2001 TOYOTA PRIUS torque

CHASSIS ± STEERING
182CH70
182CH71
182CH72
Torque
Sensor
Rack and
PinionDC Motor
Reduction Mechanism
Motor
Shaft
Stator
Rotor
Pinion Gear
Motor Shaft
DC Motor
Ring Gear
Pinion Shaft125
4. Construction and Operation of Main Components
Steering Gear
1) General
The steering gear consists of the rack and pin-
ion, DC motor, reduction mechanism, and
torque sensor. The front suspension compo-
nents have been optimized to reduce the load
on the DC motor. Also, the components have
been optimally allocated to ensure ample rack
travel and wheel turning angle, resulting in
excellent cornering performance.
2) DC Motor
The DC motor is mounted on the gear hous-
ing. The DC motor consists of the motor shaft
that is integrated with the hypoid pinion to
transmit the torque that has been generated by
the drive force of DC motor to the pinion
shaft, the rotor and stator.
3) Reduction Mechanism
A reduction mechanism that transmits the
rotation of the motor to the pinion shaft has
been mounted on the steering gear. The reduc-
tion mechanism consists of the ring gear that
is secured to the pinion shaft and the pinion
gear that is integrated with the motor shaft.
The power assist of the motor is transmitted
by the reduction mechanism to the pinion
shaft, which provides power assist to the
steering effort.

CHASSIS ± STEERING
182CH73
Contact 1 Resistor 1
Upward
Resistor 2
DownwardContact 2
Contacts Torque
Sensor
Resistor
182CH74
Resistor
Basic
Position
Contact
Straightline 126
4) Torque Sensor
A torque sensor that detects the torque that is input by the steering wheel has been mounted on the pinion
shaft. The torque sensor has been integrated with the pinion shaft, and the pinion shaft's input and output
shafts are linked via the torsion bar. Resistors for the torque sensor are mounted on the input shaft of the
pinion shaft, and contacts for the torque sensor are mounted on the output shaft of the pinion shaft. Oper-
ating the steering wheel causes the torsion bar to twist, creating a displacement between the pinnion
shaft's input and output. Two systems of torque sensors detect this displacement in the form of voltage
changes, which are then output to the EMPS ECU.
i) Straightline Driving
If the vehicle is driven straight and the driv-
er does not turn the steering, torque is not
generated in the pinion shaft's input shaft.
Thus, the torsion bar does not twist, and no
changes in resistance occur in the torque
sensor.

CHASSIS ± STEERING
182CH95
182CH76
Twist Angle
Basic Position
Cornering
Torque
[V]
Voltage
Voltage difference between
outputs 1 and 2 during
straight line driving (0)
Torque Sensor 2
Torque Sensor 1
0 ±+
Right Turn Left Turn127
ii) Steering to the right
When the driver turns the steering to the
right, the steering torque is transmitted to
the pinion shaft's input shaft, causing the
input shaft to rotate. Because the reaction
force of the ground surface acts on the rack
bar, the torsion bar that links the input shaft
and the pinion twists until a torque that
equalizes with the reaction force is gener-
ated. Thus, a relative displacement is
created between the resistor that is secured
onto the input shaft and the contact that is
secured onto the pinion shaft's output shaft.
As a result, the resistance changes, causing
the torque sensor's outputs 1 and 2 to
change as shown in the right diagram. The
EMPS ECU uses this voltage difference to
calculate the power assist torque to drive
the DC motor, thus generating a power as-
sist force in the pinion shaft via the reduc-
tion mechanism.
iii) Steering Hold Condition
The torsion bar shift to a position in which the sum of the driver's steering torque and the motor's assist
torque equalizes with the reaction force of the ground surface in order to maintain the steering holding
condition.
EMPS ECU
1) EMPS Control
The EMPS ECU receives signals from various sensors, judges the current vehicle condition, and deter-
mines the assist ampere to be applied to the DC motor accordingly.
2) Self-Diagnosis
If the EMPS ECU detects a malfunction in the EMPS system, the warning light that corresponds to the
function in which the malfunction has been detected lights up to alert the driver of the malfunction.
The EMPS ECU will also store the codes of the malfunctions. The DTCs (Diagnostic Trouble Codes)
can be accessed through the use of a hand-held tester. For details, see the 2001 Prius Repair Manual (Pub.
No. RM778U).
3) Fail-Safe
If the EMPS ECU detects a malfunction in the EMPS system, the system basically turns OFF the power
to prohibit power assist. As a result, the EMPS system operates the same way as manual steering.
However, depending on the location in which the malfunction occurred, power assist may be provided
by reducing the power assist amperage or by fixing the amount of power assist without relying on the
vehicle speed.

