2001 TOYOTA PRIUS Service Repair Manual

BODY ELECTRICAL ± ACCESSORIES187
Condition (2)
When the doors, engine hood, and luggage compartment door are all closed and locked, and 30 seconds
have elapsed.
Condition (3)
When one of the doors, engine hood, or luggage compartment door is changed from ªcloseº to ªopenº.
When one of the doors, engine hood, or luggage compartment door is changed from ªlockº to ªunlockº.
When the ignition key is inserted in the ignition key cylinder.
When a terminal is disconnected from the battery and re-connected.
Alert State: a state in which attempted theft can be detected
The system transfers to the alarm state if any one of the conditions (4) listed below is met, or to the non-alert
state if any one of the conditions (5) is met.
Condition (4)
Any door, engine hood, or luggage compartment door is opened.
The ignition key or the wireless door lock remote control system other than the transmitter is used for
unlocking.
The luggage compartment door is opened with something other than the ignition key.
The engine hood is opened.
A terminal is disconnected from the battery and re-connected.
The wiring harness is directly connected as if to turn the ignition switch ON.
Condition (5)
The ignition key is used to unlock the doors or the luggage compartment door.
The transmitter of the wireless door lock remote control system is used to unlock the doors.
The ignition key is inserted in the ignition key cylinder and turned until the ignition switch is ON.
Alarm State: a state in which attempted theft can be detected
When an attempted theft is detected, the system sounds the vehicle's horn and the security horn, flashes
the headlights, taillights, and hazard lights, and illuminates the interior light to alert the people in the area.
If any one of the doors is unlocked, and the ignition key is not inserted in the ignition key cylinder, the
system forcefully locks the doors once.
The system transfers to the alert state if the condition (6) described below is met, or, when the system is
in the alarm state, it transfers to the non-alert state if any one of the conditions (5) described above is met.
At this time, the taillights are illuminated for 2 seconds to inform the driver that an attempted theft has been
detected.
Condition (6)
After approximately 60 seconds of the alarm time have elapsed.

BODY ELECTRICAL ± ACCESSORIES
182BE44
SRS
Warning LightInflator and Bag
for Front Passenger
Front Airbag
Sensor (RH)
Side Airbag
Assembly (RH)
Seat Belt
Pretensioner (RH)
Side Airbag
Sensor (RH) Airbag Sensor
Assembly Seat Belt
Pretensioner (LH) Side Airbag
Sensor (LH) Side Airbag
Assembly (LH)Front Airbag
Sensor (LH)Inflator and Bag
for Driver
182BE45
CollisionImpact
Front Airbag Sensors
Airbag Sensor
Assembly
 Inflator
 (For Driver and Front Passenger)
 Seat Belt Pretensioner
 (LH and RH)
Inflator
(For Right Side or Left Side)
CollisionImpactSide
Airbag
Sensor 188
SRS AIRBAG AND SRS SIDE AIRBAG
The SRS (Supplemental Restraint System) airbags are provided for the driver and front passenger. The
SRS airbags have been designed to help reducing the shocks to the heads and chests of the driver and front
passenger in the event of a frontal impact collision as supplements to the seat belts.
This system is a 3-sensor type airbag system to detect the impact during a front collision using the airbag
sensor assemblies and front airbag sensor, and to make the airbag system and seat belt pretensioner operate
as well.
Also, the function of the ECU to memorize the seat belt wearing condition while inflating the airbag is
added.
The SRS side airbags are provided for the driver and front passenger as an option. The SRS side airbags
have been designed to help reducing the impact energy that is transmitted to the driver and front passenger
in the event of a side collision.
The driver side and the front passenger side are each provided with one sensor.
A fuel cut control has been adopted to stop the fuel pump when the SRS airbag is deployed, thus helping
reduce fuel leakage.

System Diagram 

BODY ELECTRICAL ± ACCESSORIES
182BE46
Cruise Control Switch Signal
Brake Cancel Signal
(Stoplight Switch)
Accelerator Opening Angle Signal
(Accelerator Pedal Position Sensor)
Shift Position Signal
(Sift Position Sensor)
Brake ECUHV ECU
Cruise Control Area

Switch Input Value

Processing

Required Vehicle Speed

Calculation
Hybrid Control Area

Required Torque

Calculation

Drive Force Distribution

between Engine and
Electric Motor
Indicator Light
ECM
Inverter189
CRUISE CONTROL SYSTEM
1. General
The Prius has adopted a cruise control system that uses the hybrid system, and it is offered as an option. This
system, which is controlled by the HV ECU that is integrated with the cruise control ECU, operates the ve-
hicle through an optimal combination of the drive forces of the electric motor and the engine in accordance
with the setting on the cruise control switch.
2. Construction
The cruise control system mainly consists of an HV ECU, cruise control switches, indicator, stoplight switch,
accelerator pedal position sensor, and the shift position sensor.
The table below shows each of the functions.
Item
Function
HV ECUControls all the functions of the cruise control system in accordance with the
signals from the sensors.
Cruise Control Main
SwitchCruise control system's ON / OFF signal requirement.
Cruise Control Switch
A three-directional switch that provides the SET / COAST, RESUME /
ACCEL, and CANCEL functions. It requires the functions and settings in
accordance with its operations.
Indicator LightIt is provided in the combination meter to display whether the system is ON
or OFF.
Stop Light SwitchDetects that the driver has stepped on the brake pedal.
Accelerator Pedal
Position SensorDetects the accelerator pedal opening angle.
Shift Position SensorDetects the shift position.

BODY ELECTRICAL ± ACCESSORIES
182BE47 Warning
Buzzer
(Driver)
Seat Belt
Warning
Light
(Driver)Seat Belt
Warning Light
(Front Passenger Side)
Combination Meter
Seat Belt
Buckle
SwitchOccupant Detection
Sensor
Seat Belt Buckle
Switch
Driver
SideFront Passenger
Side
159BE19 159BE18
182BE53
Occupant Detection Sensor
Front Passenger Seat
Upside ViewSpacerElectrode Sheet
Electrode Sheet
Sensor OFF
Occupant
Sensor ON 190

SEAT BELT WARNING SYSTEM
1. General
A seat belt warning system has been adopted. If the driver's seat belt is not buckled, the warning light flashes
and the buzzer sounds. If the front passenger seat belt is not buckled, it flashes the warning light. When the
ignition switch is turned ON, this system determines whether or not the seat belt is buckled by the ON or OFF
condition of the switch that is provided in the seat belt buckle. The occupant detection sensor provided in
the seat cushion of the front passenger seat determines whether or not an occupant is seated in the front pas-
senger seat.
2. Occupant Detection Sensor
The occupant detection sensor, which is enclosed in the seat cushion of the front passenger seat, is used to
detect whether or not the front passenger seat is occupied.
This sensor, which is shaped as illustrated below, consists of a construction in which two sheets of electrodes
sandwich a spacer. When the occupant is seated, the electrode sheets come in contact with each other through
the hole that is provided in the spacer portion, thus enabling the current to flow.
Thus, the sensor detects whether or not an occupant is seated in the front passenger seat.