2001 TOYOTA PRIUS display

BODY ELECTRICAL ± ACCESSORIES
182BE38
EMPS System
Abnormality WarningTHS Abnormality
Warning
HV Battery Warning
182BE39
178
3) Interrupt Screen
a. General
If an abnormal condition occurs in the ve-
hicle system, even if another screen is being
displayed, the interrupt screen automatically
indicates a warning to inform the driver of an
abnormality in the system. The warning in-
dication screen flashes for 5 seconds the
mark of the system in which the abnormality
occurred. Then, it illuminates and remains
displayed until the screen is switched or the
system is reinstated to normal.

List of Warning Display Items 
Warning Display ItemDescription of Warning
EMPS System
Abnormality WarningWhen an abnormality occurs in the EMPS (Electric Motor-assisted
Power Steering) system.
HV Battery Warning*When the HV battery voltage drops.
THS Abnormality
WarningWhen an abnormality occurs in the THS (TOYOTA Hybrid System).
*: While ªREADYº light is lighting.
b. HV Battery Warning
When starting THS (when turning the IG key to START position) and if HV battery is displayed in this
interrupt screen, it means that HV battery has abnormality.
4) On-screen
If the screen switches to another screen while
displaying a warning indication, the mark of
the system in which the abnormality occurred
is displayed at the top right area of the screen.
The displayed mark disappears when the sys-
tem is reinstated to normal.

BODY ELECTRICAL ± ACCESSORIES179
5. GPS (Global Positioning System) Voice Navigation
General
The GPS (Global Positioning System) function receives, via an GPS antenna, the signals that are trans-
mitted from the GPS satellites located in space at an approximate altitude of 20,000 km, in order to deter-
mine the vehicle's present position.
The GPS voice navigation function combines the radiowave navigation system that determines the pres-
ent position through the GPS signals, and the self-contained navigation system that detects the driven
distance and the direction of travel through the speed sensors and the gyro sensor that is contained in the
navigation ECU. The GPS voice navigation function is a high-precision navigation system that indicates
the vehicle position on the map display on the DVD and guides the route from the present position to the
destination on a map and pictogram and through voice instructions.
The multi-information display shows the data that has been calculated by the radiowave navigation sys-
tem and the self-contained navigation system.
Construction and Operation
The GPS voice navigation function consists of the following components:
GPS Antenna
Speed Sensor
GPS Receiver (contained in the navigation ECU)
Gyro Sensor (contained in the navigation ECU)
Navigation ECU
Speaker
For details on the basic operation of the GPS antenna and the navigation ECU, see page 175.
1) Speed Sensor
The navigation ECU will receive the vehicle speed signal directly from the meter ECU.
2) GPS Receiver
The GPS receiver demodulates the signals that are received by the GPS antenna from the satellites and
outputs them to the navigation ECU.

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.

B04748
B04749
1. +Terminal
2. +Terminal3. ±Terminal
4. ±Terminal
B04750
± INTRODUCTIONFOR ALL OF VEHICLES
IN±13
13 Author: Date:
2001 PRIUS (RM778U)
2. PRECAUTIONS TO BE OBSERVED WHEN INSPECT-
ING OR SERVICING ENGINE COMPARTMENT
The PRIUS, automatically turns the engine ON and OFF when
the ignition switch is set to the ON position provided that the
READY light on the instrument panel is it.
Before inspecting or servicing the engine compartment, there-
fore, remove the ignition switch key.
3. ACTIONS TO BE TAKEN WHEN BATTERIES ARE DE-
PLETED
(a) Actions to be taken when the auxiliary battery is depleted
HINT:
The following phenomena indicate that the auxiliary battery is
depleted:

No display appears on the instrument panel when you
turn the ignition switch to the ON position.

The hybrid system does not start.

The headlights are dark.

The sound from the horn is weak.
NOTICE:
Never use a quick charger.
(1) Move the shift lever to the P position, and engage
the parking brake.
(2) Remove the ignition key plate from the ignition
switch.
(3) Using a booster cable, connect the 12 V battery of
the rescue vehicle and auxiliary battery of the
stalled vehicle, as shown in the illustration.
(4) Start the engine of the rescue vehicle and run the
engine at a speed slightly higher than the idling
speed for 5 minutes to charge the auxiliary battery
of the stalled vehicle.
(5) Turn the ignition switch of the stalled vehicle to the
START position to start the hybrid system.
If the hybrid system fails to start and the master and HV battery
warning lights come on, the HV battery may have been dis-
charged.
(6) Disconnect the booster cable in the reverse way of
the connection procedure.
NOTICE:
If the auxiliary battery needs to be replaced, replace it only
with a 12 V battery specially designed for the use of the
PRIUS.

