1995 TOYOTA SUPRA coolant temperature

EXHAUST GAS RECIRCULATION (EGR)
SYSTEM
EGR SYSTEM INSPECTION
1. CHECK AND CLEAN FILTER IN EGR VACUUM
MODULATOR
(a) Remove the cap and filter.
(b) Check the filter for contamination or damage.
(c) Using compressed air, clean the filter.
(d) Reinstall the filter and cap.
HINT: Install the filter with the coarser surface facing the at-
mospheric side outward.
2. INSTALL VACUUM GAUGE
Using a 3±way connector, connect a vacuum gauge to the
hose between the EGR valve and EGR vacuum modulator.
3. INSPECT SEATING OF EGR VALVE
Check that the engine starts and runs at idle.
4. INSPECT VSV OPERATION WITH COLD ENGINE
(a) The engine coolant temperature should be below 45°C
(113°F).
(b) Check that the vacuum gauge indicates zero at 2,500 rpm.
(c) Check that the EGR pipe is not hot.
5. INSPECT OPERATION OF VSV AND EGR VACUUM
MODULATOR WITH HOT ENGINE
(a) Warm up the engine to above 50°C (122°F).
(b) Check that the vacuum gauge indicates low vacuum at 3,500
rpm.
(c) Disconnect the vacuum hose from port R of the EGR vacuum
modulator and connect port R directly to the air intake
chamber with another hose.
(d) Check that the vacuum gauge indicates high vacuum at
3,500 rpm.
HINT: As exhaust gas is increasingly recirculated, the engine
will start to misfire.
6. REMOVE VACUUM GAUGE
Remove the vacuum gauge, and reconnect the vacuum
hoses to their proper locations. EG±168
± ENGINEEMISSION CONTROL SYSTEMS (2JZ±GE)

EXHAUST GAS RECIRCULATION (EGR)
SYSTEM
EGR SYSTEM INSPECTION
1. INSPECT AND CLEAN FILTER IN EGR VACUUM
MODULATOR
(a) Remove the cap and 2 filters.
(b) Check the filter for contamination or damage.
(c) Using compressed air, clean the filter.
(d) Reinstall the 2 filters and cap.
HINT: Install the filter with the coarser surface facing the at-
mospheric side (outward).
2. INSTALL VACUUM GAUGE
Using a 3±way connector, connect a vacuum gauge to the
hose between the EGR valve and vacuum modulator.
3. INSPECT SEATING OF EGR VALVE
Start the engine and check that the engine starts and runs at
at idle.
4. INSPECT VSV OPERATION WITH COLD ENGINE
(a) The coolant temperature should be below 50°C (122° F).
(b) From idle, race the engine to 3,500±4,000 rpm (throttle valve
opening angle to about 1/3 of maximum).
(c) Check that the EGR pipe is not hot.
(d) Check that the vacuum gauge indicates zero.
5. INSPECT VSV OPERATION WITH HOT ENGINE
(a) Warm up the engine to above 50°C (122°F)
(b) From idle, race the engine to 3,500±4,000 rpm (throttle valve
opening angle to about 1/3 of maximum).
(c) Check that the vacuum gauge indicates low vacuum.
6. REMOVE VACUUM GAUGE
Remove the vacuum gauge, and reconnect the vacuum
hoses to their proper locations.
7. INSPECT EGR VALVE
(a) Apply vacuum directly to the EGR valve with the engine
idling.
(b) Check that the engine runs rough or dies.
(c) Reconnect the vacuum hoses to the proper locations.
IF NO PROBLEM IS FOUND DURING THIS INSPECTION,
SYSTEM IS NORMAL; OTHERWISE INSPECT EACH
PART
VSV INSPECTION
(See VSV for EGR in SFI System) EG±180
± ENGINEEMISSION CONTROL SYSTEMS (2JZ±GTE)

GLOSSARY OF SAE AND TOYOTA TERMS
This glossary lists all SAE±J1930 terms and abbreviations used in this manual in compliance with SAE
recommendations, as well as their Toyota equivalents.
 
