1997 TOYOTA SUPRA cooling
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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.
Page 107 of 1807
N08744Sight Glass
AC0PZ-01
- AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC-3
2151 Author: Date:
1997 SUPRA (RM502U)
ON-VEHICLE INSPECTION
1. INSPECT REFRIGERANT VOLUME
Observe the sight glass on the liquid tube.
Test conditions:
Running engine at 1,500 rpm
Blower speed control switch at ºHIº position
A/C switch ON
Temperature control dial at ºCOOLº position
Fully open the doors
ItemSymptomAmount of refrigerantRemedy
1Bubbles present in sight glassInsufficient*
(1) Check for gas leakage with gas leak de-
tector and repair if necessary
(2) Add refrigerant until bubbles disappear
2No bubbles present in sight glassNone, sufficient or too muchRefer item 3 and 4
3No temperature difference between com-
pressor inlet and outletEmpty or nearly empty
(1) Check for gas leakage with gas leak de-
tector and repair if necessary
(2) Add refrigerant until bubbles disappear
4Temperature between compressor inlet and
outlet is noticeably differentCorrect or too muchRefer to items 5 and 6
5Immediately after air conditioning is turned
off, refrigerant in sight glass stays clearToo much
(1) Discharge refrigerant
(2) Evacuate air and charge proper amount
of purified refrigerant
6When air conditioning is turned off, refriger-
ant foams and then stays clearCorrect-
*: Bubbles in the sight glass with ambient temperatures higher than usual can be considered normal if cooling
is sufficient.
Page 109 of 1807
I01387
Condition : Periodically cools and then fails to cool
I01388
Condition: Insufficient cooling
- AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC-5
2153 Author: Date:
1997 SUPRA (RM502U)
(2) Moisture present in refrigeration system.
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
During operation, pressure on low
pressure side sometimes become
a vacuum and sometime normal
Moisture entered in refrigeration
system freezes at expansion valve
orifice and temporarily stops cycle,
by normal state is restored after a
time when the ice melts Drier oversaturated state
Moisture in refrigeration system
freezes at expansion valve orifice
and blocks circulation of refriger-
ant(1) Replace receiver
(2) Remove moisture in cycle
through repeatedly evacuating air
(3) Charge proper amount of new
refrigerant
(3) Insufficient cooling
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
Pressure low on both low and
high pressure sides
Bubbles seen in sight glass con-
tinuously
Insufficient cooling performance
Gas leakage at some place in re-
frigeration system Insufficient refrigerant in sys-
tem
Refrigerant leaking
(1) Check for gas leakage with gas
leak detector and repair if neces-
sary
(2) Charge proper amount of re-
frigerant
(3) If indicated pressure value is
near 0 when connected to gauge,
create the vacuum after inspecting
and repairing the location of the
leak
Page 110 of 1807
I01389
Condition: Insufficient cooling
I01449
Condition: Does not cool (Cools from time to time in some cases) AC-6
- AIR CONDITIONINGAIR CONDITIONING SYSTEM
2154 Author: Date:
1997 SUPRA (RM502U)
(4) Poor circulation of refrigerant
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
Pressure low in both low and
high pressure sides
Frost on tube from receiver to
unit
Refrigerant flow obstructed by dirt
in receiverReceiver cloggedReplace receiver
(5) Refrigerant does not circulate
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
Vacuum indicated on low pres-
sure side, very low pressure indi-
cated on high pressure side
Frost or dew seen on piping be-
fore and after receiver/ drier or ex-
pansion valve Refrigerant flow obstructed by
moisture or dirt in refrigeration sys-
tem
Refrigerant flow obstructed by
gas leakage from expansion valve
Refrigerant does not circulate
(1) Check expansion valve
(2) Clean out dirt in expansion
valve by blowing with air
(3) Replace receiver
(4) Evacuate air and charge new
refrigerant to proper amount
(5) For gas leakage from expan-
sion valve, replace expansion
valve
Page 111 of 1807
I01390
Condition: Insufficient cooling
I01392
Condition: Insufficient cooling
NOTE : These gauge indica-
tions are shown when the
refrigeration system has
been opened and the refrig-
erant charged without vacu-
um purging.
- AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC-7
2155 Author: Date:
1997 SUPRA (RM502U)
(6) Refrigerant overcharged or insufficient cooling of
condenser
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
Pressure too high on both low
and high pressure sides
No air bubbles seen through the
sight glass even when the engine
rpm is lowered Unable to develop sufficient per-
formance due to excessive refrig-
eration system
Insufficient cooling of condenser Excessive refrigerant in
cycle " refrigerant over charged
Condenser cooling " condenser
fins clogged of condenser fan
faulty
(1) Clean condenser
(2) Check condenser fan motor
operation
(3) If (1) and (2) are in normal
state, check amount of refrigerant
Charge proper amount of refriger-
ant
(7) Air present in refrigeration system
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
Pressure too high on both low
and high pressure sides
The low pressure piping hot to
touch
Bubbles seen in sight glass
Air entered in refrigeration system
Air present in refrigeration sys-
tem
Insufficient vacuum purging
(1) Check compressor oil to see if
it is dirty or insufficient
(2) Evacuate air and charge new
refrigerant
Page 112 of 1807
I01450
Condition: Insufficient cooling
I01393
Condition : Does not cool AC-8
- AIR CONDITIONINGAIR CONDITIONING SYSTEM
2156 Author: Date:
1997 SUPRA (RM502U)
(8) Expansion valve improperly
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
Pressure too high on both low
and high pressure sides
Frost or large amount of dew on
piping on low pressure side
Trouble in expansion valve
Excessive refrigerant in low
pressure piping
Expansion valve opened too
wide
Check expansion valve
Replace if defective
(9) Defective compression compressor
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
Pressure too high on low and
high pressure sides
Pressure too low on high pres-
sure side
Internal leak in compressor
Compression defective
Valve leaking or broken sliding
parts
Repair or replace compressor
Page 114 of 1807
N14519
Drain Hose AC-10
- AIR CONDITIONINGAIR CONDITIONING SYSTEM
2158 Author: Date:
1997 SUPRA (RM502U)
(b) Bring the gas leak detector close to the drain hose before
performing the test.
HINT:
After the blower motor has stopped, leave the cooling unit
for more than 15 minutes.
Expose the gas leak detector sensor under the drain
hose.
When bring the gas leak detector close to the drain hose,
make sure that the gas leak detector does not react to the
volatile gases.
If such reaction is unavoidable, the vehicle must be lifted up.
(c) If gas leak is not detected on the drain hose, remove the
blower resistor from the cooling unit. Then insert the gas
leak detector sensor into the unit and perform the test.
(d) Disconnect the connector and leave the pressure switch
for approx. 20 minutes. Then bring the gas leak detector
close to the pressure switch and perform the test.
(e) Bring the gas leak detector close to the refrigerant lines
and perform the test.
Page 151 of 1807
N08405
AC0RF-02
Z13470
Magnetic Clutch Control
Low Pressure Side High Pressure Side
ON (Continuity)
196 kPa
(2.0 kgf´cm
2, 28 psi)
OFF (No Continuity)3, 140 kPa
(32.0 kgf´cm2, 455 psi)
OFF (No Continuity)
Z13471
Cooling Fan Control
1, 520 kPa
(15.5 kgf´cm2, 220psi)
ON
(Continuity)
OFF
(No Continity)
1, 226 kPa
(12.5 kgf´cm
2, 178psi)
- AIR CONDITIONINGPRESSURE SWITCH
AC-73
2221 Author: Date:
1997 SUPRA (RM502U)
PRESSURE SWITCH
ON-VEHICLE INSPECTION
1. SET ON MANIFOLD GAUGE SET
(See page AC-18)
2. DISCONNECT CONNECTOR FROM PRESSURE
SWITCH
3. RUN ENGINE AT APPROX. 2,000 RPM
4. Magnetic Clutch Control:
INSPECT PRESSURE SWITCH OPERATION
( ): 2JZ-GTE
(a) Connect the positive (+) lead from the ohmmeter to termi-
nal 4 (1) and the negative (-) lead to terminal 1 (2).
(b) Check continuity between terminals when refrigerant
pressure is changed, as shown in the illustration.
If operation is not as specified, replace the pressure switch.
5. 2JZ-GTE Engine Models:
Condenser Fan Control:
INSPECT PRESSURE SWITCN OPERATION
(a) Connect the positive (+) lead from the ohmmeter to termi-
nal 2 and the negative (-) lead to terminal 3.
(b) Check continuity between terminals when refrigerant
pressure is changed, as shwn in the illustration.
If operation is not as specified, replace the pressure switch.
6. STOP ENGINE AND SET OFF MANIFOLD GAUGE SET
7. CONNECT CONNECTOR TO PRESSURE SWITCH