2001 TOYOTA PRIUS heater

BODY ELECTRICAL ± AIR CONDITIONING
174BE06
Ex-HI
Blower
Air
Volume
LO
Low
Required Outlet
Air TemperatureHigh[C]
174BE07
HI
Calculated
Air Volume
LO
OFF[C]
Coolant Temperature (a) (b) (c) 168
Blower Control System
1) Blower Motor Startup Control
When the blower motor is started up, the blower voltage in the auto mode (low speed) is output to the
blower controller for 3 seconds. This is designed to protect the blower controller from a sudden startup
current surge.
2) Manual Control
Sets the blower speed according to operation of the blower switch.
3) Automatic Control
a. Stepless Air Volume Control
As shown on the right, when the AUTO
switch on the heater control panel is pushed,
the air conditioning ECU automatically reg-
ulates the voltage to the blower controller, in
accordance with the required outlet air tem-
perature, to deliver stepless air volume.
b. Warm-Up Control
When the coolant temperature detected by the engine coolant temperature sensor is below a predeter-
mined level and the air outlet is in the FOOT or BI-LEVEL mode, the blower does not operate. When
the coolant temperature reaches specified temperature (b), the blower motor operates at low speed.
When the coolant temperature is between specified temperature (b) to (c), the air flow calculation using
the engine coolant temperature sensor signal, and, the air flow calculation using the required outlet air
temperature are compared, and the lesser of the two is automatically selected as the air flow to be used.
When the coolant temperature reaches specified temperature (c) or more, the blower motor runs at high
speed. Moreover, when the coolant temperature is under specified temperature (a), and the warm-up
control is effected (blower motor off), the air outlet is switched to the DEF mode. Later, when the blower
motor turns on, the air outlet changes from the DEF mode to the FOOT or BI-LEVEL mode.

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)

IN0CI±02
± INTRODUCTIONTERMS
IN±51
2001 PRIUS (RM778U)
GLOSSARY OF SAE AND TOYOTA TERMS
This glossary lists all SAE±J1930 terms and abbreviations used in this manual in compliance with SAE rec-
ommendations, as well as their TOYOTA equivalents.
SAE
ABBREVIATIONSSAE TERMSTOYOTA TERMS
( )±±ABBREVIATIONS
A/CAir ConditioningAir Conditioner
ACLAir CleanerAir Cleaner, A/CL
AIRSecondary Air InjectionAir Injection (AI)
APAccelerator Pedal±
B+Battery Positive Voltage+B, Battery Voltage
BAROBarometric PressureHAC
CACCharge Air CoolerIntercooler
CARBCarburetorCarburetor
CFIContinuous Fuel Injection±
CKPCrankshaft PositionCrank Angle
CLClosed LoopClosed Loop
CMPCamshaft PositionCam Angle
CPPClutch Pedal Position±
CTOXContinuous Trap Oxidizer±
CTPClosed Throttle PositionLL ON, Idle ON
DFIDirect Fuel Injection (Diesel)Direct Injection (DI)
DIDistributor Ignition±
DLC1
DLC2
DLC3Data Link Connector 1
Data Link Connector 2
Data Link Connector 31: Check Connector
2: Total Diagnosis Comunication Link (TDCL)
3: OBD II Diagnostic Connector
DTCDiagnostic Trouble CodeDiagnostic Code
DTMDiagnostic Test Mode±
ECLEngine Control Level±
ECMEngine Control ModuleEngine ECU (Electronic Control Unit)
ECTEngine Coolant TemperatureCoolant Temperature, Water Temperature (THW)
EEPROMElectrically Erasable Programmable Read Only Memory
Electrically Erasable Programmable Read Only Memory
(EEPROM),
Erasable Programmable Read Only Memory (EPROM)
EFEEarly Fuel EvaporationCold Mixture Heater (CMH), Heat Control Valve (HCV)
EGRExhaust Gas RecirculationExhaust Gas Recirculation (EGR)
EIElectronic IgnitionTOYOTA Distributorless Ignition (TDI)
EMEngine ModificationEngine Modification (EM)
EPROMErasable Programmable Read Only MemoryProgrammable Read Only Memory (PROM)
EVAPEvaporative EmissionEvaporative Emission Control (EVAP)
FCFan Control±
FEEPROMFlash Electrically Erasable Programmable
Read Only Memory±
FEPROMFlash Erasable Programmable Read Only Memory±
FFFlexible Fuel±
FPFuel PumpFuel Pump
GENGeneratorAlternator
GNDGroundGround (GND)