BODY ELECTRICAL ± ACCESSORIES
182BE46
Cruise Control Switch Signal
Brake Cancel Signal
(Stoplight Switch)
Accelerator Opening Angle Signal
(Accelerator Pedal Position Sensor)
Shift Position Signal
(Sift Position Sensor)
Brake ECUHV ECU
Cruise Control Area

Switch Input Value

Processing

Required Vehicle Speed

Calculation
Hybrid Control Area

Required Torque

Calculation

Drive Force Distribution

between Engine and
Electric Motor
Indicator Light
ECM
Inverter189
CRUISE CONTROL SYSTEM
1. General
The Prius has adopted a cruise control system that uses the hybrid system, and it is offered as an option. This
system, which is controlled by the HV ECU that is integrated with the cruise control ECU, operates the ve-
hicle through an optimal combination of the drive forces of the electric motor and the engine in accordance
with the setting on the cruise control switch.
2. Construction
The cruise control system mainly consists of an HV ECU, cruise control switches, indicator, stoplight switch,
accelerator pedal position sensor, and the shift position sensor.
The table below shows each of the functions.
Item
Function
HV ECUControls all the functions of the cruise control system in accordance with the
signals from the sensors.
Cruise Control Main
SwitchCruise control system's ON / OFF signal requirement.
Cruise Control Switch
A three-directional switch that provides the SET / COAST, RESUME /
ACCEL, and CANCEL functions. It requires the functions and settings in
accordance with its operations.
Indicator LightIt is provided in the combination meter to display whether the system is ON
or OFF.
Stop Light SwitchDetects that the driver has stepped on the brake pedal.
Accelerator Pedal
Position SensorDetects the accelerator pedal opening angle.
Shift Position SensorDetects the shift position.

APPENDIX
5
10
15
20
25
30
35
40
45
50
55
60
65
70
Area
Item
Major Dimensions & Vehicle Weights Performance Engine Engine
Chassis
Electrical
192
MAJOR TECHNICAL SPECIFICATIONS
U.S.A. and CanadaBody Type4-Door SedanVehicle GradeÐModel CodeNHW11L-AEEEBANHW11L-AEEEBKLength mm (in.)4305 (169.5)u
OverallWidth mm (in.)1695 (66.7)uOverallHeight mm (in.)1465 (57.6)uWheel Base mm (in.)2550 (100.4)u
TreadFront mm (in.)1475 (58.1)uTreadRear mm (in.)1480 (58.3)u
Effective Head RoomFront mm (in.)985 (38.8)uEffective Head RoomRear mm (in.)942 (37.1)u
Effective Leg RoomFront mm (in.)1047 (41.2)uEffective Leg RoomRear mm (in.)899 (35.4)u
Shoulder RoomFront mm (in.)1342 (52.8)uShoulder RoomRear mm (in.)1325 (52.2)u
OverhangFront mm (in.)815 (32.1)uOverhangRear mm (in.)940 (37.0)uMin. Running Ground Clearance mm (in.)125 (4.9)uAngle of Approach degrees145uAngle of Departure degrees225uFront kg (lb)770 (1700)u
Curb WeightRear kg (lb)485 (1065)uCurb WeightTotal kg (lb)1255 (1765)uFront kg (lb)890 (1965)u
Gross Vehicle WeightRear kg (lb)750 (1650)uGross Vehicle WeightTotal kg (lb)1640 (3615)uFuel Tank Capacity
(US. gal., lmp.gal.)45* (11.9, 9.9)uLuggage Compartment Capacity m3 (cu.ft.)0.39 (137.7)uMax. Speed km/h (mph)160 (99.4)uMax. Cruising Speed km/h (mph)160 (99.4)u
Acceleration0 to 100 km/h sec.12.7uAcceleration0 to 400 m sec.19.0u1st Gear km/h (mph)ÐÐ
Max. Permissible2nd Gear km/h (mph)ÐÐMax. Permissible
Speed3rd Gear km/h (mph)ÐÐp
4th Gear km/h (mph)ÐÐ
Min. Turning RadiusWall to Wall m (ft.)10.2 (33.5)uMin. Turning Radius
(Outside Front)Curb to Curb m (ft.)9.4 (30.8)uEngine Type1NZ-FXEuValve Mechanism16-Valve, DOHCuBore y Stroke mm (in.)75.0 y 84.7 (2.95 y 3.33)uDisplacement cm3 (cu.in.)1497 (91.4)uCompression Ratio13.0uCarburetor TypeSFIuResearch Octane No. RON95uMax. Output (EEC) kW/rpm (HP@rpm)52/4500 (70@4500)uMax. Torque (EEC) N´m/rpm (lb-ft@rpm)111/4200 (82@4200)uBattery Capacity (5HR) Voltage & Amp. Hr.12 ± 28uAlternator Output WattsÐÐStarter Output kWÐÐClutch TypeÐÐTransaxle TypeP111uIn FirstÐÐIn SecondÐÐ
Transmission GearIn ThirdÐÐTransmission Gear
RatioIn FourthÐÐIn FifthÐÐIn ReverseÐÐCounter Gear RatioÐÐDifferential Gear Ratio (Final)3.905u
Brake TypeFrontVentilated DiscuBrake TypeRearL.T. DrumuParking Brake TypeL.T. DrumuBrake Booster Type and Size in.HydraulicuProportioning Valve TypeP-Valveu
Suspension TypeFrontMacPherson StrutuSuspension TypeRearTorsion Beanu
Stabilizer BarFrontSTDuStabilizer BarRearSTDuSteering Gear TypeRack and PinionuSteering Gear Ratio (Overall)16.4~18.3uPower Steering TypeElectric Motoru
*: EPA / CARB ORVR Test conditions

