2001 TOYOTA PRIUS Service Repair Manual

BODY ELECTRICAL ± AIR CONDITIONING
182BE31
Tentative Damper Opening Angle
(During 2-Way Flow Mode)
Damper
Opening
Recirculation /
Fresh Air
SwitchingFresh
Air
2-Way
Flow
MAX HOT
182BE33
A / C SwitchMAX
Switch171
Air Inlet Control System
1) Manual Control
Drives the air inlet servomotor according to
the operation of the air inlet control switch and
fixes the dampers in the FRESH or RECIRC
position.
The 2-way flow mode control switches the re-
circulation / fresh-air function in accordance
with the opening of the air mix damper, calcu-
lates the target opening of the damper, and ro-
tates the servomotor.
2) Battery ECU Forced Fresh Air Mode
When the air conditioning ECU receives the forced fresh air mode signal from the battery ECU via the
HV ECU and the ECM, the damper forcefully switches to the FRESH mode.
3) DEF, FOOT / DEF Mode Control
When the mode switching switch is switched to FOOT / DEF mode from DEF mode or other than
FOOT / DEF mode, air conditioning ECU switches to FRESH mode forcibly.
Also, when the mode switching switch is switched to DEF mode from other than DEF mode, air condi-
tioning ECU turns MAX mode ON and switched to FRESH mode forcibly.
Compressor Control System
1) OFF Control
Turns OFF the magnetic clutch of the compressor when the conditions for turning the blower motor OFF
during warm-up control have been met.
2) Compressor Lock Judgment
When the magnetic clutch is ON, if the air
conditioning ECU judges that the compressor
has been locked, it turns OFF the magnetic
clutch relay and flashes the indicator lamp in
the A / C or MAX switch. The conditions in
which the ECU judges the compressor to have
locked are when a slippage rate of 80% or
more has been continued for 3 seconds or
more.

BODY ELECTRICAL ± AIR CONDITIONING 172
3) Refrigerant Pressure Malfunction Detection
By monitoring the pressure switch signal, this system can judge the refrigerant pressure to be abnormal,
and turns off the compressor magnetic clutch relay, if the pressure switch remains off.
4) MAX Switch ON Control
a. General
In case of usual air conditioning operation, the air conditioning system shows superior control on cool-
ing performance and fuel efficiency by combining the engine ON / OFF control by the hybrid control
and the air conditioning ON / OFF control.
In this MAX switch ON control, it controls by attaching greater importance to cooling performance of
the air conditioning.

BODY ELECTRICAL ± ACCESSORIES173
ACCESSORIES
MULTI-INFORMATION DISPLAY
1. General
A multi-information display has been provided on top of the center console as standard equipment.
Consisting of a 5.8-inch wide LCD (Liquid Crystal Display) screen, this multi-information display pro-
vides a vehicle information screen, warning screen, and an audio operation screen. The outside tempera-
ture is also shown on the screen.
A GPS (Global Positioning System) voice navigation is offered as an option. Through the use of the GPS
and the map data in a DVD (Digital Versatile Disc), this navigation system analyzes the position of the
vehicle and indicates that position on the map that is displayed on the screen. Additionally, it provides
voice instructions to guide the driver through the route to reach the destination that has been selected.
Listed below are the main functions of the multi-information display.
Function
Outline
Map Screen Display*
Enlargement / reduction, rotation and movement of map.
Indication of current position and direction of travel.
Correction of current position.
Setting, change and indication of route.
Voice guidance.
Indication of enlarged intersections.
Memory and indication of map position.
Audio Screen DisplayStatus of audio equipment and audio operation screen indication.
Information
Screen DisplayEnergy monitor screen indication.
Fuel consumption screen indication.
Adjustment
Screen DisplaySound quality adjustment screen indication.
Image quality adjustment screen indication.
No indication.
On-screen DisplayAudio status indication.
Warning indication.
Interrupt Screen
DisplayWarning indication.
Diagnosis Screen
DisplayDisplay system diagnosis.
Displays various type of coefficient settings.
*: with GPS Voice Navigation System

BODY ELECTRICAL ± ACCESSORIES
182BE34
Navigation
ECUGPS Antenna
AVC-LANBEAN
Gateway
ECUMeter
ECUECM
Center Cluster
Switches
 Navigation-related
 switches
 Audio-related
 switches
Display
ECU
Multi-information
DisplayAudio Unit Front LH
Speaker
(Voice
Guidance)
182BE35
GPS Antenna*
Navigation ECU*
DVD*
Center Cluster Switches
and Audio UnitMulti-information
Display 174
2. System Diagram
3. Layout of Components
*: with GPS Voice Navigation System

BODY ELECTRICAL ± ACCESSORIES175
4. Construction and Operation
General
This system mainly consists of a multi-information display, navigation ECU, display ECU, gateway ECU,
GPS antenna and audio unit.
The navigation ECU, display ECU, gateway ECU, and the audio unit all maintain communication through
the AVC-LAN.
Navigation ECU
The navigation ECU is provided on the models with the GPS voice navigation. Based on the map data on
the DVD, signals from the GPS satellites, signals from the built-in gyro sensor, and signals from the ve-
hicle's speed sensor, this ECU calculates the vehicle's present position, direction of travel, and driven dis-
tance, and transmits the data to the display ECU. In addition, it outputs navigation voice instructions.
Display ECU
Upon receiving the vehicle information that is transmitted by the gateway ECU, the navigation information
that is transmitted by the navigation ECU, and the operation information from the audio unit, the display
ECU displays these data on the multi-information display.
Gateway ECU
The gateway ECU transmits the vehicle information to the display ECU in order for it to be displayed on
multi-information display. Because vehicle information is transmitted by the ECUs that maintain commu-
nication on the BEAN (Body Electronics Area Network), the gateway ECU converts this information into
signals for AVC-LAN use and sends it to the display ECU.
GPS Antenna
The GPS antenna is provided on the models with the GPS voice navigation.
The GPS antenna receives signals from the GPS satellites that are located on the orbits that circle the earth
at an approximate altitude of 20,000 km. The GPS satellites continuously transmit orbit signals and the sig-
nal transmission time.
Multi-information Display
The multi-information display has the functions for displaying the map screen, audio screen, information
screen, adjustment screen, interrupt screen, and on-screen.
This system's self-diagnosis function can be displayed and operated on the multi-information display.
For details, refer to the 2001 Prius Repair Manual (Pub. No. RM778U).