Toyota Prius Owners Manual

Brake system
OPERATION OF INSTRUMENTS ANDCONTROLS / Information before driving your Toyota / Brake system


When the brake is applied, the electricmotor used as a generator converts kineticenergy into electric energy.

The regenerative brake works in the followingoperations.

1. When the accelerator pedal is released,the reduced speed equal to enginebraking in a gasoline−fueled vehicleis obtained in accordance with therunning mode position of the shift lever.

2. When the brake pedal is depressedwith the shift lever in “D” or “B”, theregenerative brake works.


This brake system has 3 independent hydrauliccircuits. If either circuit should fail,the other will still work. However, the pedalwill be harder to press, and your stoppingdistance will increase. Also, thebrake system warning light may come on.


Do not drive your vehicle with only asingle brake system. Have yourbrakes fixed immediately.


The brake actuator uses brake fluid pressurizedby the pump to power−assist thebrakes. If the brake actuator fails duringdriving, the brake system warning lightcomes on and buzzer sounds continuously.In this case, the brakes may not workproperly. If they do not work well, depressthe brake pedal firmly. If the brake systemwarning light comes on, immediately stopyour vehicle and contact your Toyota dealer.

The red and yellow brake system warninglight may stay on for about 60 secondsafter the “IG−ON” mode is enabled. It isnormal if the light turns off after a while.

Depressing the brake pedal repeatedlymay turn on the red and yellow brakesystem warning light and buzzer. It is normalif the light turns off and the buzzerstops sounding after a few seconds.

You may hear a small sound in the enginecompartment after the hybrid system isstarted or the brake pedal is depressedrepeatedly. This is a pump pulsatingsound of the brake system, and it is nota malfunction.

In the following conditions, you may heara motor sound in the engine compartment.

  • The brake pedal is depressed when thehybrid system is turned off.
  • The driver’s door is opened.
  • For a few seconds after the hybridsystem is “OFF” and about 90 secondshave passed.

The brake pedal stroke may be shortwhen you press the “POWER” switch withthe brake pedal depressed.


Do not pump the brake pedal if thehybrid system is not operating.Each push on the pedal uses upyour reserved brake fluid pressure.

Even if the power assist is completelylost, the brakes will stillwork. But you will have to push thepedal hard, much harder than normal.And your braking distance willincrease.


The anti−lock brake system is designedto automatically help prevent lock−up ofthe wheels during a sudden braking orbraking on slippery road surfaces. Thisassists in providing directional stabilityand steering performance of the vehicleunder these circumstances.

Effective way to press the ABS brakepedal: When the anti−lock brake systemfunction is in action, the slip indicator inthe instrument cluster flashes and youwill hear a noise. In this situation, to letthe anti−lock brake system work for you,just hold the brake pedal down morefirmly. Do not pump the brake in a panicstop. This will result in reduced brakingperformance.

The anti−lock brake system becomes operativeafter the vehicle has acceleratedto a speed in excess of approximately 10km/h (6 mph). It stops operating when thevehicle decelerates to a speed belowapproximately 5 km/h (3 mph).Depressing the brake pedal on slipperyroad surfaces such as on a manhole cover,a steel plate at a construction site,joints in a bridge, etc. on a rainy daytends to activate the anti−lock brake system.

When the anti−lock brake system is activated,the following condition may occur.They do not indicate a malfunctionof the system:

You may hear the anti−lock brake systemoperating and the vibrations of thevehicle body and steering wheel. Youmay also hear the motor sound in theengine compartment even after the vehicleis stopped.


Do not overestimate the anti−lockbrake system: Although the anti−lockbrake system assists in providing vehiclecontrol, it is still important todrive with all due care and maintaina moderate speed and safe distancefrom the vehicle in front of you, becausethere are limits to the vehiclestability and effectiveness of steeringwheel operation even with the anti−lock brake system on.

If tire grip performance exceeds itscapability, or if hydroplaning occursduring high speed driving in the rain,the anti−lock brake system does notprovide vehicle control.

Anti−lock brake system is not designedto shorten the stopping distance:Always drive at a moderatespeed and maintain a safe distancefrom the vehicle in front of you.Compared with vehicles without ananti−lock brake system, your vehiclemay require a longer stopping distancein the following cases:

  • Driving on rough, gravel or snow−covered roads.
  • Driving with tire chains installed.
  • Driving over the steps such as thejoints on the road.
  • Driving on roads where the roadsurface is pitted or has other differencesin surface height.

Install all 4 tires of specified size atappropriate pressure: The anti−lockbrake system detects vehicle speedsusing the speed sensors for respectivewheels’ turning speeds. The useof tires other than specified may failto detect the accurate turning speed,resulting in a longer stopping distance.

Toyota Prius: Brake system. Vehicle sold in the U.S.A.

Vehicle sold in the U.S.A.

Toyota Prius: Brake system. Vehicle sold in Canada

Vehicle sold in Canada

“ABS” warning light

The light comes on when the “IG−ON”mode is enabled. If the anti−lock brakesystem works properly, the light turnsoff after the “READY” light comes on.Thereafter, if the system malfunctions,the light comes on again.

When the “ABS” warning light is on (andthe brake system warning light is on), theanti−lock brake system does not operate,but the brake system still operates conventionally.

If any of the following conditions occurs,this indicates a malfunction somewherein the components monitored bythe warning light system. Contact yourToyota dealer as soon as possible toservice the vehicle.

  • The light does not come on when the“IG−ON” mode is enabled, or the“READY” light remains on.
  • The light comes on while you are driving.

A warning light turning on briefly duringoperation does not indicate a problem.


If the “ABS” warning light remains ontogether with the red brake systemwarning light, immediately stop yourvehicle at a safe place and contactyour Toyota dealer.

In this case, not only the anti−lockbrake system function and brake assistfunction will fail but also the vehiclewill become extremely unstableduring braking.

Any of the following conditions may occur,but does not indicate a malfunction:

  • The light may stay on for about 60seconds after the “IG−ON” mode is enabled.It is normal if it turns off aftera while.
  • Depressing the brake pedal repeatedlymay turn on the light. It is normal ifit turns off after a few seconds.


When you slam the brakes on, thebrake assist system judges as an emergencystop and provides more powerfulbraking for a driver who cannot holddown the brake pedal firmly.

When you slam the brakes on, more powerfulbraking will be applied. At this time,you may hear a sound in the enginecompartment. This does not indicate amalfunction.

The brake assist system becomes operativeafter the vehicle has accelerated toa speed in excess of approximately 10km/h (6 mph). It stops operating when thevehicle decelerates to a speed belowapproximately 5 km/h (3 mph).

For an explanation of this system’s warninglight, see “Service reminder indicatorsand warning buzzers” on page 125.

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