2001 TOYOTA PRIUS stop start

2001 PRIUS (EWD414U)
B
The ºCurrent Flow Chartº section, describes which parts each power source (fuses, fusible links, and circuit breakers)
transmits current to. In the Power Source circuit diagram, the conditions when battery power is supplied to each system
are explained. Since all System Circuit diagrams start from the power source, the power source system must be fully
understood.
Theft Deterrent and Door Lock Control
J POWER SOURCE (Current Flow Chart)
11
1
EA1 1EA2 3
7
EB16
E 6
E 7I 2I 2
I 2
E 7
E 7
E 7
2
1
1
2
2
2
2
2
B
B
W W
B B B B BW±B
B
B
B B±O
B±W
W±B
B±W STARTER RELAY INJECTION RELAY15A HAZ±RADIO7.5A AM250A MAIN 1.25B FL MAIN
BATTERY
WWW
W W W
R W±L
W
W
G±W
G
15A TAIL
20A DEFOG
15A RAD CIGTA I L
RELAY 7.5A DOME 40A DOOR LOCK CB
2 1
1 2
4 8
2 3
3 4
G
W±R
P±L B±Y
B±Y
W±R
AM2 IG2
ACC
IG1AM1W W
W±R
W W
W±B
21
1
1
1
1
2
2
2
2
3
4
3
4 1
2
1
22
1
11
1
IGNITION SW I 8
Battery
30A AM2
2
Starter S 220A RADIO NO.1
10A HORN
15A EFI
7.5A DOMEShort Pin
10A HAZARD
The chart below shows the route by which current flows from the battery to each electrical source
(Fusible Link, Circuit Breaker, Fuse, etc.) and other parts.
Engine Room R/B (See Page 20)
ABS
ABS and Traction Control
Cruise Control
Electronically Controlled Transmission and A/T Indicator
Multiplex Communication System
Cigarette Lighter and Clock
Key Reminder and Seat Belt Warning STOP
Fuse Page
194
214
11 2
System
DOME 20A
10ACombination Meter
Headlight
Interior Light
2
2
6 100A ALT
EB1
POWER SOURCE
Light Auto Turn Off187
180
166
210
230
122
10A ECU±B
5 60A ABS
2
6 Fusible Link Block2
*The system shown here is an EXAMPLE ONLY. It is different to the actual circuit shown in the SYSTEM CIRCUITS SECTION.

2001 PRIUS (EWD414U)
ENGINE CONTROL
This system utilizes an engine control module and maintains overall control of the engine, transmission and so on. An outline
of the engine control is explained here.
1. INPUT SIGNALS
(1) Engine coolant temp. signal circuit
The engine coolant temp. sensor detects the engine coolant temp. and has a built±in thermistor with a resistance which
varies according to the engine coolant temp. thus the engine coolant temp. is input in the form of a control signal into
TERMINAL THW of the engine control module.
(2) Intake air temp. signal circuit
The intake air temp. sensor is installed in the mass air flow meter and detects the intake air temp., which is input as a
control signal into TERMINAL THA of the engine control module.
(3) Oxygen sensor signal circuit
The oxygen density in the exhaust gases is detected and input as a control signal into TERMINALS OX1A and OX1B of
the engine control module.
(4) RPM signal circuit
Camshaft position and crankshaft position are detected by the camshaft position sensor and crankshaft position sensor.
Camshaft position is input as a control signal to TERMINAL G2 of the engine control module, and engine RPM is input
into TERMINAL NE+.
(5) Throttle signal circuit
The throttle position sensor detects the throttle valve opening angle, which is input as a control signal into TERMINALS
VTA and VTA2 of the engine control module.
(6) Vehicle speed signal circuit
The vehicle speed signal from brake ECU, detects the vehicle speed and inputs a control signal into TERMINAL SPD of
the engine control module via the combination meter.
(7) Battery signal circuit
Voltage is constantly applied to TERMINAL BATT of the engine control module. When the ignition SW is turned on, the
voltage for engine control module start±up power supply is applied to TERMINAL +B of the engine control module via
EFI relay.
(8) Engine knock signal circuit
Engine knocking is detected by knock sensor and the signal is input into TERMINAL KNK1 of the engine control module
as a control signal.
2. CONTROL SYSTEM
*SFI system
The SFI system monitors the engine condition through the signals, which are input from each sensor to the engine
control module. The best fuel injection volume is decided based on this data and the program memorized by the engine
control module, and the control signal is output to TERMINALS #10, #20, #30 and #40 of the engine control module to
operate the injector. (Inject the fuel). The SFI system produces control of fuel injection operation by the engine control
module in response to the driving conditions.
*ESA system
The ESA system monitors the engine condition through the signals, which are input to the engine control module from
each sensor. The best ignition timing is detected according to this data and the memorized data in the engine control
module, and the control signal is output to TERMINALS IGT1, IGT2, IGT3 and IGT4. This signal controls the ignition coil
and igniter to provide the best ignition timing for the driving conditions.
*Fuel pump control system
The engine control module operation outputs to TERMINAL FC and controls the CIR OPN relay. Thus controls the fuel
pump drive speed in response to conditions.
3. DIAGNOSIS SYSTEM
With the diagnosis system, when there is a malfunctioning in the engine control module signal system, the malfunction
system is recorded in the memory. The malfunctioning system can then be found by reading the display (Code) of the
malfunction indicator lamp.
4. FAIL±SAFE SYSTEM
When a malfunction occurs in any system, if there is a possibility of engine trouble being caused by continued control based
on the signals from that system, the fail±safe system either controls the system by using data (Standard values) recorded in
the engine control module memory or else stops the engine.
SYSTEM OUTLINE

