1997 TOYOTA SUPRA display

DIAGNOSTIC TROUBLE CODE CHECK PROCEDURE
Diagnostic Trouble
Code Check (Make a
note of and then clear)Confirmation
of SymptomsDiagnostic Trouble
Code CheckProblem Condition
Diagnostic Trouble
Code DisplayProblem symptoms
existSame diagnostic
trouble code is
displayedProblem is still occurring in the diagnostic
circuit.
Normal code is
displayedThe problem is still occurring in a place
other than in the diagnostic circuit.
(The diagnostic trouble code displayed
first is either for a past problem or it is a
secondary problem.)
No problem
symptoms existThe problem occurred in the diagnostic
circuit in the past.
Normal Code DisplayProblem symptoms
existNormal code is
displayedThe problem is still occurring in a place
other than in the diagnostic circuit.
No problem
symptoms existNormal code is
displayedThe problem occurred in a place other
than in the diagnostic circuit in the past.
IN-20- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
20 Author
: Date
:
1997 SUPRA (RM502U)
2. SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE CHECK
The diagnostic system in the TOYOTA SUPRA fulfills various functions. The first function is the Diagnostic
Trouble Code Check in which a malfunction in the signal circuits to the ECU is stored in code in the ECU
memory at the time of occurrence, to be output by the technician during troubleshooting. Another function
is the Input Signal Check which checks if the signals from various switches are sent to the ECU correctly.
By using these check functions, the problem areas can be narrowed down quickly and troubleshooting can
be performed effectively. Diagnostic functions are incorporated in the following systems in the TOYOTA SU-
PRA.
SystemDiagnostic Trouble
Code CheckInput Signal Check
(Sensor Check)Other Diagnosis
Function
Engine
Automatic Transmission
Anti-Lock Brake System
ABS & Traction Control System
Supplemental Restraint System
Cruise Control
Air Conditioning (with Check
Mode)
 (with Check
Mode)









Diagnostic Test
Mode
Diagnostic Test
Mode
Actuator Check
In diagnostic trouble code check, it is very important to determine whether the problem indicated by the diag-
nostic trouble code is still occurring or occurred in the past but returned to normal at present. In addition,
it must be checked in the problem symptom check whether the malfunction indicated by the diagnostic
trouble code is directly related to the problem symptom or not. For this reason, the diagnostic trouble codes
should be checked before and after the symptom confirmation to determine the current conditions, as shown
in the table below. If this is not done, it may, depending on the case, result in unnecessary troubleshooting
for normally operating systems, thus making it more difficult to locate the problem, or in repairs not pertinent
to the problem. Therefore, always follow the procedure in correct order and perform the diagnostic trouble
code check.

Diagnostic trouble code check
Making a note of and clearing of the diagnostic trouble codes displayed
Symptom confirmation
No problem symptoms
exist Problem symptoms
exist
Simulation test using the symptom
simulation methods

Normal code displayed

Problem symptoms exist
Normal code displayed

No problem symptoms exist Diagnostic trouble code check
Troubleshooting of problem indicated
by diagnostic trouble code
Diagnostic trouble code displayed

Problem symptoms exist
System Normal Troubleshooting of each
problem symptom
If a diagnostic trouble code was
displayed in the initial diagnostic
trouble code check, it indicates
that the trouble may have occurred
in a wire harness or connector in
that circuit in the past. Therefore,
check the wire harness and con-
nectors (See page IN-28).
- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN-21
21 Author
: Date
:
1997 SUPRA (RM502U)
Taking into account the above points, a flow chart showing how to proceed with troubleshooting using the
diagnostic trouble code check is shown below. This flow chart shows how to utilize the diagnostic trouble
code check effectively, then by carefully checking the results, indicates how to proceed either to diagnostic
trouble code troubleshooting or to troubleshooting of problem symptoms.

DTC No.
Indicates the diagnostic trouble code.

Page or Instructions
Indicates the page where the inspection procedure
for each circuit is to be found, or gives instructions
for checking and repairs.

Detection Item
Indicates the system of the problem or
contents of the problem.
Trouble Area
Indicates the suspect area of the
problem.
Mass Air Flow Circuit MalfunctionDetection Item

Open or short in mass air flow meter circuit

Mass air flow meter

ECM DTC No.
(See page)Trouble AreaMIL*MemoryP0100
(DI-23)
P0101
(DI-27)Mass Air Flow Circuit
Range/Performance Problem
Mass air flow meter
P0115
(DI-32)
Open or short in intake air temp. sensor circuit

Intake air temp. sensor

ECM Intake Air Temp. Circuit Malfunction P0110
(DI-28)
Engine Coolant Temp. Circuit
Range/Performance Problem
Open or short in engine coolant temp. sensor circuit

