service TOYOTA PRIUS 2001 Service Workshop Manual

CHASSIS ± P111 HYBRID TRANSAXLE
182CH25
182CH26Shift Position
Sensor
Shift
Position
SensorMain
Sub
HV
ECU
Serial Data
LinkEngine
ECUCombination
Meter
Voltage
: Defined
: Region
Voltage
Signal
Stroke B
D
N
R
P
PRNDBSwitch
Signal
Service Tip
Because it is extremely difficult to precisely assemble the shift position sensors, do not disassemble the
shift lever. 88

SHIFT CONTROL
1. Shift Lever
A column-type shift lever with 5 positions has been adopted. The shift lever is operated by moving it in the
vehicle's longitudinal direction to ensure excellent ease of use. The shift lever is integrated with the shift posi-
tion sensor.
2. Shift Control
For shift control, a shift-by-wire system has been
adopted. This system uses electrical signals that
are output by the shift position sensor to determine
the shift position. For operating the parking lock
pawl in the transaxle, however, a shift cable is used
for attaining P position.
The shift position sensor outputs two systems of
signals: the main switch signals, and the sub
switch signals containing high and low voltages.
When these signals match, the HV ECU deter-
mines the respective shift position.

CHASSIS ± STEERING
182CH68
Rear Wheel
Speed SensorsBrake ECU
Torque Sensor Signal 1
Torque Sensor Signal 2
EMPS
ECUMeter ECU
Gateway ECUDLC3
Display ECU
Multi-information
Display
123
EMPS (Electric Motor-assisted Power Steering)
1. General
In accordance with sensor information such as that provided by the rear wheel speed sensors, the torque sen-
sor that is mounted on the steering gear, and the EMPS ECU determines the direction and the force of the
power assist and actuates the DC motor that is mounted on the steering gear to provide power assist to the
steering effort.
The EMPS in the Prius the following features:
This system can provide power assist even when the engine is stopped.
This system offers excellent fuel economy characteristics because power assist is provided by the DC mo-
tor that is mounted on the steering gear, and this motor consumes energy only when power assist is re-
quired.
Unlike the conventional hydraulic power steering system, this system excels in serviceability because it
does not require pipes or the power steering fluid.

System Diagram 

BODY ELECTRICAL ± METER
182BE08
Flashes when the
ignition switch is
turned to START
Illuminates when
the vehicle is ready
to be driven
Service Tip

Inverter unit cover is left open.

HV ECU has detected a collision.149
ªREADYº Light
When the shift position is P, turning the ignition
switch to START causes the ªREADYº light to
flash and enables the vehicle to be driven. Then,
this indicator illuminates and the buzzer sounds
simultaneously.
If the indicator does not illuminate, the vehicle cannot be driven because one of the driving prohibition
conditions listed below applies.

Service plug disconnected.

Hybrid system abnormality.

Driving prohibition condition due to overload
on MG1, MG2 or inverter.
Master Warning Light
A master warning light that informs the driver if an abnormality occurs in either the EMPS, HV batteries,
or the THS has been adopted.
If an abnormality occurs in the system, the master warning light illuminates and the multi-information dis-
play shows the warning items. For details, see page 178.
Output Control Warning Light
An output control warning light has been adopted to show the drop of power function due to the output drop
of HV batteries.
This warning light comes on when the temperature of HV batteries is higher or lower than that of specified
range, or when SOC (State of Charge) is lower than the specified value with the shift position in R range.
When this warning light comes on, avoid sudden acceleration and drive carefully.

BODY ELECTRICAL ± AIR CONDITIONING
165BE24
Condenser and Modulator
Scroll Compressor
with Oil Separator
Separator
Compressor Refrigerant Gas +
Compressor Oil
Compressor Oil
Evaporator Expansion
Valve 162
Oil Separator
1) General
A CS (Centrifugal with Shutter) type oil separator has been adopted to reduce the circulation rate of the
compressor oil that is intermixed with the refrigerant and circulates in the refrigeration cycle.
This oil separator is provided with a cylindrical pipe in the separator case, enabling the refrigerant gas
that has been discharged through the discharge gas inlet to be separated into refrigerant gas and oil
through centrifugal force, and minimizing the outflow of the oil to the discharge service port. As a result,
the oil circulation rate has been reduced and makes energy savings possible.