NEW MODEL OUTLINE
MAIN MECHANISM
12
Low-emission & high-fuel efficiency.
TOYOTA hybrid system leading the way into the next
generation.
Tackling the challenge for high fuel efficiency and
low emissions
Prius - the mass-production gasoline hybrid vehicle - already meets all of the various strict emission levels
being proposed throughout the world, well ahead of the competition. What's more, through the use of the
hybrid system, surpassing fuel efficiency and a massive reduction in CO
2 has become a reality. The Prius
can truly be acclaimed as ªthe clean and environmentally friendly vehicle.º
Emission Reduction Features
1. Precision Emission Control
Through full utilization of the two Oxygen sensors, precision emission control is made possible even when
the engine is frequently stopped and re±started. Furthermore, excellent purification of exhaust gas is ensured
through the catalytic converter, resulting in reduced emissions.
2. Vapor Reducing Fuel Tank System
We have developed a new fuel tank system that can dramatically reduce the amount of fuel vapor generated
in the tank both when the vehicle is moving as well as when it is at a standstill. This system is the first one
in the world to be used.
3. TOYOTA HC Adsorber and Catalyst System
A new system has been adopted which adsorbs the HC that is emmitted between the time the engine is cold-
started and the catalytic converter is still cool and not yet activated, until the time the catalytic converter be-
comes active.
After the catalytic converter has been activated, the HC disassociates little by little and is then purified.
4. Adoption of a Thin-walled High-density Cell Catalytic Converter
In order to reduce the amount of time taken until the catalytic converter is activated, we developed a catalytic
chamber with a super thin ceramic wall. Also, high-density cells have been utilized as a measure to improve
strength and increase contact area with exhaust gas. Through these measures we have been able to achieve
a balance of reliability and purification efficiency.

