2001 TOYOTA PRIUS ESP

2001 PRIUS (EWD414U)
B HOW TO USE THIS MANUAL
The ground points circuit diagram shows the connections from all major parts to the respective ground points. When
troubleshooting a faulty ground point, checking the system circuits which use a common ground may help you identify
the problem ground quickly. The relationship between ground points (
EA, IB and IC shown below) can also be
checked this way.

I GROUND POINT
FAN MAIN RELAY
FAN MAIN RELAY
A/C FAN RELAY NO.2
A/C FAN RELAY NO.3
RADIATOR FAN MOTOR
RETRACT CONTROL
RELAY
RETRACT MOTOR RH
RETRACT MOTOR LH
FRONT TURN SIGNAL
LIGHT RH
PARKING LIGHT RH
FRONT TURN SIGNAL
LIGHT LH
PARKING LIGHT LH
DOOR LOCK CONTROL
SW RH
DOOR KEY LOCK
SW RH
DOOR LOCK MOTOR
RH
BLOWER RESISTOR
A/C AMPLIFIER
RADIO AND PLAYER
HEATER RELAY
AUTO ANTENNA
MOTOR
BLOWER SW
PARKING BRAKE SW
COMBINATION METER
HORN SW [COMB. SW]
TURN SIGNAL FLASHER
DOOR KEY LOCK SW LH
DOOR LOCK MOTOR LH
FUEL CONTROL SW
WOOFER AMPLIFIER
COMBINATION METER
COMBINATION METER
FUEL SENDER
CIGARETTE LIGHTER
O/D MAIN SW
CLOCK
5
5
5
5
4
4
4
4
4BA15
IB18
EA2 10
3E5
3E
6 3G
13 3F
3 3D
1 3B
7
ID115
IC33
IA12
E 3
A
A AW±B
W±BW±B W±B
W±B W±B
W±B
W±B
W±B
W±B
W±B
W±B
W±B
W±B
W±B W±BW±B W±B W±B W±B
W±B W±B
W±BW±B
W±B
W±B
W±B W±B
W±B
BR
W±B
BR BRW±BW±B
W±B
W±B
W±B
W±B
W±B
W±B
W±B
W±B
W±B W±B
W±B
W±B
W±B
W±B
BR W±B
BR BR
BR W±B W±BW±B
W±BW±BBR W±B (4A±GZE)
W±B A A A
I 6
I 6
I 2
I 2
I 2
B 5I 5
I 5
I 5
B 5
B 5
B 5
I 5
I 5
I 3I 3
E 3
E 3
E 3
E 2
E 4
E 5
E 4
E 5
E 6E 4
E 4
B 4
EAI 4
B 4
B 4
I 4I 8
IBIC
3C7
4
JUNCTION
CONNECTOR J 1
4
DOOR LOCK CONTROL
RELAY
ELECTRICAL IDLE-UP
CUT RELAY (M/T)FRONT SIDE MARKER
LIGHT RH
FRONT SIDE MARKER
LIGHT LH
BRAKE FLUID LEVEL
WARNING SW
UNLOCK WARNING
SW WIPER AND WASHER
SW [COMB. SW] LIGHT CONTROL SW
[COMB. SW] HEATER CONTROL
ASSEMBLY
HEATER SERVO
MOTOR AMPLIFIER
DIMMER SW
[COMB. SW]
CRUISE CONTROL
MIRROR SW
REAR WINDOW
DEFOGGER SW
POWER WINDOW
MASTER SW
POWER WINDOW
CONTROL RELAY
DOOR LOCK CONTROL
SW
REMOTE CONTROL
MIRROR SW
*The system shown here is an EXAMPLE ONLY. It is different to the actual circuit shown in the SYSTEM CIRCUITS SECTION.

