audio LEXUS GS400 2000 Service Owner's Manual

CD Player SOUND JUMPS
19
CD player faulty. Does sound jump only during strong vibration?
Is CD player properly installed?
Functions OK if different CD inserted?
Has sudden temperature change occurred inside cabin?Jumping caused by vibration.
Install properly.
CD faulty.
Formation of condensation due to
temp. changes. Ye sYe s
Ye s
Ye s No No
No
No
20 CD Player SOUND QUALITY POOR (VOLUME FAINT)
Is radio operating normally?CD faulty. Function OK if different CD inserted?
Speaker faulty. Temporarily install another speaker.
Functions OK?Ye s
No
Is speaker property installed?CD player faulty.
Install properly. Ye s
Ye s Ye s No
NoNo
Radio assembly or CD player or power amplifier faulty.
± BODY ELECTRICALAUDIO SYSTEM
BE±209
2510 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)

CD player faulty.
Power amplifier faulty.
Recheck system after repair. Temporarily install another speaker.
Function OK?21 CD Player ANY SPEAKER DOES NOT WORK
Speaker wire harness faulty.
Speaker faulty. Is hiss noise produced by non±functioning speaker?
Does continuity exist in speaker wire harness? Is radio operating normally?
Ye sYe s
Ye s
Ye s No
No
NoNoRadio assembly faulty.
Recheck system after repair.
CD player faulty. 22 CD Player CD WILL NOT BE EJECTED
Is auto search button of radio
operating normally?
NoRadio assembly
faulty.
Replace fuse.
+B wire harness faulty.
Power amplifier faulty.
Radio assembly faulty. Check if RADIO No.1 fuse is OK?No
No
No Ye s
NG
OK
Ye s
Ye sYe s
Is power supplied to +B terminal of power amplifier?
Is power supplied to +B terminal of radio receiver?Is power supplied to +B terminal
of CD player? BE±210
± BODY ELECTRICALAUDIO SYSTEM
2511 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)

23 Power Amplifier NO POWER COMING IN
+ B wire harness faulty.
GND faulty.
Power amplifier or wire harness faulty.
Power amplifier or wire harness faulty.
GND faulty. Is tape player operating normally?
Check if RAD±No.2 fuse is OK?Ye s
NG
No OK No
No
No
No OK
OK
OK Ye s
Ye s
Ye s
Ye sNG
NG
NG Check if RAD±No.1 fuse is OK?
Radio assembly faulty.Replace fuse.
ACC wire harness faulty. Radio assembly faulty.
Replace fuse.
Check if GND (wire harness side) of power amplifier
grounded normally?Is power supplied to ACC terminal of power amplifier?
Is power supplied to +B terminal of power amplifier?
Is power supplied to ACC terminal of radio assembly?
Is power supplied to +B terminal of radio assembly?
Check if GND (wire harness side) of radio assembly
grounded normally?
± BODY ELECTRICALAUDIO SYSTEM
BE±211
2512 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)

24 Power AmplifierPOWER COMIMG IN, BUT WOOFER (POWER) AMPLIFIER NOT
OPERATING
+ B wire harness faulty.
GND faulty.
Power amplifier faulty.
Speaker wire harness faulty. GND faulty. Is tape player operating normally?
Check if RAD±No.2 fuse is OK?Ye s
NG
No OK No
No
No
No OK
OK
OK Ye s
Ye s
Ye s
Ye sNG
NG
NG Check if RAD±No.1 fuse is OK?
Radio assembly faulty. Recheck system after repair.Replace fuse.
ACC wire harness faulty. Radio assembly faulty.
Replace fuse.
Is there continuity in speaker wire harness?
Temporarily install another speaker. Functions OK?
Hiss noise from speaker?Ye s
Ye s NoNo
No Ye sPower amplifier faulty.
Power amplifier faulty.
Recheck system after repair. Speaker faulty.
Is power supplied to ACC terminal of power amplifier?
Check if GND (wire harness side) of power amplifier
grounded normally? Is power supplied to +B terminal of power amplifier?
Is power supplied to ACC terminal of radio assembly?
Is power supplied to +B terminal of radio assembly?
Check if GND (wire harness side) of radio assembly
grounded normally? BE±212
± BODY ELECTRICALAUDIO SYSTEM
2513 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)

CD player faulty.
Power amplifier faulty.
Recheck system after repair. Temporarily install another speaker.
Function OK?25 Power Amplifier ANY SPEAKER DOES NOT WORK
Speaker wire harness faulty.
Speaker faulty. Is hiss noise produced by non±functioning speaker?
Does continuity exist in speaker wire harness? Is radio operating normally?
Ye sYe s
Ye s
Ye s No
No
NoNoRadio assembly faulty.
Recheck system after repair.
± BODY ELECTRICALAUDIO SYSTEM
BE±213
2514 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)

