2001 TOYOTA PRIUS battery

CHASSIS ± P111 HYBRID TRANSAXLE
182CH14
182CH13
HV Battery
Inverter
Drive
MG2 MG1
Discharge
Recharging
Electrical Path
Generation
Engine : Flow of
: motive force
: Flow of
: electrical force
Sun Gear Carrier Ring Gear
rpm
MG1 Engine MG2: Torque
: Driving Load
: MG2 Torque
Nomographic Chart of Planetary
Gear Unit
182CH18
182CH17
Inverter
HV Battery
MG2MG1
Speed
Control
Engine
Recharging
Electrical Path
Generation: Flow of
: electrical force
Sun Gear Carrier Ring Gear
MG1 Engine MG2: Driving
: Load
: MG2
: Torque
Nomographic Chart of Planetary
Gear Unitrpm Speed
Control : Flow of
: motive force 84
4) Normal Traveling
When the vehicle is being driven under normal traveling condition, the motive force of the engine is divided
by the planetary gears. A portion of this motive force is output directly, and the remaining motive force
is used for generating electricity through MG1. Through the use of an electrical path of an inverter, this
electrical force is sent to MG2 to be output as the motive force of MG2. Under further high-load conditions,
the electrical force from the HV batteries is also used as a motive force of MG2.
5) Deceleration Driving
If the SOC of the HV batteries is within the specified value during deceleration, electricity is generated
by MG2 to recharge the HV batteries. If the SOC is excessive, the apportionment of energy to the hydrau-
lic brakes is increased. However, if the shift lever is in position B, the engine is started by MG1 in order
to apply the engine brake.

CHASSIS ± P111 HYBRID TRANSAXLE
182CH20
182CH19
Inverter
HV Battery
MG2MG1
Engine
Discharge
Electrical Path
Recharging
GenerationDrive: Flow of
: motive force
: Flow of
: electrical force
Sun Gear Corrier Ring Gear
rpm
MG1 Engine MG2: Driving Load
: MG2 Torque
Nomographic Chart of Planetary
Gear Unit
NOTICE
Because it is not possible for this transaxle to separate the MG2 output force from the drive wheels when
the shift lever is in position N, the generation of electricity is disabled. In this condition, the generation
of electricity could cause the motive force to be transmitted, which creates a hazardous situation. There-
fore, beware that the HV batteries could become discharged in this state.85
6) Reverse Driving
The vehicle drives in reverse powered only by MG2. If the SOC of the HV batteries exceeds the specified
value, the vehicle drives powered only by MG2. If the SOC is below the specified value, the engine starts,
and the electrical force generated by MG1 passes through the electrical path function of the inverter in
order to be used as the motive force of MG2.

CHASSIS ± BRAKES
182CH44
Front
Brake ActuatorRear
Hydraulic
Brake
Differential
Gear
Stroke
Simulator
Hydraulic
Adjustment Area
ABS Function AreaHydraulic
Brake
MG2
MG1Inverter
EngineHV Battery
THS (TOYOTA Hybrid System) Regenerative
Brake
Switching
Valve
Power Splitting
Device
182CH45
Combination Meter
Brake ECU
Brake Warning Buzzer
Rear Wheel
Speed Sensors
and Rotors
Hydraulic Brake Booster
(Master Cylinder Portion)
Front Wheel Speed
Sensor and Rotor
Brake Actuator HV ECU
Hydraulic Brake
Booster
Power Supply
portion
Solenoid RelayReservoir
Tank
ECMPump
Motor Relays 104
BRAKE SYSTEM
1. General

A brake system, which uses brake fluid that is stored under high pressure to assist the brake pedal effort
and to operate the ABS with EBD control and the regenerative brake cooperative control, has been adopted.