 
SAE ABBREVI±
ATIONS 
 SAE TERMS
 
 
TOYOTA TERMS
( ) ±± ABBREVIATIONS
 A/C Air Conditioning Air Conditioner
 ACL Air Cleaner Air Cleaner
AIRSecondary Air InjectionAir Injection (AI) AP Accelerator Pedal ± B+ Battery Positive Voltage +B, Battery Voltage BARO Barometric Pressure ±
 CAC Charge Air Cooler Intercooler
 CARB Carburetor Carburetor
 CFI Continuous Fuel Injection ±
 CKP Crankshaft Position Crank Angle
CLClosed LoopClosed Loop CMP Camshaft Position Cam Angle CPP Clutch Pedal Position ±
 CTOX Continuous Trap Oxidizer ±
 CTP Closed Throttle Position Idle ON (IDL ON)
 DFI Direct Fuel Injection (Diesel) Direct Injection (DI)
 DI Distributor Ignition ±
 
 
DLC1
DLC2
DLC3 
 
Data Link Connector 1
Data Link Connector 2
Data Link Connector 3 
 
1: Check Connector
2: Toyota Diagnosis Comunication Link (TDCL)
3: OBD II Diagnostic Connector
 DTC Diagnostic Trouble Code Diagnostic Code
 DTM Diagnostic Test Mode ±
 ECL Engine Control Level ±
 ECM Engine Control Module Engine ECU (Electronic Control Unit)
 ECT Engine Coolant Temperature Coolant Temperature, Water Temperature
(THW)
 
 
 
 
EEPROM
 
 
 
 
Electrically Erasable Programmable Read Only
Memory
 
 
 
 
Electrically Erasable Programmable Read Only
Memory (EEPROM),
Erasable Programmable Read Only Memory
(EPROM)
 
 
EFE 
 
Early Fuel Evaporation 
 
Cold Mixture Heater (CMH), Heat Control Valve
(HCV)
EGRExhaust Gas RecirculationExhaust Gas Recirculation (EGR) EI Electronic Ignition Toyota Distributorless Ignition (TDI) EM Engine Modification Engine Modification (EM) EPROM Erasable Programmable Read Only Memory Programmable Read Only Memory (PROM)
 EVAP Evaporative Emission Evaporative Emission Control (EVAP)
 FC Fan Control ±
 FEEPROM Flash Electrically Erasable Programmable
Read Only Memory ±
 
 FEPROM
 
 Flash Erasable Programmable Read Only
Memory 
 ±
 FF Flexible Fuel ±
 FP Fuel Pump Fuel Pump
 GEN Generator Alternator
 GND Ground Ground (GND)
HO2SHeated Oxygen SensorHeated Oxygen Sensor (HO2S)
± INTRODUCTIONGLOSSARY OF SAE AND TOYOTA TERMSIN±39

