LEXUS LS430 2003 Factory Repair Manual

Fig. 2: Lexus Navigation System Diagram (1 Of 2)
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Fig. 3: Lexus Navigation System Diagram (2 Of 2)

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1.Navigation system outline
a. Vehicle position tracking methods
It is essential that the navigation system correctly tracks the current vehicle position and displays it
on the map. There are 2 methods to track the current vehicle position: autonomous (dead
reckoning) and GPS* (satellite) navigation. Both navigation methods are used in conjunction with
each other.
* GPS (Global Positionin
g System)

Fig. 4: Identifying Navigation System Outline
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OPERATION DESCRIPTION CHART
OperationDescription
Vehicle Position
CalculationThe navigation ECU calculates the current vehicle position (direction
and current position) using the direction deviation signal from the gyro
sensor and the running distance signal from the vehicle speed sensor and
creates the driving route.
Map Display processingThe navigation ECU displays the vehicle track on the map by processing
the vehicle position data, vehicle running track, and map data from the

HINT:
The combination of autonomous and GPS navigation makes it possible to display the vehicle
position even when the vehicle is in places where the GPS radio wave cannot receive a signal.
<003a004b00480051000300520051004f005c000300440058005700520051005200500052005800560003005100440059004c004a00440057004c005200510003004c005600030058005600480047000f0003004b0052005a0048005900480055000f000300
57004b004800030050004400530053004c0051004a00030044[ccuracy may slightly decline.
Fig. 5: Identifying GPS Satellite

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b. Autonomous navigation
This method determines the relative vehicle position based on the running track determined by the
gyro and vehicle speed sensors located in the navigation ECU.
1. Gyro sensor
Calculates the direction b
y detecting angular velocity. It is located in the radio and navigation
map disc.
Map MatchingThe map data from the map disc is compared to the vehicle position and
running track data. Then, the vehicle position is matched with the
nearest road.
GPS CorrectionThe vehicle position is matched to the position measured by GPS. Then,
the measurement position data from the GPS unit is compared with the
vehicle position and running track data. If the position is widely
different, the GPS measurement position is used.
Distance CorrectionThe running distance signal from the vehicle speed sensor includes the
error caused by tire wear and slippage between the tires and road
surface. Distance correction is performed to account for this. The
navigation ECU automatically offsets the running distance signal to
make up for the difference between it and the distance data of the map.
The offset is automatically updated.

assy.
2. Vehicle speed sensor
Used to calculate the vehicle running distance.
c. GPS navigation (Satellite navigation)
This method detects the absolute vehicle position using radio wave from a GPS satellite.
* GPS satellites were launched by the U.S. Department of Defence for military purposes.
Fig. 6: Identifying Autonomous Navigation

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NUMBER OF SATELLITES CHART
d. Map matchin
g
Number of
satellitesMeasurementDescription
2 or lessMeasurement
impossibleVehicle position cannot be obtained because the number of
satellites is not enough.
32-dimensional
measurement is possibleVehicle position is obtained based on the current longitude
and latitude. (This is less precise than 3-dimensional
measurement)
43-dimensional
measurement is possibleVehicle position is obtained based on the current
longitude, latitude and altitude.

The current driving route is calculated by autonomous navigation (according to the gyro sensor and
vehicle speed sensor) and GPS navigation. This information is then compared with possible road
shapes from the map data in the map disc and the vehicle position is set onto the most appropriate
road.
Fig. 7: Identifying Map Matching

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2.DVD (Digital Versatile Disc) player outline (for navigation map)
a. The navigation ECU uses a laser pickup to read the digital signals recorded on a DVD.
HINT:
Do not disassemble any part of the navigation ECU.
Do not apply oil to the navigation ECU.
Do not insert anything but a DVD into the navigation ECU.
3.Multi-display outline
a. Touch switch
Touch switches are touch-sensitive (interactive) switches operated by touching the screen. When a
switch is pressed, the outer glass bends in to contact the inner glass at the pressed position. By
doing this, the voltage ratio is measured and the pressed position is detected.

Fig. 8: Identifying Multi-Display Outline
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4.AVC-LAN Description
a. What is AVC-LAN?
AVC-LAN, an abbreviation for "Audio Visual Communication Local Area Network", is a united
standard developed by the manufacturers in affiliation with Toyota Motor Corporation. This
standard pertains to audio and visual signals as well as switch and communication signals.
Fig. 9: Identifying Avc
-Lan System
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b. Purpose:
Recently, car audio systems have rapidly developed and the functions vastly changed. The
conventional car audio system is being integrated with multi-media interfaces similar to those in
navigation systems. At the same time, customers are demanding higher quality from their audio
s
ystems. This is merely an overview of the standardization background. The specific purposes are

as follows.
1. To solve sound problems, etc. caused by using components of different manufacturers
through signal standardization.
2. To allow each manufacturer to concentrate on developing products they do best. From this,
reasonably priced products can be produced.
HINT:
If a +B or GND short is detected in the AVC-LAN circuit, communication is interrupted and
the audio system will stop functioning.
If an audio system is equipped with a navigation system, the multi-display unit acts as the
master unit.
If the navigation system is not equipped, the audio head unit acts as the master unit instead. I
f
the radio and navigation assy is equipped, it is the master unit.
The radio receiver assy provides resistance to make communication possible.
The car audio system with an AVC-LAN circuit has a diagnostic function.
Each component has a specified number (3-digit) called a physical address. Each function
has a number (2-digit) called a logical address.
5.Communication system outline
a. Components of the navigation system communicate with each other via the AVC-LAN.
b. Radio receiver assy has enough resistance (60 to 80 ohms) necessary for transmitting the
communication. This is essential for communication.
c. If a short circuit or open circuit occurs in the AVC-LAN circuit, communication is interrupted and
the navigation system will stop functioning.
6.Diagnostic function outline
a. The audio system has a diagnostic function (the result is indicated on the master unit).
b. A 3-digit hexadecimal component code (physical address) is allocated to each component on the
AVC-LAN. Using this code, the component in the diagnostic function can be displayed.
7.Bluetooth outline
a. BLUETOOTH is a new wireless connection technology that uses the 2.4 GHz frequency band. This
makes it possible to connect a cellular phone (BLUETOOTH capable phone*1) to the multi-display
(BLUETOOTH system is built in), and use a hands-free function with the cellular phone in a
pocket or bag. As a result, it is not necessary to use a connector for the cellular phone.
*1: Some versions of BLUETOOTH capable cellular phone may not function.
HINT:
The communication performance of BLUETOOTH may vary depending on obstructions or radio
wave conditions between communication devices, electromagnetic radiation, communication
device sensitivit
y, or antenna capacity.

Fig. 10: Identifying Bluetooth Capable Cellular
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1.Vehicle brought into a workshop
2.Diagnostic questioning and symptom confirmation (see CUSTOMER PROBLEM ANALYSIS
CHECK )
Ask the customer about symptoms and confirm malfunctions. Fill out the Customer Problem Analysis
check sheet.
The screen displays nothing (go to step 6, proceed to "BLACK SCREEN (NO IMAGE APPEARS
ON NAVIGATION/AUDIO SCREEN)")
Other symptoms (go to step 3)
3.Confirm the system normal condition (see SYSTEM NORMAL CONDITION CHECK
)
Applicable (This is not a malfunction.)
Not applicable (go to step 4)
4.Check the diagnostic trouble codes (see DIAGNOSTIC TROUBLE CODE CHART
)
HINT:
If the system cannot enter the diagnosis mode, inspect each AVC-LAN communication signal and