heating TOYOTA PRIUS 2001 Service Repair Manual

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

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.

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
182BE15
External Air
Internal AirFresh, dry external air
to the upper area
Warm internal air to
the footwell area
181BE38
Airflow During 2-way Flow Control
Internal
External
Door
Internal
AirExternal
AirInternal
AirDEF
EvaporatorFA C E
Mode Door
FOOT and Rr FOOT Heater
Core Air Mix Door
External Air
Internal Air 154
CONSTRUCTION AND OPERATION
1. Air Conditioning Unit
Air Conditioning Assembly
1) General
A semi-center location air conditioning unit, in which the multi tank type evaporator and straight flow
heater core are placed in the vehicle's longitudinal direction, has been adopted.
Both heating and demisting performances are realized by adopting the 2-way flow heater type air
conditioning unit.
This unit, which introduces external air and internal air simultaneously, discharges warm internal air
to the footwell area, and the fresh, dry external air to the upper area. Thus, it realizes both excellent
heating performance and demisting performance.
2) Construction
A partition plate divides the inside of the air conditioning unit into two parts, the external air passage,
and the internal air passage. Thus, by controlling the external air door and the internal air door separately,
the external air and internal air are introduced into the cabin in the following three modes: fresh-air mode,
recirculation mode, and fresh-air / recirculation (2-way flow) mode.

± DIAGNOSTICSENGINE
DI±65
2001 PRIUS (RM778U)
DTC P0300 Random/Multiple Cylinder Misfire Detected
DTC P0301 Cylinder 1 Misfire Detected
DTC P0302 Cylinder 2 Misfire Detected
DTC P0303 Cylinder 3 Misfire Detected
DTC P0304 Cylinder 4 Misfire Detected
CIRCUIT DESCRIPTION
Misfire: The ECM uses the crankshaft position sensor and camshaft position sensor to monitor changes in
the crankshaft rotation for each cylinder.
The ECM counts the number of times the engine speed change rate indicates that misfire has occurred. And
when the misfire rate equals or exceeds the count indicating that the engine condition has deteriorated, the
MIL lights up.
If the misfire rate is high enough and the driving conditions will cause catalyst overheating, the MIL blinks
when misfiring occurs.
DTC No.DTC Detecting ConditionTrouble Area
P0300Mi fi i f d li d i d t t d d i ti l

Open or short in engine wire

Connector connection

Vacuum hose connection

I
gnition systemP0300
P0301
P0302
P0303
P0304
Misfiring of random cylinders is detected during any particular
200 or 1,000 revolutions
For any particular 200 revolutions for the engine, misfiring is
detected which can cause catalyst overheating
(This causes MIL to blink)

Ignition system

Injector

Fuel pressure

Manifold absolute pressure sensor

En
gine coolant temp. sensorP0304(This causes MIL to blink)
Engine coolant tem. sensor

Compression pressure

Valve clearance

Valve timing

ECM
HINT:

When the 2 or more codes for a misfiring cylinder are recorded repeatedly but no random misfire code
is recorded, it indicates that the misfires were detected and recorded at different times.

There is a case where the cylinder other than memorized has an accidental fire (the cylinder which is
one ahead of fired cylinder), so. at the time of checking all the checking items and if there is no ab-
normality, check the cylinder which is different from the recorded cylinder as fired.
DI6V8±03

± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±195
2001 PRIUS (RM778U) MG1 CURRENT W
Electric current of MG1 W phase
MG1 INV TEMP HITemperature of inverter MG1 is high
MG1 REVMG1 revolution
MG1 TEMPMotor temperature of MG1
MG1 TEMP HIGHTemperature fo MG1 is too high
MG2 TEMP HIGHTemperature fo MG2 is too high
MG1 CURRENT VElectric cuurent of MG1 is V phase
MG1 CURRENT WElectric cuurent of MG1 is W phase
MG1 INV TEMP HITemperature of inverter MG1 is higt
MG1 REVMG1 revolution
MG1 TEMPMotor temperature of MG1
MG1 TEMP HIGHTemperature of MG1 is high
MG1 TORQMG1 torque
MG2 CURRENT VElectric cuurent of MG2 is V phase
MG2 CURRENT WElectric cuurent of MG2 is W phase
MG2 INV TEMP HITemperature of inverter MG2 is higt
MG2 REVMG2 revolution
MG2 TEMPMotor temperature of MG2
MG2 TEMP HIGHTemperature of MG2 is high
MG2 TORQMG2 torque
N RANGE OVR TIMELeaving shift gear into N position over a period of time
N RANGE CTRL1N position control due to incomplete shift gears
N RANGE CTRL2N position control due to rapid shift gear (D±R)
OCCURRENCE ORDROrder in which the trouble occurs
OCCURRNCE TRIPNumber of trips when this error occurred
OUTPUT STOPOutput stop
OUTPUT V OVEROutput voltage is too high
OVER CURRENTElectric current of the batytery is too high
OVER VOLTAGEVoltage of the battery is too high
OVR HEAT PRTECTOverheat protection
POWER RQSTPower output requested by HV ECU
PWR RESOURCE IBPower resource IB
PWR RESOURCE VMpower resource VM
RAPID SPD CHANGVehicle speed is changed too rapidly
REGEN EXEC TORQTorque volue of regenerative brake
REGEN IH FACTORInhibiting factor of regeneration
REGEN RQST TORQTorque valueof regenerative brake requested by HV ECU
REGN BRK INEFCTRegenerative brake is ineffective
RESIST OVR HEATRestriction resist is overheating
SG B IN REDUCINShifting gear into ºBº in reducing the speed
SG N IN REDUC/PShifting gear into ºNº reducing the speed
SHIFT BEF READYShifting gear before ºREADYº light turns on
SHIFT POSITIONShift position
SHIFT SENSOR1Shift sensor 1
SHIFT SENSOR2Shift sensor 2
SOCStated of charge

± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±203
2001 PRIUS (RM778U)DTC NO.
INF. CodeDetection ItemDetecting Condition
247GND short in motor temperature sensor
248Motor Temperature SensorMotor temperature sensor malfunction
249
Motor Tem erature Sensor
MalfunctionOpen or +B short in motor temperature sensor
250Motor temperature sensor performance problem
253Generator resolver inter±phase short
P3120
254Generator Resolver Malfunc-
Generator resolver inter±phase short (When there is a history that the
state of malfunction continued during inverter fail safe mode)
P3120255
Generator Resolver Malfunc
tionOpen or short in generator resolver circuit
256Open or short in generator resolver circuit (When there is a history that the
state of malfunction continued during inverter fail safe mode)
257GND short in generator temperature sensor
258Generator Temperature Sen-Generator temperature sensor malfunction
259
Generator Tem erature Sen
sor MalfunctionOpen or +B short in generator temperature sensor
260Generator temperature sensor performance problem
263+B short in DCDC converter NODD wiring
264DCDC Converter MalfunctionDCDC converter malfunction
265
DCDC Converter Malfunction
Open or GND short in DCDC converter NODD wiring
266Open or GND short in inverter voltage signal circuit
267+B short in inverter voltage signal circuit
268Inverter voltage signal is inconsistent with battery voltage
269VM MalfunctionInverter voltage sensor malfunction
270
Abnormality of line connection of inverter voltage signal circuit (When there
is a history that the state of malfunction continued during inverter fail safe
mode)
272Motor PWN Line Connection
MalfunctionAbnormality of line connection of motor PWM (When there is a history that
the state of malfunction continued during inverter fail safe mode)
273Motor Inverter Gate Malfunc-
tionMotor inverter malfunction
P3125274Mt I t T tOpen or +B short in motor inverter temperature sensor
275Motor Inverter TemperatureGND short in motor inverter temperature sensor
276S M lf tiMotor inverter temperature sensor malfunction
277Sensor MalfunctionMotor inverter temperature sensor performance problem
278+B short in motor inverter stop signal circuit
279Over voltage of inverter
280Motor Inverter SinvOpen or GND short in motor inverter stop signal circuit
281
Motor Inverter Sinv
Voltage drop of inverter power source
282Inverter circuit broken
283+B short in motor inverter fail signal circuit
284Inverter overheating
285Motor Inverter FinvOpen or GND short in motor inverter fail signal circuit
286
Motor Inverter Finv
Inverter circuit broken
287Inverter internal short

