Page 233 of 1807
1 Radio RADIO NOT OPERATING WHEN POWER SWITCH TURNED TO ºONº
+ B wire harness faulty.
GND faulty.
Power amplifier or wire harness faulty.
Power amplifier or wire harness faulty.
GND faulty.
Check if GND (wire harness side) to power amplifier is OK?
Is tape player operating normally?
Check if RAD-No.2 fuse is OK?
Is ACC applied to power amplifier?
Is + B applied to 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?
Is + B applied to radio assembly?
Radio assembly faulty.Replace fuse.
ACC wire harness faulty.
Is ACC applied to radio assembly?
Check if GND (wire harness side) to radio assembly is OK?
Radio assembly faulty.
Replace fuse.
- BODY ELECTRICALAUDIO SYSTEM
BE-77
2055 Author: Date:
1997 SUPRA (RM502U)
Page 234 of 1807

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.
Check if GND (wire harness side) to power amplifier is OK?
Is tape player operating normally?
Check if RAD-No.2 fuse is OK?
Is ACC applied to power amplifier?
Is + B applied to 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?
Is + B applied to radio assembly?
Radio assembly faulty. Recheck system after repair.Replace fuse.
ACC wire harness faulty.
Is ACC applied to radio assembly?
Check if GND (wire harness side) to radio assembly is OK?
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.
BE-78
- BODY ELECTRICALAUDIO SYSTEM
2056 Author: Date:
1997 SUPRA (RM502U)
Page 235 of 1807
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?
Is there continuity 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.
- BODY ELECTRICALAUDIO SYSTEM
BE-79
2057 Author: Date:
1997 SUPRA (RM502U)
Page 236 of 1807
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 BE-80
- BODY ELECTRICALAUDIO SYSTEM
2058 Author: Date:
1997 SUPRA (RM502U)
Page 237 of 1807

6
Radio
POOR RECEPTION
Is the condition bad in comparison with other vehicle?
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-56)
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-72)
Does the condition get better by exchanging
the choke coil?
Does the condition get better by exchanging the
antenna cord?Take a measure for contact. An electric wave environment.
Does the condition get better if removing
them?
Influence of additional installation parts.
Influence of the sun shade film.
Repair. (See page BE-56)
Check the radio.
Take a measure for contact.
Grounding failure. Exchange the antenna cord.
Exchange the choke coil.
Exchange the antenna cord. Ye s
No
Exchange the glass.Ye s
Ye s
Ye s
Ye s
Ye s
Ye s
Ye s
Ye s No
No
No
NoNo
No
No
No
NG
OK
- BODY ELECTRICALAUDIO SYSTEM
BE-81
2059 Author: Date:
1997 SUPRA (RM502U)
Page 238 of 1807

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?
Is +B applied to power amplifier?
Check if GND (wire harness side) to power amplifier?
Is +B applied to radio assembly?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. Check if GND (wire harness side) to radio assembly?
Radio assembly faulty.Ye s
Ye sYe s
No
No
No NG
NG
OKOKYe s
BE-82
- BODY ELECTRICALAUDIO SYSTEM
2060 Author: Date:
1997 SUPRA (RM502U)
Page 239 of 1807

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?
Is +B applied to power amplifier?
Check if GND (wire harness side) to power amplifier is OK?
Is +B applied to radio assembly?
Check if GND (wire harness side) to radio assembly 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
Is ACC applied to radio assembly? 10 Tape Player CASSETTE TAPE INSERTED, BUT NO POWER
Is radio operating normal?
Check if RAD No.2 fuse is OK?
Is ACC applied to power amplifier?
Is +B applied to power amplifier?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
- BODY ELECTRICALAUDIO SYSTEM
BE-83
2061 Author: Date:
1997 SUPRA (RM502U)
Page 240 of 1807
11 Tape Player POWER COMING IN, BUT TAPE PLAYER NOT OPERATING
Ye s
NoRadio assembly faulty. Cassette tape faulty.
Speaker wire harness faulty.
Speaker faulty.
Power amplifier faulty.
Recheck system after repair. Ye s No
No
Ye s
Ye sNo No Function OK if different cassette tape inserted?
Is radio operating normally?
Is there continuity in speaker wire harness?
Temporarily install another speaker.
Function OK?
Hiss noise from speaker?
Radio assembly faulty.
Recheck system after repair.Ye s
Radio assembly faulty.
Recheck system after repair. Radio assembly faulty.
No
No
No Ye sYe s
Ye s
Ye s No Is radio operating normally?
Speaker wire harness faulty.
Speaker faulty. Is hiss noise produced by non-functioning speaker.
Is there continuity in speaker wire harness?
Temporarily install another speaker.
Function OK?
Radio assembly or power amplifier faulty.12 Tape Player ANY SPEAKER DOES NOT WORK BE-84
- BODY ELECTRICALAUDIO SYSTEM
2062 Author: Date:
1997 SUPRA (RM502U)