2001 PRIUS (EWD414U)
E GLOSSARY OF TERMS AND SYMBOLS
BATTERY
Stores chemical energy and
converts it into electrical energy.
Provides DC current for the auto's
various electrical circuits.GROUND
The point at which wiring attaches to
the Body, thereby providing a return
path for an electrical circuit; without a
ground, current cannot flow.
CAPACITOR (Condenser)
A small holding unit for temporary
storage of electrical voltage.HEADLIGHTS
Current flow causes a headlight
filament to heat up and emit light. A
headlight may have either a single
(1) filament or a double (2) filament
1. SINGLE
FILAMENT
CIGARETTE LIGHTER
An electric resistance heating
element.2. DOUBLE
FILAMENT
CIRCUIT BREAKER
Basically a reusable fuse, a circuit
breaker will heat and open if too
much current flows through it.
Some units automatically reset when
cool, others must be manually reset.HORN
An electric device which sounds a
loud audible signal.
DIODE
A semiconductor which allows
current flow in only one direction.IGNITION COIL
Converts low±voltage DC current
into high±voltage ignition current for
firing the spark plugs.
DIODE, ZENERA diode which allows current flow in one
direction but blocks reverse flow only up
to a specific voltage. Above that potential,
it passes the excess voltage. This acts as
a simple voltage regulator.LIGHT
Current flow through a filament
causes the filament to heat up and
emit light.
PHOTODIODE
The photodiode is a semiconductor
which controls the current flow
according to the amount of light.LED (LIGHT EMITTING DIODE)
Upon current flow, these diodes emit
light without producing the heat of a
comparable light.
DISTRIBUTOR, IIA
Channels high±voltage current from
the ignition coil to the individual
spark plugs.METER, ANALOG
Current flow activates a magnetic
coil which causes a needle to move,
thereby providing a relative display
against a background calibration.
FUSEA thin metal strip which burns through
when too much current flows through it,
thereby stopping current flow and
protecting a circuit from damage.
FUSIBLE LINK
METER, DIGITAL
Current flow activates one or many
LED's, LCD's, or fluorescent
displays, which provide a relative or
digital display.
FUEL
FUSIBLE LINK
A heavy±gauge wire placed in high
amperage circuits which burns through on
overloads, thereby protecting the circuit.
The numbers indicate the crosssection
surface area of the wires.(for Medium Current Fuse)
(for High Current Fuse or
Fusible Link)MOTOR
A power unit which converts
electrical energy into mechanical
energy, especially rotary motion.
M

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 EQUIPMENT
182MO23(For U.S.A.)
Glove box Accesory box Multi-box
Front door pocket
Seat back pocket
(Driver's and
passenger seat)
182MO24182MO09
182MO25
Small storage box
Cup holder
(for two caps use)11.839ft3 (by SAE suitcase method)
luggage space is secured.182MO26182MO27182MO28
18
Air Conditioning
An automatic air conditioning has been adopted
in consideration to ease of use.

A clean air filter which removes pollen and
dust is included as a standard fitting for puri-
fying the air inside the cab.

Two air conditioning modes, A/C for eco-
nomical air conditioning and MAX for espe-
cially strong air conditioning, are provided.
Wireless Door Lock Remote Control System
With the wireless door lock remote control system, all the doors can be locked and unlocked by signals emitted
by the transmitter.
Power Window System
A power window system which enables all windows to be raised or lowered with switches has been adopted.
An auto up/down function and jam protection function have been added to the driver's power window.
HV Immobiliser System
HV immobiliser system will not allow the HV system to be started by duplicate key is used. This system
will permit the HV system to be started only when the ID code of the transponder chip impregnated in the
key matches the ID code registered beforehand in the transponder key amplifier.
Theft Deterrent System
When an attempt is made to forcibly enter the vehicle or open the hood or trunk lid without a key, or when
the battery terminals are removed and reconnected, this system sounds the horn and flashes the headlights,
taillights and emergency flashers for about 1 minute to alert the owner. At the same time, it locks all the
doors.
Storage Space
Ample storage space with an emphasis on practicality provided throughout the Prius.
Instrument panel (passenger seat)Seat back pocketFront door pocket
Center console boxLuggage space

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.

