Prius Shifter B Mode: Everything You Need To Know

Your Toyota Prius comes with many features that not only make it greener and more energy-efficient but also easy to drive.

The Prius shifter knob provides the driver with different ways to maneuver the car in the right way. One mode on the shifter – “B” – is one that we are asked about often.

Here, we’ll answer the following questions:

• What does the B stand for in a Prius?
• How does the Prius shifter B mode work?
• When should you use Prius B mode?
• When should you avoid using B mode when driving a Prius?
• Can you shift from D to B while driving?
• How do you use the B gear?
• What is the most efficient way to drive a Prius?
  

What Does the B Stand For In A Prius?

Simply put, the Prius B mode stands for “braking.” This position is for shifting into a lower gear and increases the engine’s drag to help slow your vehicle down. But when would you need this mode?

How Does the Prius Shifter B Mode Work?

Much like with a conventional car, downshifting into the B mode on a Prius causes the engine to spin faster than it needs to. When this happens, the energy required for it to do so causes the car to slow down.

The energy is expended through vacuum losses and is essentially “wasted” energy but works to help extend your brakes’ life and prevent overexertion. 

When Should You Use Prius Shifter B Mode?

If you’re on a long, steep graded downhill slope, you’ll want to use the engine feature to help your regenerative braking from being overloaded. For example, when descending a road that goes over a mountain or steep hill. Consistently using the brakes in this circumstance to stabilize your speed can not only wear the brakes out, but it will get them very hot.

B mode may also help in icy conditions, as braking on slippery pavement can cause your vehicle to slide. Downshifting into B mode can help slow your car down without stopping abruptly and potentially slipping out of control.

When Should You Avoid Using Prius Shifter B Mode When Driving?

It’s best to avoid using B mode on your shifter during regular driving. There is no advantage to using the mode when it isn’t required, as it throws energy away unnecessarily, and doesn’t recharge the hybrid battery.

Since regenerative braking works when the regular brakes are used, you’d be doing yourself no favors by using B mode to brake when it’s not needed.

The only exception to this recommendation is with the plug-in Prius that has an option for electric vehicle (EV) drive mode. In this mode, the vehicle is only getting power from the hybrid battery and not from gasoline. 

Can You Shift From D To B While Driving?

Yes – that’s the only time you can shift to B. You cannot go directly from park (P) to B – though you can go from B to P). 

The Prius has complex electronic components, and you shouldn’t worry about whether you can shift a certain way. If going from one particular gear to another will damage the vehicle or be unsafe to the driver, the Prius will not allow you to make the change. 

For example, shifting from Drive to Reverse while in motion will put you into neutral. The Prius won’t allow the change, as it could damage the transmission and be unsafe for the driver.

How Do You Use the Prius Shifter B Mode?

If you are on a steep downgrade and want to protect your vehicle’s brake pads and regenerative braking system, switching to B mode is simple. 

The most important thing is to first slow to an appropriate speed using your normal, regenerative brakes. This speed should be one you’re comfortable cruising down the hill at and is within the speed limit. 

Once you’re at a lower speed, change the shifter knob to B. You won’t need your foot on the brake to do this.

The engine will sound as if it is “revving” loudly, but this is the engine spinning faster to help to maintain a safe speed without utilizing the brakes.

You will then be kept at that speed and cruise down the steep hill until you inevitably reach the bottom and change the shifter back to D.

What Is The Most Efficient Way to Drive a Prius?

Using Prius shifter B mode is one way to help keep your vehicle in good health, especially the brakes. You can do a few other things to make sure you’re always efficiently driving your hybrid – especially if you’d like to get the best gas mileage and keep your hybrid battery healthy.

1. Choose the best route to your destination: A route that has few stops and allows you to go between 40-45mph will give you the best mileage.
2. Use cruise control: If you’re driving on long stretches of semi-flat terrain, cruise control helps save fuel by keeping your car at a constant speed. It also helps your engine by assisting it in regulating the temperature since less combustions will be happening within. Using cruise control over hilly terrain is inefficient, as your vehicle works overtime to maintain speed.
3. Make sure your tires are properly inflated: If they’re under-inflated, fuel expenditure may rise by as much as 6%.
4. Coast when possible: Not applying your foot to the gas allows your vehicle to run without using gas or your hybrid battery.
5. Keep your hybrid battery healthy: If you notice any of a failing battery’s symptoms, get it checked as soon as possible. A new or refurbished hybrid battery doesn’t have to break the bank – many replacement options are not only cost-effective but are built to be more efficient, such as these Prius hybrid battery replacements.

    

To read more about your vehicle’s hybrid battery and how to check that it’s running in tip-top shape, head to this blog: How Long Do Hybrid Batteries Last?