IN00U±36
N17080
Filler Cap
Float
Reservoir
 Grommet
Clip
Slotted Spring Pin
: Specified torque
 Non±reusable partCylinder
Piston
Push Rod
Washer
Snap Ring
Boot
 Gasket
Lock Nut
Clevis Pin
Clevis
N´m (kgf´cm, ft´lbf)
12 (120, 9)
15 (155, 11)
± INTRODUCTIONHOW TO USE THIS MANUAL
IN±1
1 Author: Date:
2001 PRIUS (RM778U)
HOW TO USE THIS MANUAL
GENERAL INFORMATION
1. INDEX
An INDEX is provided on the first page of each section to guide you to the item to be repaired. To assist you
in finding your way through the manual, the section title and major heading are given at the top of every page.
2. PRECAUTION
At the beginning of each section, a PRECAUTION is given that pertains to all repair operations contained
in that section.
Read these precautions before starting any repair task.
3. TROUBLESHOOTING
TROUBLESHOOTING tables are included for each system to help you diagnose the problem and find the
cause. The fundamentals of how to proceed with troubleshooting are described on page IN±30.
Be sure to read this before performing troubleshooting.
4. PREPARATION
Preparation lists the SST (Special Service Tools), recommended tools, equipment, lubricant and SSM (Spe-
cial Service Materials) which should be prepared before beginning the operation and explains the purpose
of each one.
5. REPAIR PROCEDURES
Most repair operations begin with an overview illustration. It identifies the components and shows how the
parts fit together.
Example:

Illustration:
what to do and where
21. CHECK PISTON STROKE OF OVERDRIVE BRAKE
(a)
Task heading : what to do
SST 09350±30020 (09350±06120)
Set part No. Component part No.
Detailed text : how to do task
(b)
Piston stroke: 1.40 1.70 mm (0.0551 0.0669 in.)
Specification
Place SST and a dial indicator onto the overdrive brake pis-
ton as shown in the illustration.
Measure the stroke applying and releasing the compressed
air (392 785 kPa, 4 8 kgf/cm
2 or 57 114 psi) as shown
in the illustration. IN±2
± INTRODUCTIONHOW TO USE THIS MANUAL
2 Author: Date:
2001 PRIUS (RM778U)
The procedures are presented in a step±by±step format:

The illustration shows what to do and where to do it.

The task heading tells what to do.

The detailed text tells how to perform the task and gives other information such as specifications
and warnings.
Example:
This format provides the experienced technician with a FAST TRACK to the information needed. The upper
case task heading can be read at a glance when necessary, and the text below it provides detailed informa-
tion. Important specifications and warnings always stand out in bold type.
6. REFERENCES
References have been kept to a minimum. However, when they are required you are given the page to refer
to.
7. SPECIFICATIONS
Specifications are presented in bold type throughout the text where needed. You never have to leave the
procedure to look up your specifications. They are also found in Service Specifications section for quick ref-
erence.
8. CAUTIONS, NOTICES, HINTS:

CAUTIONS are presented in bold type, and indicate there is a possibility of injury to you or other
people.

NOTICES are also presented in bold type, and indicate the possibility of damage to the components
being repaired.

HINTS are separated from the text but do not appear in bold. They provide additional information to
help you perform the repair efficiently.
9. SI UNIT
The UNITS given in this manual are primarily expressed according to the SI UNIT (International System of
Unit), and alternately expressed in the metric system and in the English System.
Example:
Torque: 30 N´m (310 kgf´cm, 22 ft´lbf)

BE1367
Medium Current Fuse and High Current Fuse
Equal Amperage Rating
V00076
Abbreviation Part Name Symbol Illustration
FUSE
MEDIUM CURRENT FUSE
HIGH CURRENT FUSE
FUSIBLE LINK
CIRCUIT BREAKERFUSE
M±FUSE
H±FUSE
FL
CB
± INTRODUCTIONREPAIR INSTRUCTIONS
IN±5
5 Author: Date:
2001 PRIUS (RM778U)
(3) Precoated parts are indicated in the component il-
lustrations by the º
º symbol.
(g) When necessary, use a sealer on gaskets to prevent
leaks.
(h) Carefully observe all specifications for bolt tightening
torques. Always use a torque wrench.
(i) Use of special service tools (SST) and special service ma-
terials (SSM) may be required, depending on the nature
of the repair. Be sure to use SST and SSM where speci-
fied and follow the proper work procedure. A list of SST
and SSM can be found in Preparation section in this
manual.
(j) When replacing fuses, be sure the new fuse has the cor-
rect amperage rating. DO NOT exceed the rating or use
one with a lower rating.