O2 sensor TOYOTA PRIUS 2001 Service Manual PDF

THS (TOYOTA HYBRID SYSTEM)
182TH19
EngineECMHV ECU
Shift Position Sensor
Brake ECU
HV Battery
Accelerator Pedal Position Sensor
Hybrid Transaxle Inverter with Converter
Battery ECU
SMR (System Main Relay)
Service Plug23

FEATURES OF THS
This system controls the following modes in order to achieve the most efficient operations to match the driv-
ing conditions:
1. Supply of electrical power from the HV battery to MG2 provides force to drive the wheels
2. While the tires are driven by the engine via the planetary gears, MG1 is driven via the planetary gears to
supply electricity to MG2 to drive the wheels
3. When the vehicle is decelerating, kinetic energy from the wheels is recovered and converted into electrical
energy and used to recharge the HV battery by means of MG2.
The HV ECU switches between these modes (1, 2, 1 + 2, or 3) according to the driving conditions. However,
when the SOC of the HV battery is low, the HV battery is charged by the engine by turning MG1.
As a result, it achieves far greater the fuel economy compared to conventional gasoline engine vehicles, at
a reduced level of exhaust gas emissions. Furthermore, this revolutionary powertrain has eliminated the
constraints that are associated with electric vehicles (such as their short cruising range or their reliance on
external recharging units).

LAYOUT OF MAIN COMPONENTS

THS (TOYOTA HYBRID SYSTEM) 24

MAIN FUNCTIONS OF COMPONENTS
MG1Generates high-voltage electricity by being powered primarily by the engine.
Also functions as a starter to start the engine.
Hybrid
Trans-
axle
MG2
Primarily provide additional power to the engine in order to increase the
overall drive force. During braking, or when the accelerator pedal is not
depressed, it generates electricity to recharge the HV battery (Regenerative
brake system).
Planetary
Gear UnitDistributes the engine's drive force as appropriate to directly drive the vehicle
as well as the generator.
HV Battery
Supplies electric power to the MG2 during start-off, acceleration, and uphill
driving; recharged during braking or when the accelerator pedal is not
depressed.
InverterA device that converts the high-voltage DC (HV battery) into AC (MG1 and
MG2) and vice versa (Converts AC into DC).
Converter
Drops the high-voltage direct current (DC 273.6 V) into DC12 V in order to
supply electricity to body electrical components, as well as to recharge the
auxiliary battery (12 V).
HV (Hybrid Vehicle
Control) ECU
Information from each sensor as well as from the ECU (ECM, Battery ECU,
ABS ECU) is received, and based on this the required torque and output power
is calculated.
The HV ECU sends the calculated result to the actuators and controllers.
ECMSends a throttle open command to the electronically-controlled throttle in
accordance with the engine output request factor received from the HV ECU.
Battery ECUMonitors the charging condition of the HV battery.
Brake ECU
Controls the regenerative brake that is effected by the MG2 and the hydraulic
brake so that the total braking force equals that of a conventional vehicle that
is equipped only with hydraulic brakes.
Also, the brake ECU performs the ABS control conventionally.
Accelerator PedalConverts the accelerator angle into an electrical signal and outputs it to the HVAccelerator Pedal
Position Sensor
Converts the accelerator angle into an electrical signal and outputs it to the HV
ECU.
Shift Position SensorConverts the shift lever position into an electrical signal and outputs it to the
HV ECU.
SMR (System Main
Relay)Connects and disconnects the high-voltage power circuit through the use of
a signal from the HV ECU.
Service plugShuts off the high-voltage circuit of the HV battery when this plug is removed
for vehicle inspection or maintenance.

THS (TOYOTA HYBRID SYSTEM)
Shift Position
Sensor
182TH05
Accelerator
Pedal Position
Sensor
BRAKE
ECU
Shift Position
(Main and Sub)
Accelerator Angle
(Main and Sub)
Regenerative
Request FactorHV ECUInverter
Voltage
SMR Control
MG2MG1
RPMEngine
Power
RequestCharging
Condition,
Amperage
SMRSMR
Amperage
HV
Battery Engine
Planetary Gear
Unit
Wheel
Wheel
ECM
Battery
ECU
Hydraulic
Brake
Actual
Regenerative
Braking Factor
Auxiliary
Battery
Mechanical Power Path
Electrical Signal Hydraulic
Converter
25

SYSTEM DIAGRAM

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.

