Lexus RX300 (MCU15). Manual - part 154

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 (Except Europe)

BE–163

LEXUS RX300   (RM785E)

6

Radio

POOR RECEPTION

Is the condition bad in comparison with other vehicles?

Are there any additional installation parts?
(Sun shade film, telephone antenna, etc.)

Check if there is any scratch and breaking of a wire on
the glass antenna and the defogger pattern.
(visual check. tester)
(See page BE–149)

Is the contact of the plug jack of the radio OK?

Does the condition get better by using the outer
antenna (such as pillar antenna)?

Is the contact of the antenna terminal on the glass
surface and the defogger terminal?

Is the continuity of the antenna cord OK?

Check the grounding of the antenna, antenna cord,
choke coil, and noise filter. (See page BE–149)

Does the condition get better by replacing
the choke coil?

Does the condition get better by replacing the
antenna cord?

Take a measure for contact.

An electric wave environment is bad.

Does the condition get better if
removing them?

Influence of additional installation parts.

Repair. (See page BE–79)

Check the radio.

Take a measure for contact.

Grounding failure.

Replace the antenna cord.

Replace the choke coil.

Replace the antenna cord.

Yes

No

Exchange the glass.

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

No

No

No

No

No

NG

OK

Yes

BE–164

–

BODY ELECTRICAL

AUDIO SYSTEM (Except Europe)

LEXUS RX300   (RM785E)

7

Radio

SOUND QUALITY POOR

Yes

No

Yes

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 DISAPPEARS

No

Radio assembly faulty.

No

No

No

No

Yes

Yes

Yes

Power amplifier faulty.

Radio assembly faulty.

Yes

Yes

Yes

No

No

No

NG

NG

OK

OK

Yes

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 ELECTRICAL

AUDIO SYSTEM (Except Europe)

BE–165

LEXUS RX300   (RM785E)

9

Tape Player

CASSETTE TAPE CANNOT BE INSERTED

Yes

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.

Yes

No

No

OK

Yes

OK

Yes

OK

NG

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

OK

Yes

Yes

Yes

Yes

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–166

–

BODY ELECTRICAL

AUDIO SYSTEM (Except Europe)

LEXUS RX300   (RM785E)