NEW MODEL OUTLINE
Gasoline engine + AC motor = TOYOTA Hybrid System (THS)
Tremendous improvement in fuel efficiency & clean achieved!
Inverter1NZ-FXE
engine
P111 Hybrid transaxleHV battery182MO11182MO12
Hybrid transaxle
13
TOYOTA Hybrid System (THS)
The TOYOTA hybrid system has two drive sources, one is the gasoline engine and the other, the AC motor.
The power train system selects the best combination of the different characteristics of both depending on
driving conditions. Also, through the adoption of a regenerative braking system, which recovers energy
during deceleration and ªidling stopº whereby the engine is stopped during idling, we have been able to
provide for maximum energy conservation. This has resulted in a vastly superior fuel economy compared
with that of gasoline A/T vehicles of the same displacement.
Features of the System
1. Optimum distribution of drive sources
The most efficient engine operating zone is automatically selected by controlling the optimum distribution of the engine and motor
drive energy sources.
2. Reduced energy loss
The engine is automatically stopped when starting and travelling at low load to reduce fuel consumption.*1
The kinetic energy that used to be lost through engine or foot braking is recovered by the regenerative braking system and used
for recharging, thereby contributing to improved fuel efficiency. When the driver applies the brakes, the hydraulic and regenera-
tive braking systems are coordinated. In order to recover more energy, a higher proportion of regenerative braking is used.
3. Not required for recharging from an external source
The system uses MG1 (Motor Generator No.1) and MG2 (Motor Generator No.2) to maintain a constant battery charge, so unlike
an electric vehicle, recharging from an external source is not required.
*1 : In some cases, the engine does not stop, depending on the air conditioner and HV battery (Hybrid Vehicle Battery) status.
System configuration
P111 HYBRID TRANSAXLE
Fitted with built-in THS transaxle MG1 (Motor Generator No.1), MG2 (Motor Generator No.2), power spliting device and reduction
gears for the hybrid system. These function to switch engine operation to MG2 assistance, HV battery charging and power generation
for driving MG2.
Inverter
This controls the current between MG1, MG2 and HV battery and converts DC/AC power.
HV Battery (Hybrid Vehicle Battery)
This supplies power to the motor at full load or on engine stopping and stores power recovered by regenerative braking or power
generation by MG1. 228 nickel-metal hydride batteries are connected in series to obtain a voltage of 273.6 V DC.

NEW MODEL OUTLINE
MAIN MECHANISM
182MO13
182MO14
182MO15
182MO16
182MO17
14
THS operation
Starting and traveling at low load
When the engine efficiency is low such as when starting,
traveling at low load or the engine is stopped, permitting
travel by MG2; (however the engine may start under
SOC (State Of Charge) of the HV battery.)
Normal traveling
The engine energy is divided into two. One portion
directly drives the wheels. The other portion drives
MG1 to drive MG2 by generated power, which also
drives the wheels.
Full acceleration
In addition to the 2-way system for normal travelling,
the drive power of MG2 is further supplemented by the
power stored in the HV battery, resulting in powerful
and smooth acceleration.
Deceleration or braking
The wheels drive MG2 which acts as the generator for
regenerative power generation. The power recovered
by generation is stored in the HV battery.
Stopped
When the vehicle is stopped, the engine stops automat-
ically. However, when it is necessary to charge the HV
battery or to run the air conditioner compressor, the
engine will not stop.

NEW MODEL OUTLINE
MAIN MECHANISM
182CH29
16
4 Features of the 1NZ-FXE engine
1. Highly efficient and high expansion ratio gasoline engine
Adoption of a super fuel-efficient engine developed for use with THS. Its high expansion ratio cycle is achieved by applying the
Atkinson cycle*1 which obtains high thermal efficiency.
2. Reduction in frictional loss
The maximum engine speed is set at 4,500 rpm to reduce frictional resistance, thereby producing a highly efficient low-speed
engine.

An offset crankshaft with 12 mm deviation from the center axis of the cylinder bore is utilized to reduce frictional resistance
of the piston.

Frictional resistance is reduced through the use of low tension valve springs and piston rings.

Lightweight design has been adopted for reciprocating engine parts.
The above measures for reducing frictional loss contribute to improved fuel economy.
3. VVT-i (Variable Valve Timing -intelligent)
The timing of the opening and closing of the intake valves is controlled by the computer according to driving conditions, such
as engine speed and level of acceleration. Thus, smooth intake and exhaust are achieved to greatly improve torque in the low
and medium speed zones. This also contributes to better fuel economy and purification of exhaust gas. Then the VVT-i function
is used to reduce vibration when the engine starts.
4. Compact, lightweight, and low emission
Adoption of an aluminum cylinder block and compact design of parts. And, by positioning the catalytic converter near the engine
for a backwards exhaust layout, we have been able to reduce emissions when the engine is cold started.
*1 : Atkinson Cycle: Proposed by an English engineer named James Atkinson, this thermal cycle enables the compression stroke
and the expansion stroke of the mechanism to be set independently of each other.
Suspension
MacPherson strut type suspension with L-shape
lower arms has been adopted in the front and
torsion beam with toe control link suspension
in the rear. Also, each component part is opti-
mally located and tuned for both excellent con-
trollability and enhanced riding comfort.
EMPS (Electric Motor-assisted Power Steering)
System
Vehicle speed sensing type electric motor-assisted power steering is fitted as standard. Unlike conventional
hydraulic power steering, EMPS does not depend on an engine for its power source, providing a steering feel
in no way inferior to conventional steering when the engine has stopped. Thus it is suitable for the HV system.
Other merits include improved fuel economy through energy conservation, lighter weight, and no need to fill
the power steering fluid.