18. BRAKE PEDAL
(a) Check that pedal for smooth operation.
(b) Check that the pedal has the proper reserve
distance and freeplay.
(c) Check the brake booster function.
19. BRAKES
At a safe place, check that the brakes do not
pull to one side when applied.
20. PARKING BRAKE
(a) Check that the pedal has the proper travel.
(b) On a safe incline, check that the vehicle is
held securely with only the parking brake
applied.
21. AUTOMATIC TRANSMISSION PARK
MECHANISM
(a) Check the lock release button of the selector
lever for proper and smooth operation.
(b) On a safe incline, check that the vehicle is
held securely with the selector lever in the ºPº
position and all brakes released.
UNDER HOOD
22. WINDSHIELD WASHER FLUID
Check that there is sufficient fluid in the tank.
23. ENGINE COOLANT LEVEL
Check that the coolant level is between the
LEVEL lines on the see±through reservoir at
normal temperature (20°C (68°F)).
24. RADIATOR AND HOSES
(a) Check that the front of the radiator is clean
and not blocked with leaves, dirt or bugs.
(b) Check the hoses for cracks, kinks, rot or
loose connections.
25. BATTERY ELECTROLYTE LEVEL
Check the indicator.
When the indicator color is blue, the condition
is satisfactory. A red color indicates that dis-
tilled water must be added, and white indi-
cates that charging is necessary.
26. BRAKE FLUID LEVEL
Check that the brake fluid level is near the up-
per level line on the see±through reservoir.27. ENGINE DRIVE BELT
Check drive belt for fraying, cracks, wear or
oil contamination.
28. ENGINE OIL LEVEL
Check that level on the dipstick with the en-
gine turned off.
29. POWER STEERING FLUID LEVEL
Check the level on the dipstick.
The level should be in the ºHOTº or ºCOLDº
range depending on the fluid temperature.
30. A U TO M AT I C TRANSMISSION FLUID
LEVEL
(a) Park the vehicle on a level surface.
(b) With the engine idling and the parking and
foot brake applied, shift the selector into all
positions from ºPº to ºLº, and then shift into ºPº
position.
(c) Turn and pull out the dipstick and wipe off the
fluid with a clean rag.
Re±insert the dipstick fully and check that the
fluid level is in the ºHOTº range.
(d) Perform this check with the fluid at normal
driving temperature (70±80°C (158±176°F)).
If the level is at the low side, add fluid.
NOTICE: Do not overfill.
HINT: Wait about 30 minutes before checking
the fluid level after extended driving at high
speeds in hot weather, driving in heavy traffic
or with a trailer.
31. EXHAUST SYSTEM
Visually inspect for cracks, holes or loose
supports.
If any change in the sound of the exhaust or
smell of the exhaust fumes is noticed, have
the cause located and correted. MA±18
± MAINTENANCEGENERAL MAINTENANCE

INJECTORS REMOVAL
1. DRAIN ENGINE COOLANT
2. DISCONNECT CONTROL CABLES FROM THROTTLE
BODY
3. REMOVE INTAKE AIR CONNECTOR PIPE
(a) Disconnect these hoses:
(1) PS air hose from air connector pipe
(2) PCV hose from No.2 cylinder head cover
(b) Loosen the 2 hose clamps, and remove the air connector
pipe together with the hoses.
4. California only:
REMOVE VSV FOR FUEL PRESSURE CONTROL
(a) Disconnect the connector and hoses:
(1) VSV connector
(2) Vacuum sensing hose from fuel pressure control
(3) Vacuum sensing hose from air intake chamber
(b) Remove the bolt and VSV.
5. REMOVE EGR PIPE
(a) Loosen the union nut of the EGR pipe.
(b) Remove the 2 bolts, EGR pipe and gasket.
6. DISCONNECT EGR GAS TEMPERATURE SENSOR
CONNECTOR
(a) Disconnect the connector from the No.2 vacuum pipe.
(b) Disconnect the sensor connector from the wiring connector.
7. DISCONNECT NO.2 VACUUM PIPE FROM AIR INTAKE
CHAMBER AND INTAKE MANIFOLD
Remove the 2 nuts, and disconnect the vacuum pipe from the
air intake chamber and intake manifold.
8. DISCONNECT THROTTLE BODY BRACKET FROM
THROTTLE BODY AND CYLINDER HEAD
Remove the 4 nuts, and disconnect the throttle body bracket
from the throttle body and cylinder head. EG±204
± ENGINESFI SYSTEM (2JZ±GE)

ENGINE COOLANT TEMPERATURE
(ECT) SENSOR
COMPONENTS FOR REMOVAL AND
INSTALLATION
ECT SENSOR INSPECTION
1. DRAIN ENGINE COOLANT
2. REMOVE ECT SENSOR
(a) Disconnect the ECT sensor connector.
(b) Using SST, remove the ECT sensor and gasket.
SST 09205±76030 EG±242
± ENGINESFI SYSTEM (2JZ±GE)

