radiator TOYOTA PRIUS 2001 Service User Guide

2001 PRIUS (EWD414U)
M
1
234
22 PRIUS
Power Source
1120A MAIN
100A DC/DC
IE Cowl side
panel LHA 1D 1B
B± G
J 1
JUNCTI ON
CONNE CTOR F18
FUSI BL E LI NK
BL OCK NO. 2
BATTERYF1 1 F13,
FUSI BL E LI NK
BL OCK NO. 1BDRadiator Fan and Condenser Fan
5
3 1
2
5A AM1
2B 3 2D 6
2K 8
B±Y W±GIG1 RELAY
12H 2G7
B5A E CU± I G
40A DEF
W
24
2M 4
32
51
ID Cowl side
panel LHA
J11
JUNCTI ON
CONNE CTOR30A
RDI
2 1
3 5
5 3
2 1
4
2 1
3 5
1J 5 1K 71J10 1A 11 1K 31K 21K51J12
1 2
M6IE1
7IE1
2 1
M
3 21J 4
EA
AB
11 IE1
1 2 W±B
W±B
W± B
To Engine Contr ol
Module< 2±13>A 3
A/ C SI NGLE
PRESSURE SW
W 4
WATER TEMP. SW To A/C Amplifier
< 24±7>
N 4
NOI S E FI LTE R
(
Rear Window Def ogger)J 7
JUNCTI ON
CONNECTOR
JUNCTION
CONNECTORB A J27 J28,
A 1
A/ C CONDENS ER FAN
MOTOR
DEF
RELAYFAN NO. 2
REL AYFA N NO. 3
RELAY
AA 13
AA
V±Y V±Y V±Y V±Y
W±B
W±B W±B
L±W W± BLGL±W R± W
W± G G± W
B±Y
W
WB
1 I15
IGNITION SW15 A
W±G
2
11GR ±R GR3 MPX± MPX+
FAN NO. 1
RELA Y
GR±R
W±B W±B R 1
RADI A TOR FA N
MOTO R 30A
CDS FAN
Rear W indow Defogger
1B 3
ACC
IG1
ST1 AM1
DFG
BODY ECUA B 8
10A GAUGE
REA R WI N DOW DEFOGGE R R± W
W
2 11
2
C1 1
COMB I NATI ON
METEREA
V± Y
To A/C Amplifier
< 24±6>
MPX+
PSG
SW
RDEF
REAR WI NDOW
DEFOGGER SW A 7
A/ C AMPL I FI ER
MPX +B±Y

ENGINE ± 1NZ-FXE ENGINE
182EG10
171EG17
From Heater
To Heater
To Radiator
From Radiator
Water Pump
Cylinder Head
Heater Core
Throttle Body
Radiator Cylinder Block Bypass
Passage
Water Pump
Thermostat53
COOLING SYSTEM
1. General

The cooling system is a pressurized, forced-circulation type.

A thermostat with a bypass valve is located on the water inlet housing to maintain suitable temperature
distribution in the cooling system.

The flow of the engine coolant makes a U-turn in the cylinder block to ensure a smooth flow of the engine
coolant.

The radiator for the engine and the A / C condenser have been integrated to minimize the space they occupy
in the engine compartment.

ENGINE ± 1NZ-FXE ENGINE
182EG11
Radiator
Condensor
RadiatorCondensor
Cutout 54
2. Radiator
The radiator for the engine and the A / C condenser have been integrated to minimize the space they occupy
in the engine compartment. Cutouts have been provided between the radiator and condenser sections to pre-
vent the transfer of heat between the two sections.

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.

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.

BODY ELECTRICAL ± AIR CONDITIONING 152
AIR CONDITIONING
DESCRIPTION
The air conditioning system in the Prius has the following features:
Both heating and demisting performances are realized by adopting performances are realized by adopting
the 2-way flow heater type air conditioning unit.
A multi-tank, super-slim structure evaporator has been adopted.
An automatic air conditioning system which provides enhanced air conditioning comfort according to the
occupant's senses has been adopted.
A semi-center location air conditioning unit, in which the evaporator and heater core are placed in the ve-
hicle's longitudinal direction, has been adopted.
A compact, high-performance scroll compressor with oil separator has been adopted.
The heat exchange efficiency has been improved through the adoption of the sub-cool condenser.
This condenser is integrated with the radiator to minimize the space they occupy in the engine compart-
ment.
A compact, lightweight, and highly efficient straight flow (full-path flow) aluminium heater core has been
adopted.
This heater core is integrated with a PTC (Positive Temperature Coefficient) heater, which excels in heat-
ing performance.
PTC heaters have been provided in the air duct at the footwell outlet in front of the air conditioning unit.
However, air conditioning without the PTC heaters is offered as an option on the U.S.A. models.
An electrical water pump with a bypass valve that provides a stable heater performance even if the engine
is stopped due to a function of the THS (TOYOTA Hybrid System) has been adopted.
A clean air filter that excels in removing pollen and dust is standard equipment.