ENGINE ± 1NZ-FXE ENGINE
182EG12
A ± A Cross Section Throttle Control Motor
AA
Throttle Position SensorReturn Spring
Opener Spring
182EG13
Vacuum Port55
INTAKE AND EXHAUST SYSTEM
1. Throttle Body

The adoption of the ETCS-i has realized excellent throttle control.

The ISC system and cruise control system are controlled comprehensively by the ETCS-i.

The ETCS-i, which drives the throttle valve through a DC motor that is controlled by the ECM, thus doing
away with a throttle link to connect the accelerator pedal to the throttle valve, has been adopted.

The throttle control motor is provided with a return spring that closes the throttle valve.

An opener spring is provided on the throttle position sensor side. This spring opens the throttle valve slight-
ly when the engine is stopped to prevent the throttle valve from sticking and to improve the engine's restart-
ability.

A warm coolant passage is provided below the throttle body to prevent the throttle valve from freezing
during cold temperatures.
2. Intake Manifold

Because it is not necessary to improve the in-
take air efficiency through inertial intake due to
the adoption of the Atkinson cycle, the length
of the intake pipe of the intake manifold has
been shortened, and furthermore, the intake
pipes for cylinders #1 and #2, as well as for #3
and #4, have been integrated midstream to
achieve a large-scale weight reduction.
In addition, the throttle body has been oriented
downflow in the center of the surge tank to
achieve a uniform intake air distribution.

A vacuum port has been provided for the Toyo-
ta HC adsorber and catalyst system.

ENGINE ± 1NZ-FXE ENGINE62
ENGINE CONTROL SYSTEM
1. General
The engine control system for the 1NZ-FXE engine has following system.
System
Outline
SFI
Sequential Multiport
Fuel InjectionAn L-type SFI system directly detects the intake air volume with a hot-wire
type mass air flow meter.
ESA
Electronic Spark
AdvanceIgnition timing is determined by the ECM based on signals from various
sensors. The ECM corrects ignition timing in response to engine knocking.
VVT-i
Variable Valve
Timing-intelligentControls the intake camshaft to an optimal valve timing in accordance with
the engine condition.
ETCS-i
Electronic
Throttle Control
System-intelligentOptimally controls the throttle valve opening in accordance with the ECM,
and the conditions of the engine and the vehicle, and comprehensively
controls the ISC and cruise control system.
Fuel Pump Control
Fuel pump operation is controlled by signal from the ECM.

To stop the fuel pump during operation of the SRS airbag.
Oxygen Sensor Heater
ControlMaintains the temperature of the oxygen sensors at an appropriate level to
increase accuracy of detection of the oxygen concentration in the exhaust gas.
Evaporative Emission
Control

The ECM controls the purge flow of evaporative emissions (HC) in the
charcoal canister in accordance with engine conditions.

Using 3 VSVs and a vapor pressure sensor, the ECM detects any
evaporative emission leakage occurring between the fuel tank and the
charcoal canister, and vapor reducing fuel tank through the changes in the
tank pressure. For details, see page 79.
Toyota HCAC System
The ECM controls the VSV (for Toyota HCAC System) to improve the clean
emission performance of the exhaust gas when the temperature of the TWC
is low. For details, see page 58.
Air Conditioning
Cut-Off ControlBy turning the air conditioning compressor OFF in accordance with the
engine condition, drivability is maintained.
Cooling Fan ControlRadiator cooling fan operation is controlled by signals from ECM based on
the engine coolant temperature sensor signal (THW).
HV Immobiliser
Prohibits fuel delivery, ignition, and starting the HV system if an attempt is
made to start the HV system with an invalid ignition key. For details, see page
80.
DiagnosisWhen the ECM detects a malfunction, the ECM diagnoses and memorizes
the failed section.
Fail-SafeWhen the ECM detects a malfunction, the ECM stops or controls the engine
according to the data already stored in memory.