MA02F±02
MA±2
± MAINTENANCEINSIDE VEHICLE
55 Author: Date:
2001 PRIUS (RM778U)
INSIDE VEHICLE
GENERAL MAINTENANCE
These are maintenance and inspection items which are considered to be the owner's responsibility.
They can be done by the owner or they can have them done at a service shop.
These items include those which should be checked on a daily basis, those which, in most cases, do not
require (special) tools and those which are considered to be reasonable for the owner to do.
Items and procedures for general maintenance are as follows.
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 service 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. LIGHTS
(a) Check that the headlights, stop lights, taillights, turn signal lights, and other lights are all working.
(b) Check the headlight aim.
3. WARNING LIGHTS AND BUZZERS
Check that all warning lights and buzzers function properly.
4. HORN
Check that it is working.
5. WINDSHIELD GLASS
Check for scratches, pits or abrasions.
6. WINDSHIELD WIPER AND WASHER
(a) Check operation of the wipers and washer.
(b) Check that the wipers do not streak.
7. WINDSHIELD DEFROSTER
Check that air comes out from the defroster outlet when operating the heater or air conditioner.
8. REAR VIEW MIRROR
Check that it is mounted securely.
9. SUN VISORS
Check that they move freely and are mounted securely.
10. STEERING WHEEL
Check that it has the specified freeplay. Be alert for changes in steering condition, such as hard steering,
excessive freeplay or strange noises.
11. SEATS
(a) Check that the seat adjusters operate smoothly.
(b) Check that all latches lock securely in any position.
(c) Check that the head restraints move up and down smoothly and that the locks hold securely in any
latch position.
(d) For fold±down seat backs, check that the latches lock securely.
12. SEAT BELTS
(a) Check that the seat belt system such as the buckles, retractors and anchors operate properly and
smoothly.
(b) Check that the belt webbing is not cut, frayed, worn or damaged.

PP2FC±02
± PREPARATIONENGINE MECHANICAL
PP±5
2001 PRIUS (RM778U)
EQUIPMENT
Abrasive compoundValve
Caliper gauge
CO/HC meter
Compression gauge
Connecting rod aligner
Cylinder gauge
Dial indicator
Dye penetrant
Engine tune±up tester
Groove cleaning toolPiston ring groove
Heater
Magnetic finger
Micrometer
Pin hole grinderPiston pin hole of piston
Piston ring compressor
Piston ring expander
Plastigage
Precision straight edge
Press
Ridge reamerCylinder
Soft brush
Solvent
Spring testerValve spring
Steel squareValve spring
Thermometer
Torque wrench
Torx wrench socket setStud bolt
TOYOTA hand held tester or OBDII scan tool
Valve seat cutter
V±block
Vernier calipers
Wire brushValve

PP2FH±02
± PREPARATIONCOOLING
PP±13
2001 PRIUS (RM778U)
EQUIPMENT
Belt tension gauge
HeaterThermostat
Radiator cap tester
ThermometerThermostat
Torque wrench
Vernier calipers

