2001 TOYOTA PRIUS ESP

BODY ELECTRICAL ± AIR CONDITIONING
182BE50
Large
Target
Damper
Opening
Angle
Small
Large Small
Tentative Damper Opening Angle167
Calculation of Required Outlet Air Temperature (TAO: Temperature Air Outlet)
After receiving the signals from the sensors and the temperature control switch setting, the air conditioning
ECU uses the formula shown below to calculate the required outlet air temperature, to regulate the servomo-
tors and blower motor. This is an outlet air temperature that is required in maintaining the set temperature
in a stable manner.
TAO=KSETx TSET±Kr x TR±KAMx TAMdisp±KsxTS+C±TCTA O = KSET x TSET ± Kr x TR ± KAM x TAMdisp ± Ks x TS + C ± TC
KSET= Setting Temperature Coefficient TSET = Setting Temperature
Kr = Room Air Temperature Coefficient TR = Room Air TemperatureKr= Room Air Temperature CoefficientTR= Room Air Temperature
K
AM= Ambient Air Temperature Coefficient TAMdisp = Ambient Air TemperatureAMppp
Ks = Solar Radiation Coefficient TS = Solar Radiation
C = Correct Constant TC = Compressor ON / OFF CorrectC= Correct ConstantTC= Compressor ON / OFF Correct
= Constant
Temperature Control System
1) Air Mix Damper Control
In response to the temperature control switch setting, the required ambient temperature, evaporator tem-
perature sensor, and engine coolant temperature sensor compensations are used by the air mix damper
control to calculate a tentative damper opening angle, through an arithmetic circuit in the air mix damper,
to arrive at a target damper opening angle.

Calculating the Target Damper Opening 

BODY ELECTRICAL ± AIR CONDITIONING
182BE51
Hi
Lo Blower
Air
Volume
Small Large
Amount of Sunligt
182BE28182BE29
1
0
Small Large
Vehicle Speed Fresh Air
Recirculation
182BE52
Outlet Air
Half
Inlet Air
Low High
TAO (Temperature Air Outlet) 170
d. Sunlight Air Flow Control
Controls the blower speed in accordance
with the intensity of the sunlight when the air
outlet mode is at FACE or BI-LEVEL. The
blower low speed can be adjusted up to 4
steps, in response to the sunlight signal re-
ceived from the solar sensor.
2-Way Flow Mode Control
At the time of selecting FRESH mode, air conditioning ECU will judge it as 2-way flow mode when the
blower outlet is selected to FOOT or FOOT / DEF, the tentative air mix damper opening angle is above the
specified valve (MAX HOT), and either the blower volume is more than the specified volume or the vehicle
speed is less than the specified speed.
Half Inlet Air Mode Control
At the time of selecting FRESH mode, air condi-
tioning ECU will judge it as half inlet air mode
when the blower outlet mode is selected to FACE
or BI-LEVEL and TAO (Temperature Air Out-
let) is more than the specified temperature, and
operates both outlet air introduction and inlet air
circulation at the same time.

BODY ELECTRICAL ± ACCESSORIES
151LBE24
GPS Sateilites
Difference
Difference
Difference
Difference181
5) Detecting the Vehicle Position
The navigation ECU calculates the position based on the principle of a 3-point measurement.
The GPS satellites are equipped with high-precision clocks. Thus, the satellites are able to transmit con-
tinuous orbit signals and radiowave transmission time signals.
The navigation ECU also contains a clock, which can understand the radiowave time signals that are re-
ceived from the satellites.
As a result, the length of time that is taken by the radiowaves to arrive from the satellites to the antenna
can be determined. Thus, the lengths of time that elapse for the radiowaves of the 4 satellites to reach
the antenna are measured. Each of these lengths of time are multiplied by the luminous flux (the rate of
transmission of luminous energy: approximately 300,000 km per second), the results of which are the
distances from the satellites to the antenna. Because the positions of the GPS satellites are known by their
signals, the receiving point (vehicle position) can be rendered as the point in which the 4 spheres (of
which the centers are the respective satellites) converge.
However, due to the differences that exist between the clocks of the satellite and the ECU, the 4 spheres
do not converge at a single point. Therefore, the ECU uses another satellite to calculate the point at which
the 4 spheres converge at a single point and corrects its internal clock. As a result, the ECU determines
the vehicle position and adjusts its internal clock to the clocks of the satellites.

DTC No.
Indicates the diagnostic trouble code.

Page or Instructions
Indicates the page where the inspection procedure
for each circuit is to be found, or gives instructions
for checking and repairs.

