TOYOTA SUPRA 1997 Service Repair Manual
Page 231 of 1807
BE0EN-01
- BODY ELECTRICALAUDIO SYSTEM
BE-75
2053 Author: Date:
1997 SUPRA (RM502U)
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 inserts, 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
AntennaAntenna does not fully extend or fully retract.26
Antenna - related.27
NoiseNoise produced by vibration or shock while driving.28
Noise produced when engine starts.29
The term ºAMº includes LW,MW and SW, and the term ºFWº includes UKW.
Page 232 of 1807
V08418
Turn ignition Key from LOCK position to ACC position.
Troubleshooting for ANTI-THEFT SYSTEM
Display A:
ID Number is set.Display E:
ANTI-THEFT SYSTEM opera-
tion condition. (ID number input
error 10 times or more.)Display B
ºSEC display disappears after 1
second.Radio switch ON.
Take to designated radio
service station.Display BDisplay D
Refer to each
malfunction item.Normal
operation.
Radio switch ON. Normal operation.
Cancel ID number, refer to each malfunction item.
Ye s
No
OK
NG
ANTI-THEFT SYSTEM operation condition. (ID number input error 9 times or less.)
Input ID number to cancel ANTI-THEFT SYSTEM, and check display.
Display A"B Display B Display E
Display C"A
Radio switch ON.Refer to each
malfunction item.Take to designated
radio service station.ANTI-THEFT SYSTEM not can-
celled. (ID number input error 10
times or less.)
Display D
ANTI-THEFT SYSTEM cancelled.
Check audio system again.Normal operation.
OK
NG
Cancel ID number, refer to each malfunction item.
Liquid Crystal Display (LCD) or VFD for Audio System
Display ºAº Display ºBº Display ºCº
Display ºDº Example:Display ºEº
2 DIN Type
1 DIN TypeBlank
No Illumination
2 DIN Type
1 DIN Type 2 DIN Type
1 DIN Type Error Times2 DIN Type 1 DIN Type
Radio Display
1 DIN Type 2 DIN Type
HINT:
Refer to Owner's Manual for operation details of ANTI-THEFT SYSTEM.
When the ID number has been cancelled, reset the same number after completing the operation, or
inform the customer that it has been cancelled.
BE-76
- BODY ELECTRICALAUDIO SYSTEM
2054 Author: Date:
1997 SUPRA (RM502U)
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)