THS (TOYOTA HYBRID SYSTEM)
HV ECUGO
ECM
Engine
Throttle Control
Motor
SPDO
EF1
HTE, ETH
ESA
VVT-i
W
MESTP
Brake Actuator
(Brake Master
Cylinder)
BRAKE ECUBrake Actuator
(Solenoid Valves)
Pressure Sensors
Signal
HV ECU Pressure
BTH
Total Brake Force
RequestedHTB
Regenerative Brake
Force Transmitted29
3. ECM Control
The ECM receives the demand torque and the target rpm which were sent from HV ECU (THE, ETH), and
controls the degree of throttle valve opening, fuel injection timing, ignition time and VVT-i.
In addition, the actual rpm is sent to the HV ECU with GO, and the speed signal from the hybrid transaxle
is received through HV ECU with SPDO.
When the vehicle is stopped, the HV ECU may send an engine stop (ESTP) command to the ECM to reduce
fuel used.
When a malfunction occurs in the system, the ECM activates MIL via the directions from the HV ECU.
4. BRAKE ECU Control
The brake ECU calculates the total braking force needed, based on the master cylinder pressure in the brake
actuator generated when the driver depresses the brake pedal, and sends this valve to the HV ECU.
The HV ECU computes a part for the regeneration brake force from the total braking force, and sends the
result to the brake ECU.
The HV ECU executes to the minus torque to MG2, and carries out the regenerative brake functions.
The brake ECU controls the brake actuator solenoid valves and generates the wheel cylinder pressure, which
is the regenerative brake force subtracted from the total braking force.

THS (TOYOTA HYBRID SYSTEM)
HV ECUG-SDOWNInverter
(for MG1)
MG1
MG2
M-UU, VU, WUSwitching Signal
Switching Signal
G-SIN, COS
M-SIN, COS
Inverter
(for MG2) G-UU, VU, WU
M-SDOWN
G-REF
M-REF
30
5. Inverter Control (for MG1, MG2)
The HV ECU transmits a signal to the power transistor in the inverter (G-UU, VU, WU, M-UU, VU, WU)
for switching the U, V, W phase of the stator coil of MG1 and MG2, based on the rotor position information
sent from MG1, 2 (G-SIN, COS, M-SIN, COS) and the SOC of the HV battery sent from the battery ECU.
When shutting down the current to MG1, 2, a signal is sent to the inverter from the HV ECU (G-SDOWN,
M-SDOWN).
Clutchless System
A clutchless system has been adopted to keep the front wheels and MG2 linked mechanically via gears and
a chain. To disengage the drive force in the neutral position, the N position signal from the shift position
sensor turns OFF all the power transistors in the inverter (which connects the MG1 and the MG2) in order
to shut down the operation of the MG1 and the MG2, thus rendering the drive force at the wheels to zero.
In this state, even if the engine is running, the MG1 merely freewheels in the no-load state.
Therefore, if the vehicle is allowed to operate continuously in the N position in a stationary state such as
in heavy traffic, the SOC (state of charge) of the HV battery will continue to drop lower and lower.
6. Battery ECU
The SOC, temperature and the voltage of HV battery are detected by the battery ECU, and this information
is sent to HV ECU.

THS (TOYOTA HYBRID SYSTEM)
182CH05
Stator
Rotor
Speed Sensor (Resolver)
MG1
182CH04
Stator
Rotor
Speed Sensor (Resolver)
MG2
182TH07
N.m
350
300
250
200
150
100
50
0
01000 30002000 50004000 60000 20 40
30
10 kW
Torque
Engine Speed (rpm)Output
Torque
Output
33
MG1 AND MG2 (MOTOR GENERATOR NO.1 AND NO.2)
DESCRIPTION
Both the MG1 and the MG2 are compact, lightweight, and highly efficient alternating current permanent
magnet synchronous type.
Serving as the source of supplemental motive force that provides power assistance to the engine as needed,
the electric motor helps the vehicle achieve excellent dynamic performance, including smooth start-offs
and acceleration. When the regenerative brake is activated, MG2 converts the vehicle's kinetic energy into
electrical energy, which is then stored in the HV battery.
MG1 recharges the HV battery and supplies electrical power to drive MG2. In addition, by regulating the
amount of electrical power generated (thus varying the generator's rpm), MG1 effectively controls the
continuously variable transmission function of the transaxle. MG1 also serves as the starter to start the
engine.