Detection Item
Indicates the system of the problem or
contents of the problem.
Trouble Area
Indicates the suspect area of the
problem.
Mass Air Flow Circuit MalfunctionDetection Item

Open or short in mass air flow meter circuit

Mass air flow meter

ECM DTC No.
(See page)Trouble AreaMIL* MemoryP0100
(DI±24)
P0101
(DI±28)
P0115
(DI±33)
Open or short in intake air temp. sensor
circuit

Intake air temp. sensor

ECM Intake Air Temp. Circuit
Malfunction P0110
(DI±29)

Open or short in engine coolant temp. sensor circuit

Engine coolant temp. sensor

ECM
Throttle/ Pedal Position Sensor/Switch
ºAº Circuit MalfunctionEngine Coolant Temp.
Circuit Malfunction

Open or short in throttle position sensor circuit

Throttle position sensor

ECM
DTC CHART (SAE Controlled)
HINT:
Parameters listed in the chart may not be exactly the same as your reading due to the type of instrument or other
factors.
If a malfunction code is displayed during the DTC check mode, check the circuit for that code listed in the table
below. For details of each code, turn to the page referred to under the ºSee pageº for the respective ºDTC No.º
in the DTC chart.
Mass Air Flow Circuit
Range/ Performance Problem
Mass air flow meter

Throttle position sensor Throttle/ Pedal Position Sensor/ Switch
ºAº Circuit Range / Performance Prob-
lem P0116
(DI±37)Engine Coolant Temp.
Circuit Range/ Performance Problem
Engine coolant temp. sensor

Cooling system
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN±37
2001 PRIUS (RM778U)
4. DIAGNOSTIC TROUBLE CODE CHART
The inspection procedure is shown in the table below. This table permits efficient and accurate troubleshoot-
ing using the diagnostic trouble codes displayed in the diagnostic trouble code check. Proceed with trouble-
shooting in accordance with the inspection procedure given in the diagnostic chart corresponding to the
diagnostic trouble codes displayed. The engine diagnostic trouble code chart is shown below as an example.

MA02E±02
± MAINTENANCEOUTSIDE VEHICLE
MA±1
54 Author: Date:
2001 PRIUS (RM778U)
OUTSIDE 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.

Failure to do even one item an cause the engine to run poorly and increase exhaust emissions.
2. TIRES
(a) Check the pressure with a gauge. If necessary, adjust.
(b) Check for cuts, damage or excessive wear.
3. WHEEL NUTS
When checking the tires, check the nuts for looseness or for missing nuts. If necessary, tighten them.
4. TIRE ROTATION
Check the owner's manual supplement in which the maintenance schedule is shown.
5. WINDSHIELD WIPER BLADES
Check for wear or cracks whenever they do not wipe clean. If necessary, replace.
6. FLUID LEAKS
Check underneath for leaking fuel, oil, water or other fluid.
7. DOORS AND ENGINE HOOD
(a) Check that all doors including the trunk lid operate smoothly, and that all latches lock securely.
(b) Check that the engine hood secondary latch secures the hood from opening when the primary latch
is released.

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.

P21235
MA049±01
F12933
F12919
MA±8
± MAINTENANCEBODY
61 Author: Date:
2001 PRIUS (RM778U)
BODY
INSPECTION
1. TIGHTEN BOLTS AND NUTS ON CHASSIS AND BODY
Tighten these parts:

Front seat mount bolts
Torque: 37 N´m (375 kgf´cm, 27 ft´lbf)

Front suspension member±to±body mounting bolts
Torque:
Bolt A: 113 N´m (1,150 kgf´cm, 83 ft´lbf)
Bolt B: 157 N´m (1,600 kgf´cm, 116 ft´lbf)

Rear suspension member±to±body mounting nuts
Torque: 90 N´m (918 kgf´cm, 66 ft´lbf)
2. FINAL INSPECTION
(a) Check the operation of the body parts:

Hood:
Auxiliary catch operate properly
Hood locks securely when closed

Front and rear doors:
Door lock operates properly
Doors close properly

Luggage compartment door:
Door lock operates properly

Seats:
Seat adjusts easily and locks securely in any posi-
tion
Front seat back locks securely in any position
Folding±down rear seat backs lock securely
(b) Road test:

Check the engine and chassis for abnormal noises.

Check that the vehicle does not wander or pull to
one side.

Check that the brake work properly and do not drag.
(c) Be sure to deliver a clean car. especially check:

Steering wheel

Shift lever knob

All switch knobs

Door handles

Seats

± DIAGNOSTICSENGINE
DI±13
2001 PRIUS (RM778U)O2 LR B1, S1 *
Heated Oxygen Sensor Lean Rich Bank 1, Sen-
sor 1 Response time for oxygen sensor output to
switch from lean to rich
Idling after warmed up: 0 ± 1,000 msec.
O2 RL B1, S1 *
Heated Oxygen Sensor Rich Lean Bank 1, Sen-
sor 1 Response time for oxygen sensor output to
switch from rich to lean
Idling after warmed up: 0 ± 1,000 msec.
*: If no conditions are specifically stated for ºldlingº, it means the shift lever is at P position, the A/C switch
is OFF and all accessory switches are OFF.