service TOYOTA PRIUS 2001 Service Service Manual

ENGINE ± 1NZ-FXE ENGINE45
FEATURES OF 1NZ-FXE ENGINE
The 1NZ-FXE engine has been able to achieve the following performance through the adoption of the items
listed below.
(1) High performance and fuel economy
(2) Low noise and vibration
(3) Lightweight and compact design
(4) Good serviceability
(5) Clean emission
Item
(1)(2)(3)(4)(5)1NZ-FE
The VVT-i system is used.
High-expansion Atkinson cycle has been adopted.
An offset crankshaft has been adopted.
A cylinder block made of aluminum has been adopted.
A stainless steel exhaust manifold is used for weight reduction.
A rearward exhaust layout has been adopted to realize the early
activation of the catalyst.
HC Adsorber and catalyst system has been adopted.
Fuel returnless system has been adopted.
12-hole type fuel injectors have been adopted.
The DIS (Direct Ignition System) makes ignition timing
adjustment unnecessary.
Quick connectors are used to connect the fuel hose with the
fuel pipes.
The oil filter is installed diagonally downward.
A timing chain has been adopted.
A vacuum system that detects leaks in the evaporative
emission control system has been adopted.
The vapor reducing fuel tank system has been adopted.
This system reduces the amount of fuel vapor that is generated.

ENGINE ± 1NZ-FXE ENGINE
171EG13
Spring
Plunger
Cam
Cam Spring Check Ball
171EG32171EG31
Service Hole for
Chain Tensioner
Oil Pump
Front ViewBack View51
5. Chain Tensioner
The chain tensioner uses a spring and oil pres-
sure to maintain proper chain tension at all
times.
The chain tensioner suppresses noise generated
by the chain.
A ratchet type half-back mechanism is used.
6. Timing Chain Cover
A single-piece, aluminum die-cast timing chain cover that entirely seals the front portion of the cylinder
block and the cylinder head has been adopted.
A service hole for the chain tensioner has been provided in the timing chain cover to improve serviceabili-
ty.

ENGINE ± 1NZ-FXE ENGINE
182EG38
Injector
Delivery Pipe
Pressure Regulator
Fuel Tank Fuel Filter
Fuel Pump 58
FUEL SYSTEM
1. Injector
A compact 12-hole type injector has been adopted to improve the atomization of fuel.
2. Fuel Returnless System
This system is to reduce the evaporative emission. As shown below, integrating the pressure regulator and
fuel filter with the fuel pump assembly made it possible to discontinue the return of fuel from the engine area
and prevent temperature rise inside the fuel tank.
3. Quick Connector
Quick connector has been adopted to connect the fuel pipe with the fuel hose to improve serviceability.

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)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)
182TH34
Battery Pack Upper Case
Service Plug
SMR
(System Main Relay)Battery ECU
HV Battery Module37
HV BATTERY
DESCRIPTION
The sealed nickel metal hydride (Ni-MH) battery technology has been further evolved in the newly devel-
oped HV battery that offers features such as high power density, lightweight, and longevity, that are specifi-
cally designed to match the characteristics of the THS. Because the THS effects charge / discharge control
to maintain a constant level of SOC (state of charge) while the vehicle is operating normally, it does not rely
on the use of external rechargers.
In the battery area, six 1.2-volt cells are connected in series to form one module. A total of 38 modules are
divided into two holders and connected in series. Thus, the HV battery containing a total of 228 cells has a
rated voltage of 273.6 V.
The electrode plates in the HV battery are made of materials such as porous nickel and metal hydride alloy.

THS (TOYOTA HYBRID SYSTEM)
Battery Voltage for Each
Module
HV Battery Temp. Sensor
Temp. Sensor (Circumference)
Amperage sensor
A / C Signal
Battery ECU
A / C ECU
HV Battery Cooling Fan
HV ECU
Amperage Signal
Total Voltage Signal
Charge or Discharge Signal
DiagnosisData Link Connector 3
182TH11
HV Battery
SMR2
Battery Module
(7.2 V x 19)
Service Plug
High-Voltage Fuse
Battery Module
(7.2 V x 19)
SMR3
Resistor SMR1
38
HV BATTERY CONTROL SYSTEM
DESCRIPTION
To maintain the battery at a proper SOC (state of charge), and to ensure safety in the event that the HV battery
malfunctions, the battery ECU features the following control functions:

System Diagram 
CONSTRUCTION
The HV battery, battery ECU, and SMR (sys-
tem main relay), are enclosed in a single case
and placed in the luggage compartment behind
the rear seat to make more effective use of ve-
hicle space.
In the battery area, six 1.2-volt cells are con-
nected in series to form one module. A total of
38 modules are connected in series.
Thus, the HV battery containing a total of 228
cells has a rated voltage of 273.6 V.
A service plug that shuts off the circuit is pro-
vided in the middle of the 38 modules. Before
servicing any portion of the high-voltage cir-
cuit, make sure to remove the service plug. For
further details, refer to the 2001 Prius Repair
Manual (Pub No. RM778U).

THS (TOYOTA HYBRID SYSTEM)
182TH11
HV Battery
SMR 2
SMR 1
Battery Module
(7.2 V x 19)
Resistor
Service Plug
High-Voltage Fuse
Battery Module
(7.2 V x 19)
SMR 3
182TH30
Service Plug 40
2. SMR (System Main Relay)
The SMR is a relay that connects and disconnects
the power source of the high-voltage circuit upon
receiving a command from the HV ECU. A total
of 3 relays, one for the negative side, and two for
the positive side, are provided to ensure proper op-
erations.
At the time of connection, SMR1 and SMR3 are
turned ON; after this, SMR2 is turned ON and
SMR1 is turned OFF. By allowing the controlled
current via the resistor to pass through initially in
this manner, the circuit is protected against rush
current.
At the time of disconnection, SMR2 and SMR3
are turned OFF in that order, and the HV ECU ver-
ifies that the respective relays have been properly
turned OFF.
3. Service Plug
By removing the service plug before performing any inspection or service, the high-voltage circuit is shut
off at the intermediate position of the HV battery, thus ensuring safety during service.
The service plug assembly contains a reed switch for interlock. Lifting the clip lock up turns OFF the reed
switch, which shuts off the SMR. However, to ensure safety, make sure to turn OFF the ignition switch before
removing the service plug. For further details on how to handle the service plug, refer to the 2001 Prius Repair
Manual (Pub No. RM778U). The main fuse for the high-voltage circuit is provided inside of the service plug
assembly.