26 Noise NOISE OCCURS
No
Ye s
NG
OK Does the noise occur only in the radio?
Does the noise occur in a particular place?
Is there any additional installation part
around the glass imprinted antenna?
(Sun shade film, telephone antenna etc.)
Does the noise occur even pulling out the
antenna cord from the radio?
Does the noise occur even after pulling out the
antenna terminal on the glass surface?
Isn't there any adhesive (Butyl rubber)
stuck on the bases of the antenna
terminal, defogger terminal and bus bar?
Check the grounding of the antenna,
antenna cord, coke coil, and noise filter.
(See page BE±190) Does the noise occur even after pulling out
the defogger terminal?
Does the condition get better by replacing
the antenna cord.
Noise rediates directly to the antenna from the
generation source. Does the condition get better by replacing
the choke coil?
Replace the antenna cord. Replace the choke coil. Interfering noise from the defogger line
and choke coil.
Grounding failure. Failure of glass installation.
Must plane the butyl rubber. Noise mixing into the antenna cable. Check the radio. Influence of the film or the noise radiation
of the additional installation part. Does the noise stop by removing it? An electric environment.Refer to No.27. (It occurs in the cassette and CD.)
Ye s
Ye s
Ye s
Ye s
Ye s
Ye s
Ye s
Ye s No
No
No
No
No
No
No
No
BE±214
± BODY ELECTRICALAUDIO SYSTEM
2515 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)

27 Noise NOISE PRODUCED BY VIBRATION OR SHOCK WHILE DRIVING
No
Ye s Is speaker properly installed?
Noise is produced from static eletricity accumulating in the vehicle body. With vehicles stationary lightly tap each system.
Is noise produced?Install properly.
Each system faulty. Is speaker properly installed?
No
No Ye s
Ye s
28 Noise NOISE PRODUCED WHEN ENGINE STARTS
NoYe s Whistling noise which becomes high±pitched when
accelerator strongly depressed, disappears shortly
after engine stops.Generator noise.
A/C noise.
Fuel gauge noise.
Horn noise.
Ignition noise.
Turn signal noise.
Washer noise.
Engine coolant temp. gauge noise.
Wiper noise. Whining noise occurs when A/C is operating.
Scratching noise occurs during sudden acceleration, driving on rough
roads or when ignition switch is turned ON.
Clicking sound is heard when horn button is pressed, then
released. Whirring/grating sound is heard when pushed
continuously.
Murmuring sound stops when engine stops.
Tick±tack noise occurs in co±ordination with blinking
offlasher.
Noise occurs during window washer operation.
Scratching noise occurs while engine is running,
and continues a while even after engine stops.
Scraping noise in line with wiper beat.
Other type of noiseYe s
Ye s
Ye s
Ye s
Ye s
Ye s
Ye s
Ye s No
No
No
No
No
No
No
No
± BODY ELECTRICALAUDIO SYSTEM
BE±215
2516 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)

BE0GD±10
I01372
Ignition SwitchRadio Assembly Tweeter
Front Speakers
Rear Speakers
Tweeter
Radio Assembly LEXUS Navigatioin
System Woofer
Power Amplifier
(NAKAMICHI made)
Driver Side Junction Block

RAD NO.2 FuseEngine Room No.1
Junction Block

ECU±B1 Fuse

RAD NO.1 Fuse
Passenger Side
Junction Block

DOME Fuse CD Auto ChangerCD Magazine
Power Amplifier
(PIONEER made)
BE±216
± BODY ELECTRICALAUDIO SYSTEM
2517 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
LOCATION
The vehicle shown in this illustration is ºGS400º.
All components of ºGS300º other than the ones used for engine are same as ºGS400º.

BE0GE±03
I04310
Wire Harness Side
I04189
Wire Harness Side
Connector ºBº
Connector ºDº Connector ºCº Connector ºAº
± BODY ELECTRICALAUDIO SYSTEM
BE±217
2518 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
1. Except NAKAMICHI made:
INSPECT CD AUTO CHANGER CIRCUIT
Disconnect connectors from CD auto changer and inspect the
connector on the wire harness side.
Tester connectionConditionSpecified condition
8 ± GroundConstantContinuity
5 ± GroundConstantBattery positive voltage
10 ± GroundIgnition switch LOCKNo voltage
10 ± GroundIgnition switch ACC or ONBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.
HINT:

Check the wire harness between the radio receiver as-
sembly and the CD auto changer.

Since the signals to and from the MUTE, R±, R+, L±, L+,
TX
± and TX+ terminals are serial signals, they cannot or-
dinarily be measured with a tester.
2. Except NAKAMICHI made:
INSPECT POWER AMPLIFIER CIRCUIT
Disconnect the connector from power amplifier and inspect the
connector on the wire harness side.
Tester connectionConditionSpecified condition
B7 ± GroundConstantContinuity
C12 ± GroundIgnition switch LOCK and radio switch ONNo voltage
C12 ± GroundIgnition switch ACC or ON and radio switch ONBattery positive voltage
B4 ± GroundConstantBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.

I04190
Wire Harness Side
Connector ºAº Connector ºBº BE±218
± BODY ELECTRICALAUDIO SYSTEM
2519 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
3. Except NAKAMICHI made:
INSPECT RADIO RECEIVER ASSEMBLY CIRCUIT
Disconnect the connectors from the radio receiver assembly,
and inspect the connector on the wire harness side.
Tester connectionConditionSpecified condition
A2 ± GroundConstantContinuity
A4 ± GroundConstantBattery positive voltage
A1 ± GroundIgnition switch LOCKNo voltage
A1 ± GroundIgnition switch ACC or ONBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.
HINT:
Check the wire harness between radio receiver assembly and
the CD auto changer, between radio receiver assembly and
power amplifier.