airbag TOYOTA PRIUS 2001 Service Owner's Manual

ENGINE ± 1NZ-FXE ENGINE
182EG39
Front Airbag
Sensors
(RH and LH)Airbag
Sensor
AssemblyHV
ECUCircuit
Opening
Relay
Fuel Pump
Motor ECM73
7. Fuel Pump Control
A fuel cut control is adopted to stop the fuel pump when the SRS airbag is deployed, thus helping reduce fuel
leakage.
In this system, the airbag deployment signal from the airbag sensor assembly is detected by the HV ECU,
send the signal to ECM, which turns OFF the circuit opening relay.
After the fuel cut control has been activated, turning the ignition switch from OFF to ON cancels the fuel cut
control, thus engine can be restarted.

THS (TOYOTA HYBRID SYSTEM)27
THS CONTROL SYSTEM
1. General
The THS control system contains the following components:
HV (Hybrid Vehicle
Control) ECU
Controls the MG1, 2 and the engine according to the demand torque,
regenerative brake control and the SOC (state of charge) of HV battery. These
factors are determined by the shift position, the degree which the accelerator
is depressed, and vehicle speed.
ECM
ControlThe HV ECU receives engine status data (rpm, torque) from the ECM and
determines the engine demand torque.
Moreover, engine stop and fuel cut signals are sent according to the driving
conditions.
In addition, the vehicle speed signal received from the combination meter is
also sent.
BRAKE
ECU
ControlThe HV ECU receives data corresponding to the total braking force needed.
The HV ECU transmits the regeneration brake demand torque valve, as well
as the regeneration brake execution torque valve.
Inverter
(for MG1,
MG2)
ControlThe HV ECU sends the signal to the power transistor in the inverter for
switching the U, V, W, phase of the MG1, 2 in order to drive the MG1 and 2.
Moreover, if an overheating, overcurrent or fault voltage signal is received
from the inverter, it is shut down.
ConverterWhen a malfunction is in the Hybrid vehicle control system, the HV ECU
sends a signal to the converter, and the converter is stopped.
MG1, MG2Detects the position of the rotor of the MG1, 2 and controls the current flowing
to the MG1, 2.
In addition, the temperature is detected and the maximum load is controlled.
Battery ECUReceives the SOC of the HV battery and the current value.
Airbag Sensor
AssemblyReceives the airbag deployment signal.
A / C ECUReceives the engine power rise demand (when air-conditioning is turned ON)
and the engine running demand for water-temperature maintenance.
Accelerator Pedal
Position SensorReceives the value corresponding to degree at which the accelerator pedal is
depressed.
Shift Position SensorReceives the shift position signal (P, R, N, D, B).
Cruise Control SwitchReceives the cruise control switch signal.
Stop Light SwitchReceives the brake signal.
Interlock Switch
(for Inverter Cover and
Service Plug)Verifies that the cover of both the inverter and the service plug have been
installed.
Circuit Breaker SensorThe high-voltage circuit is intercepted if a vehicle collision has been detected.
DiagnosisWhen the HV ECU detects a malfunction, the HV ECU diagnosis and
memorizes the values corresponding to the failure.
Fail-SafeWhen the HV ECU detects a malfunction, the HV ECU stops or controls the
actuators and ECUs according to the data already stored in memory.

THS (TOYOTA HYBRID SYSTEM)
M-UU,
VU, WU
M-SDOWN
G-UU,
VU, WU
CONT 3
SENSORS ACTUATORS
INVERTER (for MG1)
INVERTER (for MG2)
G-SDOWN
DATA LINK CONNECTOR 3 SIL, TC
IGCT RELAYAUXILIARY
BATTERY MRELBATT
BATTERY ECU
ABS ECU
VEHICLE SPEED SIGNAL
(for Hybrid Transaxle)
ACCELERATOR PEDAL
POSITION SENSOR
SHIFT POSITION SENSOR
CRUISE CONTROL SWITCH
AIRBAG SENSOR ASSEMBLY
CIRCUIT BREAKER SENSOR
INTERLOCK SWITCH
(for Inverter Cover and Service Plug)
STOP LIGHT SWITCH
A / C ECU
CONVERTER NODD
MG2
M-REF,
SIN, COS
MG1
G-REF,
SIN, COS
ECM
COMBINATION METER

Vehicle Speed Signal SPD
INVERTER
(for MG1)
INVERTER
(for MG2)
CONT 2
SYSTEM MAIN RELAY NO.1
SYSTEM MAIN RELAY NO.2
SYSTEM MAIN RELAY NO.3
G-MOTT
M-MOTT
CONT 1
HV ECU
HTD, DTH
HTB, BTH
VPA1, 2
SFT, P, R,
N, D, B
CCS
ABFCS
ACS
ILK
STP EGON
HTE, ETH
ACON
G-INVT
G-IU, IV, IW
M-SINV, FINV
M-INVT
M-IU, IV, IW
GO
SPDO
ESTP
IB
G-SINV, FINV
MG1
MG2
28
2. Construction
The configuration of the THS control system in the Prius is shown in the following chart.