B04762
IN±14
± INTRODUCTIONFOR ALL OF VEHICLES
14 Author: Date:
2001 PRIUS (RM778U)
(b) Actions to be taken when HV battery is depleted
NOTICE:
Leaving a vehicle alone for 2 ± 3 months may cause electric
discharge from HV battery.
When this happens, replace the HV battery.
4. INSPECTION MODE
HINT:

The PRIUS automatically stops the engine while the ve-
hicle is stopped with the engine warmed up and battery
well charged if the A/C compressor operation is not re-
quired. Therefore, even if the vehicle stops for any reason
such as a check of ignition timing, the inspection mode
should be activated when continuous operation of the en-
gine is required.

The PRIUS has a skid control as traction control function.
When the wheel speed of the front wheels exceeds that
of the rear wheels, this function restrains the wheel speed
of the front wheels. It is necessary to activate the inspec-
tion mode and reset the skid control when turning only the
front wheels using a speedometer tester.
Activation inspection mode (Without using a hand±held tester)
(1) Perform the following (2) through (6) within 60 sec.
(2) Turn the ignition switch ON from OFF.
(3) With the shift lever in P position, fully depress the
accelerator pedal 2 times.
(4) With the shift lever in N position, fully depress the
accelerator pedal 2 times.
(5) With the shift lever in P position, fully depress the
accelerator pedal 2 times.
(6) Activate the inspecting mode and check that the hy-
brid system error warning light on the multi±center
display flashes.
(7) Turning the ignition switch to START starts the en-
gine's continuous operation.
NOTICE:

The idling speed in the inspection mode is approx.
1,000 rpm. The number of revolutions will increase up
to 1,500 rpm if the accelerator pedal is depressed to
a degree of less than 60%, and up to 2,250 rpm in a
case of 60% or more.

If a diagnosis code is recorded when entering the in-
spection mode, the master warning light and the error
warning light on the multi±center display is lit.

DIAGNOSTIC TROUBLE CODE CHECK PROCEDURE
Diagnostic Trouble
Code Check (Make a
note of and then clear)Confirmation
of SymptomsDiagnostic Trouble
Code CheckProblem Condition
Diagnostic Trouble
Code DisplayProblem symptoms
existSame diagnostic
trouble code is
displayedProblem is still occurring in the diagnostic
circuit
Normal code is
displayedThe problem is still occurring in a place
other than in the diagnostic circuit
(The diagnostic trouble code displayed
first is either for a past problem or it is a
secondary problem)
No problem
symptoms existThe problem occurred in the diagnostic
circuit in the past
Normal Code DisplayProblem symptoms
existNormal code is
displayedThe problem is still occurring in a place
other than in the diagnostic circuit
No problem
symptoms existNormal code is
displayedThe problem occurred in a place other
than in the diagnostic circuit in the past
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN±33
2001 PRIUS (RM778U)
In diagnostic trouble code check, it is very important to determine whether the problem indicated by the diag-
nostic trouble code is still occurring or occurred in the past but returned to normal at present. In addition,
it must be checked in the problem symptom check whether the malfunction indicated by the diagnostic
trouble code is directly related to the problem symptom or not. For this reason, the diagnostic trouble codes
should be checked before and after the symptom confirmation to determine the current conditions, as shown
in the table below. If this is not done, it may, depending on the case, result in unnecessary troubleshooting
for normally operating systems, thus making it more difficult to locate the problem, or in repairs not pertinent
to the problem. Therefore, always follow the procedure in correct order and perform the diagnostic trouble
code check.

Diagnostic trouble code check
Making a note of and clearing of the diagnostic trouble codes displayed
Symptom confirmation
No problem symptoms
exist Problem symptoms
exist
Simulation test using the symptom
simulation methods

Normal code displayed

Problem symptoms exist
Normal code displayed

No problem symptoms exist Diagnostic trouble code check
Troubleshooting of problem indicated
by diagnostic trouble code
Diagnostic trouble code displayed

Problem symptoms exist
System Normal Troubleshooting of each
problem symptom
If a diagnostic trouble code was
displayed in the initial diagnostic
trouble code check, it indicates
that the trouble may have occurred
in a wire harness or connector in
that circuit in the past. Therefore,
check the wire harness and con-
nectors (See page IN±41).
IN±34± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
2001 PRIUS (RM778U)
Taking into account the points on the previous page, a flow chart showing how to proceed with troubleshoot-
ing using the diagnostic trouble code check is shown below. This flow chart shows how to utilize the diagnos-
tic trouble code check effectively, then by carefully checking the results, indicates how to proceed either to
diagnostic trouble code troubleshooting or to troubleshooting of problem symptoms table.

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.