LEXUS LS430 2003 Factory Repair Manual

Fig. 62: Repairing Broken Wire
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SYSTEM CHART
System NameSee Procedure
Front Power Seat Control SystemINITIALIZATION

Fig. 1: Locating Audio System
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Fig. 2: Audio System Diagram
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Input and output signals of each ECU.
TRANSMITTING ECU (TRANSMITTER) CHART
1.CD (Compact Disc) player outline
a. A compact disc player uses a laser pickup to read digital signals recorded on a compact disc (CD).
Transmitting ECU
(Transmitter)
Receiving ECUSignalsCommunication method
Driver Side J/B ECUSteering Pad SwitchACC SW SignalBEAN (Column Bus)
Driver Side J/B ECUSteering Pad SwitchTaillight ON SignalBEAN (Column Bus)
Steering Pad SwitchRadio Receiver AssyAudio SignalBEAN (Column Bus) AVC-
LAN

By converting the digital signals to analog, it can play music and other things. In general, CD
players can play 4.7-inch (12 cm) or 3.2-inch (8 cm) disc.
HINT:
Do not disassemble any part of the CD player.
Do not apply oil to the CD player.
Do not insert anything but a CD into the CD player.
2.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. 3: Identifying AVC
-LAN Description
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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
systems. 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. If
the radio and navigation assy is equipped, it is the master unit.
The radio and navigation 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.
3.Communication system outline
a. Components of the audio system communicate with each other via the AVC-LAN.
b. The master component of the AVC-LAN is a radio receiver assy with a 60 to 80 ohms resistor. This
is essential for communication.
c. If a short circuit or open circuit occurs in the AVC-LAN circuit, communication is interrupted and
the audio system will stop functioning.
4.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.
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.
Pressing PWR switch does not turn on system (SEE PROBLEM SYMPTOMS TABLE
)
Other symptoms (go to step 3)
3.Check the diagnostic trouble codes (SEE SYSTEM CHECK MODE (DTC CHECK)
)
HINT:
If the audio system is equipped with a multi-display, check DTCs in the LEXUS NAVIGATION
SYSTEM section (SEE PRECAUTION
).

If the system cannot enter the diagnosis mode, inspect each AVC-LAN communication signal and
repair or replace problem parts (SEE AVC
-LAN CIRCUIT (STEREO COMPONENT
AMPLIFIER ASSY - STEREO COMPONENT TUNER) - AVC-LAN CIRCUIT (RADIO
RECEIVER ASSY - STEREO COMPONENT TUNER) ).
Even if the malfunction symptom is not confirmed, check the diagnostic trouble codes. This is
because the system stores past diagnostic trouble codes.
A code is output (go to step 4)
A code is not output (go to step 5)
4.(SEE DIAGNOSTIC TROUBLE CODE CHART
)
Find the output code on the diagnostic trouble code chart.
Output the diagnostic trouble code (go to step 7)
5.(SEE PROBLEM SYMPTOMS TABLE
)
Find the applicable symptom code in the problem symptoms table.
HINT:
If the symptom does not recur and no code is output, perform the symptom reproduction method (SEE
HOW TO PROCEED WITH TROUBLESHOOTING
).
There is an applicable symptom code in the table (go to step 7)
There is no applicable symptom code in the table (go to step 6)
6.Check the ECU terminal arrangement based on the malfunction symptom (SEE TERMINALS OF
ECU )
7.Check the circuit
Adjust, repair or replace as necessary.
8.Recheck the diagnostic trouble code (SEE SYSTEM CHECK MODE (DTC CLEAR/RECHECK)
)
HINT:
After deleting the DTC, recheck the diagnostic trouble code.
9.Perform confirmation test
END

Fig. 4: Customer Problem Analysis Check Sheet
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1.Radio Description
a. Radio frequency band
1. Radio Broadcasts use the radio frequency bands shown in the table below.
Fig. 5: Radio Frequency Band Chart

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LF: Low Frequency
MF: Medium Frequency
HF: High Frequency
VHF: Very High Frequency
b. Service area
1. The service areas of the AM and FM broadcasts are vastly different. Even if an AM
broadcast has clear reception, an FM broadcast originating in the same location may not be
received at all.
The service area of FM stereo broadcasts is small, and static as well as interference (noise) easily
enter the si
gnal.

Fig. 6: Identifying Service Area
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2. Radio reception problems
HINT:
In addition to static, other problems such as "phasing", "multi-path", and "fade out" exist. These problems
are not caused by electrical noise, but by the radio signal propagation method itself.
1. Phasing
The AM frequency band reflects off the earth's ionosphere at night. When this occurs, the reflected
signal may interfere with the direct signal sent by the same transmitter. This phenomenon is known
as "Phasing".