CHASSIS ± STEERING
182CH66
182CH67
Instrument Panel
Reinforcement
Main ShaftInstrument Panel
Reinforcement
Energy Absorbing Plate
Breakaway Bracket
DetachSecondary
Collision
Primary
CollisionContractDeform
After Collision
Before Collision129
ENERGY ABSORBING MECHANISM
The energy absorbing mechanism in the steering column consists of a lower bracket, breakaway bracket, en-
ergy absorbing plate and a contractile main shaft. The steering column is mounted onto the instrument panel
reinforcement via a lower bracket and breakaway bracket which is supported via a capsule and energy absorb-
ing plate. The steering column and the steering gear box are connected with a contractile intermediate shaft.
Operational examples of this mechanism are follows.
When the steering gear box moves during a collision (primary collision), the main shaft and the intermediate
shaft contract, thus reduce the chance that the steering column and the steering wheel protrude into the cabin.
When an impact is transmitted to the steering wheel in a collision (secondary collision), the steering wheel
and the driver airbag help absorb the impact. In addition, the breakaway bracket and the lower bracket sepa-
rate, causing the entire steering column to move forward.
At this time, the energy absorbing plate becomes deformed to help absorb the impact of the secondary collision.

BODY ± ENHANCEMENT OF PRODUCT APPEAL
182BO16
Gas Pressure from
the Gas Generator
RackBobbinSeat Belt
Planetary Gear
Pinion GearClutch Mechanism
139
SEAT BELT
1. General

The front seats are provided with an electrical sensing type seat belt pretensioner and a seat belt force limit-
er. In the beginning of a collision, the seat belt pretensioner instantly pulls up the seat belt thus providing
the excellent belt's effectiveness in restraining the occupant.
When the impact of a collision causes the tension of the seat belt applied to the occupant to reach a predeter-
mined level, the force limiter restrains the tension, thus controlling the force applied to the occupant's chest
area.

In accordance with the ignition signal from the airbag sensor assembly, the seat belt pretensioner activates
simultaneously with the deployment of the SRS airbags for the driver and front passenger.

The passenger seats are provided with ALR (Automatic Locking Retractor) / ELR (Emergency Locking
Retractor) seat belts.
2. Seat Belt Pretensioner
General
The pretensioner mechanism mainly consists of a rack, pinion gear, planetary gear, clutch mechanism, and
a bobbin.
During the deployment of this pretensioner mechanism, the gas pressure from the gas generator pushes the
rack down and retracts the seat belt via the pinion gear, planetary gear, clutch mechanism, and bobbin.

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 

BO4111
Negative Cable
± INTRODUCTIONFOR ALL OF VEHICLES
IN±21
21 Author: Date:
2001 PRIUS (RM778U)
7. FOR VEHICLES EQUIPPED WITH SRS AIRBAG AND
SEAT BELT PRETENSIONER
(a) The PRIUS is equipped with an SRS (Supplemental Re-
straint System), such as the driver airbag, front passen-
ger airbag assembly, side airbag assembly and seat belt
pretensioner.
Failure to carry out service operations in the correct se-
quence could cause the supplemental restraint system to
unexpectedly deploy during servicing, possibly leading to
a serious accident.
Further, if a mistake is made in servicing the supplemental
restraint system, it is possible the SRS may fail to operate
when required. Before servicing (including removal or
installation of parts, inspection or replacement), be sure
to read the following items carefully, then follow the cor-
rect procedure described in this manual.
(b) GENERAL NOTICE
(1) Malfunction symptoms of the supplemental re-
straint system are difficult to confirm, so the diag-
nostic trouble codes become the most important
source of information when troubleshooting. When
troubleshooting the supplemental restraint system,
always inspect the diagnostic trouble codes before
disconnecting the battery (See page DI±497).
(2) Work must be started after 90 seconds from the
time the ignition switch is turned to the ºLOCKº posi-
tion and the negative (±) terminal cable is discon-
nected from the battery.
(The supplemental restraint system is equipped
with a back±up power source so that if work is
started within 90 seconds of disconnecting the neg-
ative (±) terminal cable from the battery, the SRS
may deploy.)
When the negative (±) terminal cable is discon-
nected from the battery, memory of the clock and
audio systems will be cancelled. So before starting
work, make a record of the contents memorized by
the each memory system. Then when work is fin-
ished, reset the clock and audio systems as before.
To avoid erasing the memory of each memory sys-
tem, never use a back±up power supply from anoth-
er battery.