ENGINE ± 1NZ-FXE ENGINE
182EG40
Vane (Fixed on Intake Camshaft)
Intake
Camshaft
Housing
165EG34
To VVT-i Controller
(Advanced Side) (Retard Side)
SleeveSpool Valve
Spring
Drain
Oil
PressureDrain
CoilPlunger 68
Construction
1) VVT-i Controller
This controller consists of the housing driven from the timing chain and the vane coupled with the intake
camshaft.
The oil pressure sent from the advance or retard side path at the intake camshaft causes rotation in the
VVT-i controller vane circumferential direction to vary the intake valve timing continuously.
2) Camshaft Timing Oil Control Valve
The camshaft timing oil control valve controls
the spool valve position in accordance with
the duty control from the ECM thus allocating
the hydraulic pressure that is applied to the
VVT-i controller to the advance and the retard
side. When the engine is stopped, the cam-
shaft timing oil control valve is in the most re-
tarded state.

ENGINE ± 1NZ-FXE ENGINE
182EG31
Accelerator Pedal
Position SensorThrottle Valve
Throttle Position Sensor
Throttle Control
Motor
HV
ECUECM
182EG33 182EG32
Accelerator Pedal
Position Sensor(V)
5.0
4.0
3.0
2.0
1.0
0 10 2030 405060 70 80
125Output Voltage
Accelerator Pedal Depressed AngleVPA2
VPA1 74
8. ETCS-i (Electronic Throttle Control System-intelligent)
General
The ETCS-i, which realizes excellent throttle control in all the operating ranges, has been adopted.
In the conventional throttle body, the throttle valve opening is determined invariably by the amount of
the accelerator pedal effort. In contrast, the ETCS-i used the ECM to calculate the optimal throttle valve
opening that is appropriate for the respective driving condition and uses a throttle control motor to control
the opening.
The ETCS-i controls the ISC (Idle Speed Control) system and the cruise control system.

System Diagram 
Construction
1) Accelerator Pedal Position Sensor
The accelerator pedal position sensor is mounted on the accelerator pedal. To detect the pedal opening
angle, 2 separate systems consisting of main and sub sensors are used, and 2 separate return springs are
used to improve reliability. In the detecting portions, Hall elements have been adopted. Due to the charac-
teristics of the Hall elements, different signals are output depending on whether the pedal is pressed all
the way or is released. To correct these signals, a mechanical device has been provided to detect the cor-
rect pedal opening angle. The sensors of the 2 systems output the same signals.

ENGINE ± 1NZ-FXE ENGINE
150EG39150EG40
Close
Open
VC VTA1 VTA2 E2V
5
0 Close
Output Voltage
Open VTA1 VTA2
Accelerator Pedal Depressed Angle75
2) Throttle Position Sensor
The throttle position sensor is mounted on the throttle body.
The throttle position sensor converts the amount of accelerator pedal effort into two types of electrical
signals with distinct output characteristics. The signals are then input into the ECM.
3) Throttle Control Motor
A DC motor with excellent response and minimal power consumption is used for the throttle control mo-
tor. The ECM performs the duty ratio control of the direction and the amperage of the current that flows
to the throttle control motor in order to regulate the opening angle of the throttle valve.
Operation
The ECM drives the throttle control motor by determining the target throttle valve opening in accordance
with the respective operating condition.
1) Idle Speed Control
The idle speed control is effected entirely by the ETCS-i. The following are the contents of the control:
idle-up control during cold engine operation, intake air volume control to improve the startability of the
engine, and control for when the electrical load changes such as when the air conditioning switch is turned
ON or OFF.
2) Cruise Control
Through the adoption of the ETCS-i, the vehicle speed is now controlled by the throttle control motor,
which controls the throttle valve.