Engine coolant temp. sensor

ECM
P0120
(DI-37)
Throttle/ Pedal Position Sensor/Switch
ºAº Circuit Range/Performance
P0116
(DI-36)
Throttle/Pedal Position Sensor/Switch
ºAº Circuit Malfunction
Insufficient Coolant Temp. for Closed
Engine coolant temp. sensor

Cooling system Engine Coolant Temp. Circuit
Malfunction

Open or short in throttle position sensor circuit

Throttle position sensor

ECM

Throttle position sensor

Open or short in heated oxygen sensor circuit

Heated oxygen sensor
DTC CHART (SAE Controlled)
HINT: Parameters listed in the chart may not be exactly the same as your reading due to the type of instrument
or other factors.
If a malfunction code is displayed during the DTC check mode, check the circuit for that code listed in the table
below. For details of each code, turn to the page referred to under the ºSee pageº for the respective ºDTC No.º
in the DTC chart.
IN-24- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
24 Author
: Date
:
1997 SUPRA (RM502U)
4. DIAGNOSTIC TROUBLE CODE CHART
The inspection procedure is shown in the table below. This table permits efficient and accurate troubleshoot-
ing using the diagnostic trouble codes displayed in the diagnostic trouble code check. Proceed with trouble-
shooting in accordance with the inspection procedure given in the diagnostic chart corresponding to the
diagnostic trouble codes displayed. The engine diagnostic trouble code chart is shown below as an example.

- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN-25
25 Author
: Date
:
1997 SUPRA (RM502U)
5. PROBLEM SYMPTOMS TABLE
The suspect circuits or parts for each problem symptom are shown in the table below. Use this table to trou-
bleshooting the problem when a ºNormalº code is displayed in the diagnostic trouble code check but the
problem is still occurring. Numbers in the table indicate the inspection order in which the circuits or parts
should be checked.
HINT:
When the problem is not detected by the diagnostic system even though the problem symptom is present,
it is considered that the problem is occurring outside the detection range of the diagnostic system, or that
the problem is occurring in a system other than the diagnostic system.
Symptom
Suspect AreaSee page
Engine does not crank (Does not start)
No initial combustion (Does not start)
No complete combustion (Does not start)1. Starter and starter relay
1. ECM power source circuit
2. Fuel pump control circuit
3. Engine control module (ECM)
1. Starter signal circuit
2. Fuel pump control circuit1. Fuel pump control circuit
PROBLEM SYMPTOMS TABLE
1. Compression
2. Fuel pump control circuit 1. A/C signal circuit
2. Fuel pump control circuit 1. A/C signal circuit (Compressor circuit)
2. ECM power source circuit 1. Starter signal circuit
2. Fuel pump control circuit1. Starter signal circuit
2. Fuel pump control circuit
3. Compression
idling) Hot engine Cold engine (Difficult to start)Engine cranks normally (Difficult to start)

Problem Symptom
Page
Indicates the page where the flow chart for each circuit
is located.

Circuit Inspection, Inspection Order
Indicates the circuit which needs to be checked for each problem
symptom. Check in the order indicated by the numbers.

Circuit or Part Name
Indicates the circuit or part which needs to be checked.
ST-14,ST-15
DI-144
DI-148
SF-67
DI-141
EM-3
DI-825 DI-148
DI-148
DI-148
DI-148 DI-141
DI-141

BE4331
BE2826
Cassette Tape Slot Cover BE-74
- BODY ELECTRICALAUDIO SYSTEM
2052 Author
: Date
:
1997 SUPRA (RM502U)
6. CD Player/Disc Cleaning:
MAINTENANCE
If the disc gets dirty, clean the disc by wiping the surface from
the center to outside in the radial directions with a soft cloth.
NOTICE:
Do not use a conventional record cleaner or anti-static pre-
servative.
7. ANTI-THEFT SYSTEM
HINT:
The words ºANTI-THEFT SYSTEMº are displayed on the cas-
sette tape slot cover.
For operation instructions for the anti-theft system, please con-
sult the audio system section in the Owner's Manual (hereafter
called O/M).
(a) Setting system
The system is in operation once the customer has pushed
the required buttons and entered the customer-selected
3-digit ID number.
(Refer to the O/M section, ºSetting the anti-theft systemº)
HINT:

When the audio system is shipped, the ID number has not
been input, so the anti-theft system is not in operation.

If the ID number has not been input, the audio system re-
mains the same as a normal audio system.
(b) Anti-theft system operation
If the normal electrical power source (Connector or bat-
tery terminal) is cut off, the audio system becomes inoper-
able, even if the power supply resumes.
(c) Canceling system
The ID number chosen by the customer is input to cancel
the anti-theft system
(Refer to the O/M section, ºIf the system is activatedº)
HINT:
To change or cancel the ID number, please refer to the O/M
ºCancelling the systemº.

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.

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)

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)