Page 137 of 1111

BE±2
± BODY ELECTRICALBODY ELECTRICAL SYSTEM
2303 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
4. MICRO COMPUTER PRESET DRIVING POSITION SYSTEM
Power Seat Control System
Power Mirror Control System
Power Tilt and Telescopic Steering System
If the battery negative (±) terminal is disconnected, the preset driving positions stored in memory are erased,
so be sure to note the positions and reset them after the battery terminal is reconnected.
5. AUDIO SYSTEM
If the negative (±) terminal cable is disconnected from the battery, the preset AM, FM 1 and FM 2 sta-
tions stored in memory are erased, so be sure to note the stations and reset them after the negative
(±) terminal cable is reconnected to the battery.
If the negative (±) terminal cable is disconnected from the battery, the ºANTI±THEFT SYSTEMº will
operate when the cable is reconnected, but the radio, tape player and CD player will not operate. Be
sure to input the correct ID number so that the radio, tape player and CD player can be operated again.
6. MOBILE COMMUNICATION SYSTEM
If the vehicle is equipped with a mobile communication system, refer to precautions in the IN section.
Page 235 of 1111

BE0GC±05
BE±196
± BODY ELECTRICALAUDIO SYSTEM
2497 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
TROUBLESHOOTING
NOTICE:
When replacing the internal mechanism (computer part) of the audio system, be careful that no part
of your body or clothing comes in contact with the terminals of the leads from the IC, etc. of the re-
placement part (spare part).
HINT:
This inspection procedure is a simple troubleshooting which should be carried out on the vehicle during sys-
tem operation and was prepared on the assumption of system component troubles (except for the wires and
connectors, etc.).
Always inspect the trouble taking the following items into consideration.
Open or short circuit of the wire harness
Connector or terminal connection fault
For audio systems with anti±theft system, troubleshooting items marked ( * ) indicate that ºTrou-
bleshooting for ANTI±THEFT SYSTEMº should be carried out first.
ProblemNo.
RadioRadio not operating when power switch turned to 'ON'.1
Display indicates when power switch turned to 'ON', but no sound (including
'noise') is produced.2
Noise present, but AM ± FM not operating.3
Any speaker does not work.4
Any AM or FM does not work.5
Few preset turning bands.5
Reception poor.6
Sound quality poor.7
Preset memory disappears.8
Tape PlayerCassette tape cannot be inserted.9
Cassette tape inserted, but no power.10
Power coming in, but tape player not operating.11
Any speaker does not work.12
Sound quality poor.13
Tape jammed, malfunction with tape speed or auto±reverse.14
Cassette tape will not eject.15
CD PlayerCD cannot be inserted.16
CD inserted, but no power.17
Power coming in, but CD player not operating.18
Sound jumps.19
Sound quality poor (Volume faint).20
Any speaker does not work.21
CD will not be ejected.22
Power AmplifierNo power coming in.23
Power coming in, but power amplifier not operating.24
Any speaker does not work.25
NoiseNoise occurs26
Noise produced by vibration or shock while driving.27
Noise produced when engine starts.28
The term ºAMº includes LW,MW and SW, and the term ºFWº includes UKW.
Page 237 of 1111
1 Radio RADIO NOT OPERATING WHEN POWER SWITCH TURNED TO ºONº
+ B wire harness faulty.
GND faulty.
Power amplifier or ACC wire harness faulty.
Power amplifier or +B wire harness faulty.
GND faulty. Is tape player operating normally?
Check if RAD±No.2 fuse is OK?
Is power supplied to ACC terminal of power amplifier?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.
Check if GND (wire harness side) to radio assembly is OK?
Radio assembly faulty.
Replace fuse.
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 power amplifier
grounded normally? BE±198
± BODY ELECTRICALAUDIO SYSTEM
2499 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
Page 238 of 1111