DI±204
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)DTC NO.
INF. CodeDetection ItemDetecting Condition
288Motor inverter current sensor malfunction (V phase sub sensor)
289Open in motor inverter current sensor (V phase sub sensor)
290Motor inverter current sensor malfunction (V phase main sensor)
291(when there is a history that the state of malfunction continued during in-
verter fail safe mode)
292Open in motor inverter current sensor (V phase main sensor)
293(when there is a history that the state of malfunction continued during in-
verter fail safe mode)
294Mt I t C tSMotor inverter current sensor V phase performance problem
295
Motor Inverter Current Sen-
sor Malfunction(when there is a history that the state of malfunction continued during in-
verter fail safe mode)
296Motor inverter current sensor malfunction (W phase sub sensor)
297Open in motor inverter current sensor (W phase sub sensor)
298Motor inverter current sensor malfunction (W phase main sensor)
299(when there is a history that the state of malfunction continued during in-
verter fail safe mode)
300Open in motor inverter current sensor (W phase main sensor)
301(when there is a history that the state of malfunction continued during in-
verter fail safe mode)
302Mt I t C tSMotor inverter current sensor W phase performance problem
303
Motor Inverter Current Sen-
sor Malfunction(when there is a history that the state of malfunction continued during in-
verter fail safe mode)
304Motor Gate Shutdown Signal+B short in motor gate shutdown signal circuit
P3125305
Motor Gate Shutdown Signal
Line Connection MalfunctionOpen or GND short in motor gate shutdown signal circuitP3125
306Failure in Monitoring Motor
Torque PerformanceFailure in monitoring motor torque performance
307Abnormal Current Value of
MotorAbnormal current value of motor
308Detection of Collision SignalInput of collision signal from airbag or inverter
309Motor PWM Line Connection
MalfunctionOpen or short in generator inverter switching wiring (GUU, GVU, GWU)
311Generator Inverter Malfunc-
tionGenerator inverter malfunction
312Open or +B short in generator inverter temperature sensor
313Generator Inverter Tempera-GND short in generator inverter temperature sensor
314
Generator Inverter Tem era
ture Sensor MalfunctionGenerator inverter temperature sensor malfunction
315Generator inverter temperature sensor performance problem
316+B short in generator inverter stop signal circuit
317Over voltage of inverter
318Generator Inverter SinvOpen or GND short in generation inverter stop signal circuit
319
Generator Inverter Sinv
Voltage drop of inverter power source
320Inverter circuit broken
321+B short in generator inverter fail signal circuit
322Inverter overheating
323Generator Inverter FinvOpen or GND short in generator inverter fail signal circuit
324
Generator Inverter Finv
Inverter circuit broken
325Inverter internal short

A14121
Motor Generator No. 2Hybrid Vehicle
Control ECU
MMTG
MMT3
M4
1
M4R±W
MMTG
MMT GR9
H10
2
H10 DI±258
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
CIRCUIT DESCRIPTION
The HV ECU checks the motor temperature and controls the load limitation in order to prevent the motor from
overheating. Also, it detects the abnormality of the line connection of the motor temperature sensor and mal-
function of the sensor itself.
DTC P3120 ± Information code 247, 249
INF. Code.Detecting ConditionTrouble Area
247GND short in motor temperature sensor
HV transaxle
249Open or +B short in motor temperature sensor

HV transaxle

Wire harness
WIRING DIAGRAM

A14121
Motor Generator No. 1Hybrid Vehicle
Control ECU
4
M2
9
M2B±R
GMT
GMTG G±W1
H10
8
H10 GMT
GMTG DI±264
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
CIRCUIT DESCRIPTION
The HV ECU checks the generator temperature and controls the load limitation in order to prevent the gener-
ator from overheating. Also, it detects the abnormality of the line connection of the generator temperature
sensor and the malfunction of the sensor itself.
DTC P3120 ± Information code 257, 259
INF. Code.Detecting ConditionTrouble Area
257GND short in generator temperature sensor
HV transaxle
259Open or +B short in generator temperature sensor

HV transaxle

Wire harness
WIRING DIAGRAM