BODY ELECTRICAL ± AIR CONDITIONING
Ventilation and
Heater Air Conditioning
153

Performance 
ItemPerformance
Heat Output W5300
HeaterAir Flow Volume m3/h330
Power Consumption W170
Heater Core Inte-
grated PTC HeaterHeat Output W330 (165 x 2)
PIC Heater*1Heat Output W165 x 2
Heat Output W4200*2
Air ConditioningAir Flow Volume m3/h450g
Power Consumption W200
*1: U.S.A. Cold Area Specification Model and Canada Model
*
2: When the compressor is at 1,800 rpm

Specifications 
ItemSpecifications
TypeStraight Flow
(Full-path Flow)
Heater CoreSize
W x H x L mm (in.)216.9 x 140 x 27
(8.5 x 5.5 x 1.1)
Fin Pitch mm (in.)1.8 (0.07)
Motor TypeS70F-13T
BlowerFan SizeExternal Air132 x 41
(5.2 x 1.6)
Fan Size
Dia. x H mm (in.)Internal Air150 x 36
(5.9 x 1.4)
TypeMulti-Flow Type
(Sub-Cool Type)
CondenserSize
W x H x L mm (in.)600 x 349.8 x 37.5*
(23.6 x 13.8 x 1.5)
Fin Pitch mm (in.)2.8 (0.11)
TypeDrawn Cup
(Multi-tank, Super Slim Structure)
EvaporatorSize
W x H x L mm (in.)253.2 x 215 x 58
(10.0 x 8.5 x 2.3)
Fin Pitch mm (in.)3.5 (0.14)
CompressorTypeSCS06
*: With the radiator

BODY ELECTRICAL ± AIR CONDITIONING
163BE17
Inner FinAntibacterial Agent
Nylon Layer
Chromate Layer
Aluminum
Matrix
182BE48
ModulatorMulti-Flow Condenser
Condensing Portion
Gaseous Refrigerant
Liquid Refrigerant
Super-Cooling Portion 158
Evaporator
By placing the tanks at the top and the bottom of the evaporator unit and by adopting an inner fin construc-
tion, the heat exchanging efficiency has been improved and the evaporator unit's temperature distribution
has been made more uniform. As a result, it has become possible to realize a thinner evaporator construction.
Furthermore, the evaporator body has been coated with a type of resin that contains an antibacterial agent
in order to minimize the source of foul odor and the propagation of bacteria.
2. Condenser
The Prius has adopted sub-cool condenser in which a multi-flow condenser (consisting of two cooling por-
tions: a condensing portion and a super-cooling portion) and a gas-liquid separator (modulator) have been
integrated. This condenser has adopted the sub-cool cycle for its cooling cycle system to improve the heat
exchanging efficiency.
This condenser is integrated with the radiator to minimize the space they occupy in the engine compartment.
For details, see page 54 in the Engine Cooling System Section.
Sub-Cool Cycle
In the sub-cool cycle of the sub-cool condenser that has been adopted, after the refrigerant passes through
the condensing portion of the condenser, both the liquid refrigerant and the gaseous refrigerant that could
not be liquefied are cooled again in the super-cooling portion. Thus, the refrigerant is sent to the evaporator
in an almost completely liquefied state.

B02389
B02390
HEAT METHOD: When the problem seems to occur when the suspect area is heated. 2
NOTICE:3 WATER SPRINKLING METHOD:
(1)
(2)
4 OTHER: When a malfunction seems to occur when electrical load is excessive.When the malfunction seems to occur on a rainy day or in a
high±humidity condition. Heat the component that is the likely cause of the malfunction
with a hair dryer or similar object. Check to see if the malfunction
occurs.
Sprinkle water onto the vehicle and check to see if the malfunc-
tion occurs.
Turn on all electrical loads including the heater blower, head
lights, rear window defogger, etc. and check to see if the mal-
function occurs.ON HINT:
If a vehicle is subject to water leakage, the leaked water may
contaminate the ECU. When testing a vehicle with a water leak-
age problem, special caution must be taken.
Malfunc-
tion
Do not heat to more than 60 °C (140 °F). (Temperature
is limited not to damage the components.)
Do not apply heat directly to parts in the ECU. (1)
(2)
Never sprinkle water directly into the engine compart-
ment, but indirectly change the temperature and hu-
midity by applying water spray onto the radiator front
surface.
Never apply water directly onto the electronic compo-
nents. NOTICE: IN±36
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
2001 PRIUS (RM778U)

MA02G±02
MA±4
± MAINTENANCEUNDER HOOD
57 Author: Date:
2001 PRIUS (RM778U)
UNDER HOOD
GENERAL MAINTENANCE
1. GENERAL NOTES

Maintenance items may vary from country to country. Check the owner's manual supplement in which
the maintenance schedule is shown.

Every serice item in the periodic maintenance schedule must be performed.

Periodic maintenance service must be performed according to whichever interval in the periodic main-
tenance schedule occurs first, the odometer reading (miles) or the time interval (months).

Maintenance service after the last period should be performed at the same interval as before unless
otherwise noted.
2. WINDSHIELD WASHER FLUID
Check that there is sufficient fluid in the tank.
3. ENGINE COOLANT LEVEL
Check that the coolant level is between the ºFULLº and ºLOWº lines on the see±through reservoir.
4. RADIATOR AND HOSES
(a) Check that the front of the radiator is clean and not blocked with leaves, dirt or bugs.
(b) Check the hoses for cracks, kinks, rot or loose connections.
5. BRAKE FLUID LEVELS
Check that the brake fluid levels are near the upper level line on the see±through reservoirs.
6. CHECK TRANSAXLE OIL (FLUID)

Visually check the transaxle for oil (fluid) leakage.

If leakage is found, check for the cause and repair.
HINT:
Wait until the engine and motor cools down (approx. 30 min.) before checking the fluid level after extended
driving at high speeds, in hot weather, in heavy traffic or pulling a trailer.