BODY ELECTRICAL ± AIR CONDITIONING
165BE26165BE25
Discharge Port
Discharge Service Port
Pipe
Oil Discharge Hole
Shutter
Oil Storage Chamber
Discharge ValveRefrigerant and
Compressor OilRefrigerant
Compressor
Oil
182BE20182BE19
Flow of Coolant
Bypass Valve
Water Pump OFF
(Engine ON)Bypass Valve
Water Pump ON
(Engine OFF)Flow of Coolant163
2) Construction and Operation
The refrigerant gas that is discharged from the discharge port flows by rotating around the cylindrical
pipe in the oil separator. At this time, the centrifugal force that is created during the rotation separates
the refrigerant gas and the compressor oil due to the difference in their specific gravity. The refrigerant
gas with the lighter specific gravity passes through the inside of the pipe and travels from the discharge
service port to the outside of the compressor. The compressor oil with the heavier specific gravity is dis-
charged through the oil discharge hole in the shutter and is stored in the oil storage chamber. Then, the
compressor oil is fed again into the compressor and circulates inside the compressor.
4. Water Pump (For Air Conditioning)
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 has been adopted.
When the engine is running, this water pump ceases its operation and opens the bypass valve to minimize
the flow resistance of the coolant that is pumped by the engine water pump.

BODY ELECTRICAL ± AIR CONDITIONING
182BE21
One Touch Clip
Glove Compartment Door
Stopper PinClean Air Filter
Service Tip
The replacement interval for the clean air filter is 30,000 km or 2 years.
However, it varies with the use conditions (or environment). 164
5. Clean Air Filter
A clean air filter that excels in removing pollen and dust is standard equipment.
This filter, which cleans the air in the cabin, is made of polyester. Thus, it can be disposed of easily as a com-
bustible material, a feature that is provided in consideration of the environment.
To facilitate the replacement of the filter, a one-touch clip is used in the filter cover which is unified with filter
case. Thus, a construction that excels in serviceability has been realized.

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.

IN0HO±01
B04757
B04746
IN±10
± INTRODUCTIONFOR ALL OF VEHICLES
10 Author: Date:
2001 PRIUS (RM778U)
FOR ALL OF VEHICLES
PRECAUTION
1. PRECAUTIONS FOR HIGH±VOLTAGE CIRCUIT IN-
SPECTION AND SERVICE
(a) Engineers to be engaged in inspection and servicing re-
lated to high±voltage systems should undergo special
training.
(b) All the high±voltage wire harness connectors are colored
orange: the HV battery and other high±voltage compo-
nents are identified by the ºHigh Voltageº caution labels.
Do not carelessly touch these wires and components.
(c) Before inspecting or servicing the high±voltage system,
be sure to take measures such as wearing insulated
gloves and removing the service plug to prevent electro-
cution. Carry the removed service plug in your pocket to
prevent other technicians from reinstalling it while you are
servicing the vehicle.
(d) After removing the service plug, wait 5 minutes before
touching any of the high±voltage connectors and termi-
nals.
HINT:
The 5 minutes are required to discharge the high±voltage con-
denser inside the inverter.
(e) Before wearing insulated gloves, make sure that they are
not cracked, reptured, torn, or damaged in any other way.
Do not wear wet insulated gloves.
(f) When servicing the vehicle, do not wear a metal object
like a mechanical pencil or scale that may drop acciden-
tally and cause a short circuit.
(g) Before touching a bare high±voltage terminal, wear insu-
lated gloves and ensure that the terminal is not charged
with electricity (approx. 0 V) using an electrical tester.