SS102±07
SS±12
± SERVICE SPECIFICATIONSSFI
134 Author: Date:
2001 PRIUS (RM778U)
SFI
SERVICE DATA
Fuel pumpResistance at 20°C (68°F)0.2 ± 3.0 W
InjectorResistance at 21 °C (68 °F)
Injection volume
Difference between each cylinder
Fuel leakage13.4 ± 14.2 W
36 ± 46 cm3 (2.1 ± 2.8 cu in.) per 15 sec.
10 cm3 (0.7 cu in.) or less
1 drop or less per 12 minutes
Mass air flow me-
ter
Resistance
at ±20°C (±4°F) THA ± E2
at 20°C (68°F) THA ± E2
at 60°C (140°F) THA ± E2
13.6 ± 18.4 kW
2.21 ± 2.69 kW
0.49 ± 0.67 kW
Throttle control
motorResistance
at 20°C (68°F) M+ ± M±
0.3 ± 100 W
Throttle position
sensorResistance
at 20°C (68°F) VC ± E2
1.2 ± 3.2 kW
VSV for EVAPResistance at 20°C (68°F)27 ± 33 W
VSV for CCVResistance at 20°C (68°F)25 ± 30 W
VSV for Purge
flow switching
valve
Resistance at 20°C (68°F)33 ± 39 W
VSV for HCACResistance at 20°C (68°F)33 ± 39 W
ECT sensorResistance at ±20°C (±4°F)
at 0°C (32°F)
at 20°C (68°F)
at 40°C (104°F)
at 60°C (140°F)
at 80°C (176°F)10 ± 20 kW
4 ± 7 kW
2 ± 3 kW
0.9 ± 1.3 kW
0.4 ± 0.7 kW
0.2 ± 0.4 kW
Vacuum sensor
for HCACPower sorce voltage4.5 ± 5.5 V
Vapor pressure
sevsorPower sorce voltage
Output voltage4.5 ± 5.5 V
3.0 ± 3.6 V
Heated
oxygen sensorHeater coil resistance at 20°C (68°F)11 ± 16 W
Accelerator pedal
position sensorResistance
at 20°C (68°F) Vcp
1 ± Ep1
Vcp2 ± Ep21.5 ± 6.0 kW
Fuel cut rpmFuel return rpm1,400 rpm

DI±8
± DIAGNOSTICSENGINE
2001 PRIUS (RM778U)
4. FAIL±SAFE CHART
If any of the following codes is recorded, the ECM enters fail±safe mode.
DTC No.Fail±Safe OperationFail±Safe Deactivation Conditions
P0100Ignition timing fixed at 5° BTDCReturned to normal condition
P0110Intake air temp. is fixed at 20°C (68°F)Returned to normal condition
P0115Engine coolant temp. is fixed at 80°C (176°F)Returned to normal condition
P0120VTA is fixed at 0°
The following condition must be repeated at least 2 times
consecutively
0.1 V
VTA
0.95 V
P0135
P0141The heater circuit in which an abnormality is detected is
turned offIgnition switch OFF
P0325Max. timing retardationIgnition switch OFF
P1300
P1305
P1310
P1315
Fuel cutIGF signal is detected for 2 consecutive ignitions
5. CHECK FOR INTERMITTENT PROBLEMS
TOYOTA hand±held tester only:
By putting the vehicle's ECM in check mode, 1 trip detection logic is possible instead of 2 trip detection logic
and sensitivity to detect open circuits is increased. This makes it easier to detect intermittent problems.
(1) Clear the DTC (See step 3).
(2) Set the check mode (See step 3).
(3) Perform a simulation test (See page IN±30).
(4) Check the connector and terminal (See page IN±41).
(5) Handle the connector (See page IN±41).
6. BASIC INSPECTION
When the malfunction code is not confirmed in the DTC check, troubleshooting should be performed in the
order for all possible circuits to be considered as the causes of the problems. In many cases, by carrying
out the basic engine check shown in the following flow chart, the location causing the problem can be found
quickly and efficiently. Therefore, use of this check is essential in engine troubleshooting.
1 Is battery positive voltage 11 V or more when engine is stopped?
NO Charge or replace battery.
YES
2 Does engine start?
NO Go to step 6.
YES