MG2 Specifications 
TypePermanent Magnet
Motor (1CM)
Rated voltage [V]273.6
Maximum output [kW] (rpm)33 / (1040
5600)
Maximum torque [N.m (kgf.m) (rpm)350 / (0
400)
Amperage at maximum torque [A]351
Cooling systemWater-cooled

Performance Curve 

THS (TOYOTA HYBRID SYSTEM)
182TH29
Rotational
Magnetic FieldU PhaseStator Coil
Rotor
Repulsion
W Phase V Phase
: From inverter
: Connected internally in the motor
Attruction
182TH09
Magnetized Side
Coil A
Coil B
Coil C Speed Sensor
(Resolver)Output Side
182TH10
Inverter Power Cable HV Battery
Junction
BlockPortion routed through
the center floorAuxiliary
Battery
Under-
the-Floor
Reinforcement
12 V
Power Cable
Voltage 
Power Cable
Voltage

34
1. Permanent Magnet Motor
When a three-phase alternating current is passed
through the three-phase windings of the stator
coil, a rotational magnetic field is created in the
electric motor. By controlling this rotating mag-
netic field according to the rotor's rotational posi-
tion and speed, the permanent magnets that are
provided in the rotor become attracted by the ro-
tating magnetic field, thus generating torque.
The generated torque is for all practical purposes
proportionate to the amount of current, and the
rotational speed is controlled by the frequency of
the alternating current.
Furthermore, a high level of torque, all the way to
high speeds, can be generated efficiently by prop-
erly controlling the rotating magnetic field and the
angles of the rotor magnets.
2. Speed Sensor (Resolver)
This is an extremely reliable and compact sensor
that precisely detects the magnetic pole position,
which is indispensable for ensuring the efficient
control of MG1 and MG2.
The sensor's stator contains 3 coils as illustrated, and
output coils B and C are electrically staggered 90 de-
grees. Because the rotor is oval, the distance of the
gap between the stator and the rotor varies with the
rotation of the rotor. Thus, by passing an alternating
current through coil A, output that corresponds to the
sensor rotor's position is generated by coils B and C.
The absolute position can then be detected from the
difference between these outputs.
In addition, the amount of positional variance
within a predetermined time is calculated by the
HV ECU, thus enabling this sensor to be used as
an rpm sensor.
3. Power Cable
The power cable is a high-voltage, high-amperage
cable that connects the HV battery with the inverter,
and the inverter with MG1 and MG2. Starting from
the connector at the left front of the HV battery lo-
cated in the luggage compartment, the power cable
is routed under the rear seat, through the floor panel,
along the under-the-floor reinforcement, and con-
nects to the inverter in the engine compartment. A
shielded cable is used for the power cable in order to
reduce electromagnetic interference.
The 12 V  wiring of the auxiliary battery also
follows the same route.
For identification purposes, the high-voltage wir-
ing harness and connectors are color-coded
orange to distinguish them from those of the ordi-
nary low-voltage wiring.

THS (TOYOTA HYBRID SYSTEM)
182TH26
Inverter
Converter
182TH15
Inverter
HV
Battery
Ignition Signal
Ground
Voltage
Detection
Circuit
Voltage
Detection
Circuit
Bridge Circuit for MG2
Amperage
Sensor
Signal Processor /
Protective Function Processor
Bridge Circuit for MG1
Amperage
Sensor
MG2
HV ECU
MG1
182TH27
Reservoir Tank
Radiator
Water Pump35
INVERTER
1. General
The inverter is an electric power converter that
converts the direct current of the Hybrid vehicle's
high-voltage battery (DC 273.6 V) and the alter-
nating current of the MG1 and MG2.
Consisting of 2 three-phase bridge circuits for
MG1 and MG2, respectively, and each containing
6 power transistors, the inverter converts direct
current and three-phase alternating current. The ac-
tivation of the power transistors is controlled by the
HV ECU. In addition, the inverter transmits in-
formation that is needed for current control, such as
the output amperage or voltage, to the HV ECU.
Together with MG1 and MG2, the inverter is
cooled by the dedicated radiator of the coolant
system that is separate from that of the engine.
2. System Diagram
3. Cooling System
A cooling system via water pump for the inverter
and MG1, 2 has been added.
The HV ECU controls the water pump with cool-
ant temperature.
It is separated with the engine cooling system.