A regenerative brake system, which uses the MG2 that is used for driving the vehicle as a generator to effi-
ciently convert the energy that is created during braking, has been adopted. This system enables to collect
more driving energy by having the control to cooperate the hydraulic brake and the regenerative brake.
2. System Diagram
3. Layout of Main Components

CHASSIS ± BRAKES
182CH55
Speed Sensors
Combination Meter
Speedometer
ABS Warning Light
Brake System Warning
Light
Brake Warning Buzzer
Stop Light Switch
ECM
HV ECU
Inverter
Battery ECU
Brake
ECU
Solenoid Relay
Motor Relay
Brake Actuator
ABS Solenoid
Valves
Switching Solenoid Valve
Linear Solenoid Valve
Master Cylinder Pressure
Sensor
Regulator Pressure Sensor
Front Wheel Pressure Sensor
Rear Wheel Pressure Sensor
Pump Motor
High Pressure Switch
Low Pressure Switch
Reservoir Level Switch
Hydraulic Brake Booster11 5
Brake ECU
1) General
Based on the signals received from the sensors the communication it maintains with the HV ECU, the
brake ECU effects conventional brake control, ABS with EBD control, and regenerative brake coopera-
tive control.
2) Fail Safe
If a malfunction occurs in the brake ECU, in the input signals from the sensors, or in actuator system,
this function prohibits the current from flowing to the brake actuator.
As a result, the solenoids in the brake actuator turn off, enabling the braking force of the hydraulic brake
to take effect. Furthermore, by illuminating the ABS warning light or the brake system warning light,
this function alerts the driver that a malfunction exists in the system.
Only if the regenerative brake system cannot be used, such as in the case of a malfunction in the commu-
nication with the HV ECU, this function switches controls to enable the hydraulic brake to generate the
entire brake force.
3) Warning Light Check Function
The ABS warning light and brake system warning light turns on for about 3 seconds after the ignition
switch is turned on to check the circuit.

CHASSIS ± BRAKES
Battery
Acceptance
Capacity
182CH58
Braking
Force
Regenerative
Braking ForceHydraulic
Braking Force
Vehicle SpeedRegenerative
Braking ForceHydraulic
Braking Force
Time
Changes in Regenerative Braking Force Changes in Braking Force Apportionment
Braking
Force
Driver's DemandDriver's Demand 11 8
2) Regenerative Brake Cooperative Control
a. General
The regenerative brake cooperative control uses the switching valves and linear solenoid valves to regu-
late the hydraulic pressure that is supplied to the wheel cylinders. It also operates cooperatively with
the regenerative braking force that is generated in the MG2 in accordance with the master cylinder pres-
sure.
b. Apportioning of the Brake Force
The apportioning of the brake force between the hydraulic brake and the regenerative brake varies by
the vehicle speed and time.
The apportioning of the brake force between the hydraulic brake and the regenerative brake is con-
trolled so that the total brake force of the hydraulic brake and the regenerative brake matches the brake
force that the driver requires.

Imagery Drawing 
c. Operation
Regenerative brake cooperative control is executed when the vehicle is driven in the shift position ªDº
or ªBº.
The master cylinder pressure that is generated when the driver presses on the brake pedal is detected
by the pressure sensor, and the brake ECU calculates the brake force request factor. A portion of the
brake force request factor is transmitted to the HV ECU in the form of a regenerative brake activation
request factor. The HV ECU executes generative braking by commanding the electric motor to generate
negative torque.
The brake ECU controls the opening of the linear solenoid valves, which are used for increasing / de-
creasing the hydraulic pressure, to regulate the wheel cylinder hydraulic pressure in relation to the mas-
ter cylinder hydraulic pressure, thus compensating for the brake force that is not provided sufficiently
by the regenerative brake.
While the regenerative brake cooperative control is being prohibited due to an abnormality in the sys-
tem, or when the shift lever is in a position other than D or B, the regenerative braking force is not gener-
ated. At this time, only the hydraulic braking force is applied by turning ON (opening) the linear sole-
noid valve SLA and turning OFF (closing) the SLR.