2 RadioDISPLAY INDICATES WHEN POWER SWITCH TURNED TO
ºONº, BUT NO SOUND (INCLUDING ºNOISEº) IS PRODUCED
+ 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.
Does continuity exist 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 receiver?
Is power supplied to +B terminal of radio receiver?
Check if GND (wire harness side) of power amplifier
grounded normally?
± BODY ELECTRICALAUDIO SYSTEM
BE±199
2500 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
Page 239 of 1111
Speaker wire harness faulty. Is tape player operating normally?
Ye s
No
Radio assembly faulty.
Recheck system after repair. Radio assembly faulty.
Temporarily install another speaker? Functions OK?
Power amplifier faulty. Recheck system after repair.Speaker faulty. 4 Radio ANY SPEAKER DOSE NOT WORK
Is hiss noise produced by non±functioning speaker?
Does continuity exist in speaker wire harness?Ye s
Ye s No
Ye s
NoNo 3 Radio NOISE PRESENT, BUT AM±FM NOT OPERATING
Go to No.25
Radio faulty. If radio side faulty.
BE±200
± BODY ELECTRICALAUDIO SYSTEM
2501 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
Page 240 of 1111
5 RadioANY AM OR FM DOES NOR WORK
FEW PRESET TUNING BANDS
Problem with radio wave signals or location?
Are both AM and FM defective?Radio assembly faulty.
Go to No.16
Is tape player operating normally? Radio assembly faulty.
Is power for the antenna being output from the radio assembly?
Hiss noise from speaker? Temporarily install another speaker. Functions OK?
Radio assembly faulty. Recheck system after repair.Speaker faulty.
Power amplifier faulty.
Recheck system after repair. Poor signals, poor location.
No
Ye s
Ye s No
No
NoYe s
Ye s
Ye s
Ye s
No
No
± BODY ELECTRICALAUDIO SYSTEM
BE±201
2502 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
Page 242 of 1111

7 Radio SOUND QUALITY POOR
Ye sNo
Ye s
NG
OK Is sound quality always bad?
Is tape player operating normally?Poor signals, poor location.
Radio assembly faulty.
Install properly.
Speaker faulty. Is tape player operating normally?
Is speaker properly installed?
Radio assembly or power amplifier faulty.
Recheck system after repair. Temporarily install another speaker. Functions OK?Is sound quality bad in certain
areas only?
Radio assembly or power
amplifier faulty.
Can cassette tape be inserted in tape player?
Check if RADIO No.1 fuse is OK?Radio assembly faulty.
Replace fuse.
+B wire harness faulty.
GND faulty.
Power amplifier faulty. 8 Radio PRESET MEMORY DISAPPEARSNo
Radio assembly faulty.
No
NoNo NoYe s
Ye s
Ye s
Power amplifier faulty.
Radio assembly faulty.Ye s
Ye sYe s
No
No
No NG
NG
OKOKYe s
Check if GND (wire harness side) of power amplifier
grounded normally? Is power supplied to +B terminal of power amplifier?
Check if GND (wire harness side) of radio assembly
grounded normally? Is power supplied to +B terminal of radio assembly?
± BODY ELECTRICALAUDIO SYSTEM
BE±203
2504 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
Page 243 of 1111

9 Tape Player CASSETTE TAPE CANNOT BE INSERTED
Ye s
No NG Is there a foreign object inside tape player?
Is auto search button radio operating normally?
Check if RADIO No.1 fuse is OK?
Radio assembly faulty.Radio assembly faulty. Remove foreign object.
Replace fuse.
+B wire harness faulty.
GND faulty.
Power amplifier faulty.
Power amplifier faulty. Ye s No
No
OK
Ye s
OK
Ye s
OKNG
No
NG
10 Tape Player CASSETTE TAPE INSERTED, BUT NO POWER
Is radio operating normal?
Check if RAD No.2 fuse is OK?
ACC wire harness faulty.
Check if RADIO No.1 fuse is OK?Radio assembly faulty.
Replace fuse.
Replace fuse.
+B wire harness faulty.
Power amplifier faulty.
Radio assembly faulty.No
No
No
No OK
OKYe s
Ye s
Ye sYe s
NG
NG Check if GND (wire harness side) of power amplifier
grounded normally? Is power supplied to +B terminal of power amplifier?
Check if GND (wire harness side) of radio assembly
grounded normally? Is power supplied to +B terminal of radio assembly?
Is power supplied to +B terminal of radio assembly? Is power supplied to ACC terminal of power amplifier?
Is power supplied to ACC terminal of radio assembly? BE±204
± BODY ELECTRICALAUDIO SYSTEM
2505 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)