video claiming that his Prius C battery failed after four years of use. He drove his vehicle 350,000 km in four years. According to the video he maintained his car poorly. In particular, he did not clean the hybrid battery exhaust fan located on the left side just beneath the rear seat.

How to Drive a Toyota Aqua and Other Hybrids

Unlike a regular vehicle, the engine itself does not start when you switch on the vehicle. Instead, the hybrid system initiates and it will be notified in the display as "READY." When the vehicle is in the READY mode, you can drive it. When the engine starts depends on the condition of the battery and the engine temperature. Until then the vehicle will be driven in EV (Electrical Vehicle) mode.

To achieve maximum fuel efficiency you need to drive the vehicle below 60km/h on normal roads without prolonged hard acceleration or sudden braking. You need to apply the brake gradually.

On highways, you need to keep the vehicle speed below 100km/h and keep the same velocity throughout the journey.

The Toyota Aqua's Hybrid System Indicator

Here the curved meter indicates the amount of power you are applying. If you keep it below "ECO" level then your vehicle runs mostly on EV mode. On the right hand side, PWR range shows where both the battery and the engine give power to the vehicle.

Here the curved meter indicates the amount of power you are applying. If you keep it below "ECO" level then your vehicle runs mostly on EV mode. On the right hand side, PWR range shows where both the battery and the engine give power to the vehicle.

Tips on Driving a Hybrid Vehicle Economically

  1. Drive the vehicle without prolonged hard acceleration (brief acceleration is OK) and without applying the brakes suddenly. Quick acceleration and then gliding will save fuel. This "pulse and glide" method is where you rapidly accelerate to achieve a little above the desired speed and then glide with slight pressure on the accelerator, for example: If you want to drive the vehicle 50km/h, accelerate to 60km/h and use the glide method to slowly decelerate to 45km/h.
  2. To glide, apply enough power to fill one square of the hybrid system indicator. If you want more power, do not use the EV mode excessively, just push a little harder to start the engine.
  3. Sudden braking wastes energy by turning it into heat. During gradual braking, part of the energy is stored in the hybrid battery.
  4. On highways, keep vehicle speed below 100km/h and do not change speed frequently.
  5. Keep short-distance trips to a minimum. Frequent engine warm-ups degrade fuel economy.
  6. Excessive use of EV mode will decrease fuel efficiency and degrade the hybrid battery life.

Service and Maintenance for the Toyota Aqua

According to the Toyota Prius C manual, the engine oil and engine oil filter should be changed every 16,000 km or once yearly, whichever comes first in normal driving conditions. In severe driving conditions (e.g., taxis, police cars with frequent small trips, etc.), engine oil should be changed every 8000 km. This is distinctly different from what the people at service stations tell you. They usually tell that every vehicle should change their engine oil every 5000 km.

The usual engine oil type for this vehicle is 0W- 20, a fully synthetic oil which is somewhat expensive. If you use any other engine oil it should be changed within 8000km.

In addition, you need to change the transaxle (transmission) fluid at 50,000 km. It is very important to change this, as the transmission is one of the most complicated parts in a hybrid vehicle.

Due to regenerative braking, brake pads will usually last around 120,000 kms. This is an advantage of a hybrid vehicle.

Vehicles with hybrid synergy drive do not have fan belts, engine belts, or AC belts. They have an electric radiator pump and a beltless electric brake pump. These functions are performed by electric motors that do not need to be replaced. This is another advantage of a Hybrid vehicle.

However, the Aqua has a lead-acid battery (as do ordinary cars) that needs to be replaced every three years.

The main hybrid battery does not need manual servicing. However, it usually needs to be replaced within 8 to 10 years. When it needs replacing, you will experience a drastic reduction in fuel efficiency and a continuously running internal combustion engine (Minimal EV distance), and there will be an indicator on the dashboard. But as I mentioned earlier, there are reports that some NiMH batteries last more than 12 years.

Toyota Prius C (Aqua) Maintenance Page for 5,000 to 10,000 Miles

It clearly mentions oil change intervals. If you want to see the original then click on the link above.

It clearly mentions oil change intervals. If you want to see the original then click on the link above.

The New Aqua X-Urban

In 2014 Toyota developed a new Aqua model named X-Urban. It has more ground clearance (160mm compared to 140mm) and it is slightly longer than the current Aqua models. It is developed more for off-road travelling. Because it has the same engine and power train configuration, the fuel economy is less than the current model, due to aerodynamic changes and increased vehicle weight. But it would be useful for less-developed or rural roads.

Aqua X - Urban Trim Model

Aqua X - Urban Trim Model

2015 Changes: The Facelift of the Aqua and Prius C

In late 2014, Toyota made some changes to the exterior of Aqua and the Prius C models. However, they have the same engine and hybrid system configuration. They have included LED headlights, and the taillights have been modified for a futuristic look. In addition, now the Aqua is available in combinations of colors. You can check them at Toyota's Japanese website (link is provided above).

Chevrolet Volt - Electric vehicle with gasoline range extender.

Chevrolet Volt - Electric vehicle with gasoline range extender.

Buying a Hybrid: How to Buy an Aqua

If you are not in Japan, then you need to go through a Japanese used car auction to import a Toyota Aqua. But you need to consider that importing a used vehicle from Japan will involve warranty problems unless your country has a genuine Toyota dealership.

Buying a zero-mileage hybrid vehicle could expose you to costly repairs if the vehicle has a manufacturing defect that becomes apparent after some time., e.g., the third generation Prius inverter malfunction. It is safer to buy a vehicle that has a mileage of at least 5000km with more than six months of use.

In addition, you need to consider that it is a right-hand drive vehicle. Therefore, it is mostly imported into Asian countries such as Bangladesh, Pakistan, and Sri Lanka. Some countries such as Sri Lanka offer tax reductions for hybrid vehicles.

You may also want to consider a hybrid buying guide for Japanese auctions.

Prius PHV or Plugin Hybrid Vehicle. Can go up to 26km per charge in EV mode.In addition, it has a gasoline engine.

Prius PHV or Plugin Hybrid Vehicle. Can go up to 26km per charge in EV mode.In addition, it has a gasoline engine.

Fuel Efficient But Mediocre Quality

Toyota Aqua is the Japanese version of Prius C. Compared to the Prius C, it has minor interior and safety differences. It is the most fuel-efficient vehicle in its category, but it has mediocre build quality.

Nissan Leaf - Full Electric Vehicle without gasoline engine.

Nissan Leaf - Full Electric Vehicle without gasoline engine.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

© 2014 Dr Manura Nanayakkara

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