C. Inspect VSV operation
(a) Check that air does not flow from port E to F.
(b) Apply battery voltage across the terminals.
(c) Check that air flows from port E to F.
If operation is not as specified, replace the VSV.
3. REINSTALL VSV
ENGINE COOLANT TEMPERATURE
(ECT) SENSOR
COMPONENTS FOR REMOVAL AND
INSTALLATION
± ENGINESFI SYSTEM (2JZ±GTE)EG±311

CIRCUIT DESCRIPTION
To obtain a high purification rate for the Co, Hc and NOx components of the exhaust gas, a three±way catalytic
converter is used, but for most efficient use of the three±way catalytic converter, the air±fuel ratio must be pre-
cisely controlled so that it is always close to the stoichiometric air±fuel ratio.
The oxygen sensor has the characteristic whereby its output voltage changes suddenly in the vicinity of the stoi-
chiometric air±fuel ratio. This characteristic is used to detect the oxygen concentration in the exhaust gas and
provide feedback to the computer for control of the air fuel ratio.
When the air±fuel ratio becomes LEAN, the oxygen concentration in the exhaust increases and the oxygen sen-
sor informs the ECM of the LEAN condition (small electromotive force: 0 V).
When the air±fuel ratio is RICHER than the stoichiometric air±fuel ratio the oxygen concentration in the exhaust
gas is reduced and the oxygen sensor informs the ECM of the RICH condition (large electromotive force: V).
The ECM judges by the electromotive force from the oxygen sensor whether the air±fuel ratio is RICH or LEAn
and controls the injection duration accordingly. However, if malfunction of the oxygen sensor causes an output
of abnormal electromotive force, the ECM is unable to perform accurate air±fuel ratio control.
The main heated oxygen sensors include a heater which heats the Zirconia element. The heater is controlled
by the ECM. When the intake air volume is low t(the temperature of the exhaust has is low) current flows to
the heater to heat the sensor for accurate oxygen concentration detection.)
Flange
Platinum Electrode
Solid Electrolyte
(Zirconia Element)
Platinum Electrode
Heater*
1
Coating (Ceramic)
Ideal Air±Fuel Mixture
Richer Ð Air Fuel ratio Ð Leaner
Trouble AreaDTC No.Diagnostic Trouble Code Detecting Condition
Exhaust Gas
Output Voltage
(1)*1Open or snort in heater circuit of main heated
oxygen sensor for 0.5 sec. or more.
(2) (Main heated*1) oxygen sensor signal voltage is
reduced to between 0.35 V and 0.70 V for 60
sec. under conditions (a) ~ (d):
(2) trip detection logic)*
2
(a) Engine coolant temp.: Between 80°C
(176°F and 95°C (203°F)
(b) Engine speed: 1,500 rpm or more
(c) Load driving (Example A/T in Overdrive
(5th for M/T), A/C ON, Flat road, 80 km/h (50
mph))
(d) (Main heated*
1) oxygen sensor signal
voltage: Alternating above and below 0.45 V
Atmosphere

Open or short in heater circuit of main heated
oxygen sensor

Main heated oxygen sensor heater

ECM

(Main heated*
1) oxygen sensor circuit

(Main heated*1) oxygen sensor
HINT: Diagnostic trouble code ª21º is for the (main heated*1) oxygen sensor (Fr) circuit.
Diagnostic trouble code ª28º is for the (main heated*
1) oxygen sensor (Rr) circuit.
*1: Main heated oxygen sensor ONLY for California specification vehicles.
*2: See page EG±397.
DTC 21 28 (Main Heated*1) Oxygen Sensor Circuit
± ENGINE2JZ±GE ENGINE TROUBLESHOOTINGEG±419