BODY ELECTRICAL
BODY ELECTRICAL ± BATTERY AND MULTIPLEX COMMUNICATION SYSTEM
182BE01
: BEAN : UART
: AVC-LAN : Serial Data
Link
Brake ECU
HV ECU
Air Condi-
tioning ECU
Meter ECU
ECM
Body ECU
Display ECU
Audio
ComponentsGateway
ECU
Power Window
Master SwitchDoor Con-
trol ReceiverBattery ECU
141
AUXILIARY BATTERY
DESCRIPTION
All the body electrical systems and auxiliary equipment operate using the same 12 V battery used on ordinary
gasoline engine vehicles.
However, as the battery structure is different, Prius uses an exclusive battery. See page 42 in the THS (TOYOTA
Hybrid System) section for details of the auxiliary battery structure.
MULTIPLEX COMMUNICATION SYSTEM
DESCRIPTION
A multiplex communication system has been adopted for body electrical system control and to achieve
a slimmer wiring harnesses configuration.
BEAN (Body Electronics Area Network) has been adopted between the body ECU, ECM, meter ECU,
air conditioning ECU, and the gateway ECU. Furthermore, AVC-LAN (Audio Visual Communication-
Local Area Network) has been adopted between the display ECU and the audio components.
The conversion of communication signals between BEAN and AVC-LAN is performed by the gateway
ECU.
UART (Universal Asynchronous Receiver Transmitter), which performs unidirectional communication,
has been adopted between the body ECU and the power window master switch.
A serial data link has been adopted between the body ECU and the door control receiver. In addition, a
serial data link has been adopted between the ECM, HV ECU, brake ECU, and the battery ECU, which
pertain to the control of the hybrid system.

System Diagram 

BODY ELECTRICAL ± LIGHTING
151LBE68151LBE67
Multi-Reflector Type HeadlightConventional Headlight Reflector
(Multiple Parabolic Shape)
Headlight Bulb
Headlight Bulb
Lens
Light DistributionReflector
(Rotating Parabolic Shape)
Headlight Bulb
Lens Cut
Lens
Light Distribution
182BE03
From
BatteryDimmer Relay
Headlight
Relay
Parking
Brake Switch
H-LP DIM
PKBDaytime
Running
Light Relay
DRL
From
BatteryEH
HILO HI
LO
No.4
Daytime
Running
Light Relay
144
LIGHTING
HEADLIGHTS
The prius has newly adopted the multi-reflector headlights. Conventional headlights accomplish the dispersion
and distribution of the light that is emitted by the bulbs through the lens cut pattern. However, with the multi-reflec-
tor type headlights, the light from the bulbs is dispersed and distributed through multiple parabolic shaped reflec-
tors. As a result, the lens cut pattern is no longer provided in the center of the lens, thus realizing a clear look.

Light Distribution Diagram 
DAYTIME RUNNING LIGHT SYSTEM
The daytime running light system is adopted for Canada model as standard and U.S.A. model as optional
equipment. This system is designed to automatically activate the headlights (dimmed low beams) during the
daytime to keep the car highly visible to other vehicles.
This system is controlled by a semi-conductor relay circuit (daytime running light relay).

BODY ELECTRICAL ± AIR CONDITIONING
182BE17
PTC Heaters
182BE18
ALT AM1Ignition
Switch
HTR
MAIN
PS
HTR1PTC
HTR1PTC
HTR2
Battery
Heater Core
Integrated
PTC HeaterPTC Heaters
IG
HTR0
Air
Conditioning
ECU
HTR2
GNDMPX
IDH
Switch Signals from
Heater Control Panel
ECM
Body
ECU
Converter
Ambient
Temperature Sensor
Engine Coolant
Temperature Sensor
156
PTC heaters have been provided in the air
duct at the footwell outlet in front of the air
conditioning unit. However, air condition-
ing without the PTC heaters is offered as an
option on the U.S.A. models.
This PTC heater, which is a honeycomb-
shaped PTC thermistor, directly warms the
air that flows in the duct.

Wiring Diagram