F08459
Marks
IN±22
± INTRODUCTIONFOR ALL OF VEHICLES
22 Author: Date:
2001 PRIUS (RM778U)
(3) Even in cases of a minor collision where the SRS
does not deploy, the steering wheel pad, front pas-
senger airbag assembly, side airbag assembly and
seat belt pretensioner should be inspected (See
page RS±14, RS±28, RS±63 and BO±92).
(4) Never use SRS parts from another vehicle. When
replacing parts, replace them with new parts.
(5) Before repairs, remove the airbag sensor if shocks
are likely to be applied to the sensor during repairs.
(6) Never disassemble and repair the airbag sensor as-
sembly, steering wheel pad, front passenger airbag
assembly, side airbag assembly or seat belt preten-
sioner.
(7) If the airbag sensor assembly, steering wheel pad,
front passenger airbag assembly, side airbag as-
sembly or seat belt pretensioner has been dropped,
or if there are cracks, dents or other defects in the
case, bracket or connector, replace them with new
ones.
(8) Do not directly expose the airbag sensor assembly,
steering wheel pad, front passenger airbag assem-
bly or seat belt pretensioner to hot air or flames.
(9) Use a volt/ohmmeter with high impedance (10 kW/V
minimum) for troubleshooting of the electrical cir-
cuit.
(10) Information labels are attached to the periphery of
the SRS components. Follow the instructions on the
notices.
(11) After work on the supplemental restraint system is
completed, check the SRS warning light (See page
DI±497).
(c) SPIRAL CABLE (in Combination Switch)
The steering wheel must be fitted correctly to the steering
column with the spiral cable at the neutral position, other-
wise cable disconnection and other troubles may result.
Refer to SR±14 of this manual concerning correct steer-
ing wheel installation.

B04764
Example:
Correct Wrong
Z13950
Example:
± INTRODUCTIONFOR ALL OF VEHICLES
IN±23
23 Author: Date:
2001 PRIUS (RM778U)
(d) STEERING WHEEL PAD (with Airbag)
(1) When removing the steering wheel pad or handling
a new steering wheel pad, it should be placed with
the pad top surface facing up.
Storing the pad with its metallic surface facing up-
ward may lead to a serious accident if the airbag de-
ploys for some reason. In addition do not store a
steering wheel pad on top of another one.
(2) Never measure the resistance of the airbag squib.
(This may cause the airbag to deploy, which is very
dangerous.)
(3) Grease should not be applied to the steering wheel
pad and the pad should not be cleaned with deter-
gents of any kind.
(4) Store the steering wheel pad where the ambient
temperature remains below 93°C (200°F), without
high humidity and away from electrical noise.
(5) When using electric welding, first disconnect the air-
bag connector (yellow color and 2 pins) under the
steering column near the combination switch con-
nector before starting work.
(6) When disposing of a vehicle or the steering wheel
pad alone, the airbag should be deployed using an
SST before disposal (See page RS±16).
Carry out the operation in a safe place away from
electrical noise.

B02420
Example:
Correct Wrong
Z13951
Example:
IN±24
± INTRODUCTIONFOR ALL OF VEHICLES
24 Author: Date:
2001 PRIUS (RM778U)
(e) FRONT PASSENGER AIRBAG ASSEMBLY
(1) Always store a removed or new front passenger air-
bag assembly with the airbag deployment direction
facing up.
Storing the airbag assembly with the airbag deploy-
ment direction facing down could cause a serious
accident if the airbag inflates.
(2) Never measure the resistance of the airbag squib.
(This may cause the airbag to deploy, which is very
dangerous.)
(3) Grease should not be applied to the front passen-
ger airbag assembly and the airbag door should not
be cleaned with detergents of any kind.
(4) Store the airbag assembly where the ambient tem-
perature remains below 93°C (200°F), without high
humidity and away from electrical noise.
(5) When using electric welding, first disconnect the air-
bag connector (yellow color and 2 pins) installed on
the assembly before starting work.
(6) When disposing of a vehicle or the airbag assembly
alone, the airbag should be deployed using an SST
before disposal (See page RS±30).
Perform the operation in a safe place away from
electrical noise.