2001 TOYOTA PRIUS light

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
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 ENGINE
182EG25
Engine Load
Full Load Performance
Range 4Range 5
Range 3
Range 2
Range 1Engine Speed
TDC
EXIN
BDCLatest
timing
To retard
side
IN
EX
To advance
side
EX IN71
In proportion to the engine speed, intake air volume, throttle position and water temperature, the ECM cal-
culates an optimal valve timing under each driving condition and control the camshaft timing oil control
valve. In addition, ECM uses signal from the camshaft position sensor and the crankshaft position sensor
to detect the actual valve timing, thus performing feedback control to achieve the target valve timing.

Operation During Various Driving Condition (Conceptual Diagram) 
Operation StateRangeValve TimingObjectiveEffect
During Idling1
182EG26
Eliminating overlap to
reduce blow back to the
intake sideStabilized
idling rpm
Better fuel
economy
At Light Load2
182EG27
Decreasing overlap to
eliminate blow back to
the intake sideEnsured
engine
stability
At Medium
load3
182EG28
Increasing overlap to
increase internal EGR for
pumping loss elimination
Better fuel
economy
Improved
emission
control

ENGINE ± 1NZ-FXE ENGINE 76
Fail Safe
If an abnormal condition occurs with the ETCS-i, the check engine warning light in the combination meter
illuminates to alert the driver. The current to the throttle control motor is cut off to prevent the ETCS-i from
operating. This enables the return spring to close the throttle valve.
Diagnosis
If the diagnostic trouble code 89 is being output to the combination meter check engine warning light, it
means that the ECM has detected a malfunction in the ETCS-i, and outputs the diagnostic trouble code of
the ETCS-i.
Also, the diagnostic trouble code can be output to a hand-held tester via the data link connector 3.
For details, refer to the 2001 Prius Repair Manual (Pub. No.RM778U).

THS (TOYOTA HYBRID SYSTEM)
182TH24
ªREADYº LightOutput Control
Warning Light 26
DRIVING CHARACTERISTICS
Because the Prius uses a parallel series hybrid system, some aspects of its operation may differ from those of
existing automobiles, and may require precautions that are unique to this system.
1. Starting the THS
Make sure that the parking brake is engaged and that the shift lever is in the P position.
While depressing the brake pedal, turn the ignition switch to the START position. After this, the ªREADYº
light flashes.
The engine does not start when the shift lever is in the N position; it can only start in the P position. When
the external air temperature is low, the ªREADYº light may flash longer than usual.
As soon as the engine has started, the ªREADYº light illuminates steadily and a beeping sound is heard.
Several seconds after the engine warms up, the engine stops automatically, provided that the air conditioning
compressor does not need to operate and that the HV battery maintains a proper SOC (state of charge).
2. Start-Off
While keeping the brake pedal depressed, release
the parking brake, and move the shift lever to the
D position.
The vehicle has the same creeping movement as
the conventional automatic transmission vehicles.
Gradually release the brake pedal and slowly de-
press the accelerator pedal to start off.
At this time, the vehicle starts off powered only by
the MG2 (Motor Generator No.2)
NOTICE: The vehicle can be started off, provided that the ªREADYº light remains illuminated, even
if the engine remains stopped.
3. Acceleration
Depress the accelerator pedal to accelerate the vehicle.
If the engine remained stopped during start-off, the engine will start automatically during acceleration.
4. Downhill Driving
Move the shift lever to the B position as necessary in order to simultaneously apply the regenerative brake
and the engine friction brake.
5. Deceleration and Stopping
Depress the brake pedal to decelerate and to stop the vehicle.
Depressing the brake pedal causes the regenerative brake to activate automatically in the D or B position. (In
the regenerative brake system, kinetic energy is converted to electrical energy.) If the engine has warmed up,
the air conditioning compressor does not need to operate, and if the HV battery maintains a proper SOC (state
of charge), the engine stops automatically when the vehicle speed drops-even if the vehicle comes to a stop.
6. Parking
Push down the parking brake pedal, move the shift lever to the P position, and pull out the ignition key.
NOTICE: Make sure to pull out the ignition key after parking the vehicle because the vehicle can be
driven as long as the ªREADYº light remains illuminated even if the engine is stopped.
7. Other Characteristics and Precautions

If a drive wheel slips on slippery terrain, causing the front wheels to spin faster than the rear wheels, the
THS effects control to limit the slippage by restraining the drive force. (This also protects the planetary
gear from damage.)

When the HV battery temperature is too high or low, the output control warning light illuminates, alerting
the driver that output power may be limited.
This is not 2 malfunction. This condition may be corrected by avoiding sudden acceleration /decelaration,
after which the light will go out.

When the vehicle is stopped and the shift lever is in the N position, electricity is not generated even if the
engine is running. If the vehicle remains stopped for a long time, make sure to move the shift lever to the
P position. In heavy traffic, keep the shift lever in the D position.

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)
182TH33
31
± REFERENCE ±
The MG1 and the MG2 are generally shut down when the shift lever is in the N position.
However, the shut-down function is canceled under the following exceptions:

During driving, if the brake pedal is depressed and a wheel locks up, the ABS is activated. After this, low
torque is requested from the MG2 to provide supplemental power in order to restart the rotation of the wheel.
Even if the shift lever is in the N position at this time, the shut-down function is canceled to allow the wheel
to rotate. After the wheel rotation has been restarted, the system resumes its shut-down function.

When the vehicle is driven in the D or B position and the brake pedal is depressed, the regenerative brake
operates. At this time, as the driver moves the shift lever to the N position, the brake hydraulic pressure in-
creases while the request torque of the regenerative brake decreases gradually so as not to create a sluggish
brake feel. After this, the system effects its shut-down function.
When any of the conditions described below is pres-
ent, the message prompt as shown appears in the
multi information display, accompanied by the illu-
mination of the master warning light and the continu-
ous sounding of the buzzer.

The ªREADYº light is illuminated, the shift lever
is in the N position, and the HV battery is dis-
charged.

The ªREADYº light is illuminated, the shift lever
is in the N position, and the driver's door is open.

The ªREADYº light is illuminated, the parking brake is engaged, the shift lever is in the B or D position, and
the driver's door is open.