Lexus GS300/400 (2000 year). Service manual - part 60

1

Radio

RADIO NOT OPERATING WHEN POWER SWITCH TURNED TO ”ON”

+ 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?

Yes

NG

No

OK

No

No

No

No

OK

OK

OK

Yes

Yes

Yes

Yes

NG

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 ELECTRICAL

AUDIO SYSTEM

2499

2

Radio

DISPLAY INDICATES WHEN POWER SWITCH TURNED TO
”ON”, BUT NO SOUND (INCLUDING ”NOISE”) 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?

Yes

NG

No

OK

No

No

No

No

OK

OK

OK

Yes

Yes

Yes

Yes

NG

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?

Yes

Yes

No

No

No

Yes

Power 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 ELECTRICAL

AUDIO SYSTEM

BE–199

2500

Speaker wire harness faulty.

Is tape player operating normally?

Yes

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?

Yes

Yes

No

Yes

No

No

3

Radio

NOISE PRESENT, BUT AM–FM NOT OPERATING

Go to No.25

Radio faulty.

If radio side faulty.

BE–200

–

BODY ELECTRICAL

AUDIO SYSTEM

2501

5

Radio

ANY 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

Yes

Yes

No

No

No

Yes

Yes

Yes

Yes

No

No

–

BODY ELECTRICAL

AUDIO SYSTEM

BE–201

2502