Engine Controls - System/component Tests: Other Toyota Supra A80

INTAKE AIR CONTROL VALVE SYSTEM

Note. Intake Air Control Valve (IACV) system may also be referred to as Acoustic Control Induction System (ACIS).

Note. Supra Turbo models use an intake air control valve located on air inlet pipe to the turbocharger. For testing of intake air control valve, see TURBOCHARGERS (SUPRA) under AIR INDUCTION SYSTEMS.

Scheme 12

Scheme 13

Scheme 14

1. Using 3-way connector, connect vacuum gauge in vacuum line to the actuator valve, located on side of air intake chamber. (Scheme 13) Start engine. With engine idling, ensure no vacuum reading is obtained.
2. Fully open throttle and ensure vacuum reading momentarily reads at least 9.8 in. Hg and actuator valve rod pulls downward. If actuator valve rod fails to pull downward, proceed to next step.
3. Disconnect vacuum hose from actuator valve, located on side of air intake chamber. It may be necessary to remove air intake chamber for access to actuator valve.
4. Using vacuum pump, apply approximately 16 in. Hg of vacuum to actuator valve. Ensure actuator valve rod pulls downward and remains pulled downward for at least one minute. NOTE: If actuator valve rod does not move downward, it may be necessary to rotate adjusting screw near the shaft located in the air intake chamber. (Scheme 13)
5. Replace actuator valve if defective. If actuator valve operates correctly, reconnect vacuum hose. Proceed to next step.
6. Disconnect vacuum hoses from vacuum tank, located below air intake chamber. (Scheme 13) Apply air pressure to port "A" on vacuum tank. Ensure air passes out port "B". Perform STEP 1. (Scheme 14) Apply air pressure to port "B". Ensure air does not pass out port "A". Perform STEP 1. (Scheme 14)
7. Plug port "B" on vacuum tank. Using vacuum pump, apply approximately 16 in. Hg of vacuum to port "A". Perform STEP 2. (Scheme 14) Ensure vacuum reading holds for at least one minute. Replace vacuum tank if defective and recheck system operation. If vacuum tank is okay, reconnect vacuum hoses. Proceed to next step.
8. Disconnect negative battery cable. Disconnect electrical connector from intake air control valve Vacuum Switching Valve (VSV), located near vacuum tank. (Scheme 13) It may be necessary to remove vacuum tank for access to VSV.
9. Using ohmmeter, ensure continuity exists between electrical terminals on VSV and resistance is 39-45 ohms. Check that no continuity exists between each electrical terminal and body of VSV.
10. Apply air pressure to port "B" and ensure air passes out filter. Perform STEP 1. (Scheme 12) Connect battery voltage and ground to VSV terminals. Apply air pressure to port "B" and ensure air passes out port "A". Perform STEP 2. (Scheme 12) Replace VSV if defective. Reconnect negative battery cable. Recheck system operation.
11. If VSV is okay, reinstall VSV and negative battery cable. Ensure ignition is off. Raise floor mat on passenger's side for access to Engine Control Module (ECM). Remove ECM protector, located above ECM. Loosen bolt and disconnect electrical connectors from ECM.
12. Install Check Harness (SST 09990-01000) between ECM and ECM electrical connector. (Scheme 15) Turn ignition on. Check voltage between terminal No. 39 and chassis ground. (Scheme 15)
13. Voltage should be 9-14 volts. If voltage is not within specification, check for defective EFI main relay or wiring harness between EFI main relay and ECM. See EFI MAIN RELAY under «RELAYS»(ref-21358-S39095016732001010300000). See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-21402) article.
14. If EFI main relay and wiring harness are okay, check ECM ground circuit. If ECM ground circuit is okay, substitute another ECM and recheck system operation.

Scheme 15

TURBOCHARGERS

Note. No. 1 and 2 turbochargers are used along with various operating valves, actuators, intake air control valve and vacuum switching valves. For description of system operation, see AIR INDUCTION SYSTEM in THEORY/OPERATION article.

Initial Checks

1. Check air intake system for cracks or restrictions. Inspect exhaust system for leaks or restrictions.
2. Check air intake system and exhaust system for signs of oil leaks from turbocharger. Oil leaks can be caused by worn oil seals in the turbocharger.

Note. Turbo pressure may be referred to as boost pressure. Tachometer is required when checking turbo pressure. If installing tachometer, ensure it is connected to proper terminals. For tachometer connections, see IDLE SPEED & MIXTURE in ADJUSTMENTS article.

Scheme 16

Turbo Pressure Check

1. Ensure intake air hoses are connected. Install hose, 3-way connector and pressure gauge between intake manifold gas filter and turbo pressure sensor. (Scheme 17)
2. Drive vehicle with engine at 5600 RPM or more with throttle fully open and transmission in 1st gear ("L" range), and note turbo pressure. Turbo pressure should be 8.8-10.8 psi (.62-.76 kg/cm2).
3. If turbo pressure is less than specified, check intake air and exhaust systems for leaks. If no leaks exist, replace turbocharger assemblies. If turbo pressure exceeds specification, check wastegate actuator hose for leaks or cracks. If no leaks or cracks exist, replace turbocharger assemblies. Remove test equipment.

Scheme 17

Turbocharger Control Circuit

1. Check exhaust by-pass valve Vacuum Switching Valve (VSV), exhaust gas control VSV and intake air control valve VSV. See EXHAUST GAS CONTROL VSV, EXHAUST BY-PASS VALVE (VSV), INTAKE AIR CONTROL VALVE VSV & WASTEGATE VSV under «ENGINE SENSORS & SWITCHES»(ref-21358-S18229764562001010300000).
2. If all vacuum switching valves operate properly, ensure ignition is off. Raise floor mat on passenger's side for access to Engine Control Module (ECM). Turn ignition on.
3. Using voltmeter, check voltage between terminal No. 38 (Green/Red) wire, No. 39 (Green/Yellow) wire and No. 40 (Green/Black) wire of E9 connector and chassis ground. (Scheme 21)
4. Voltage should be 9-14 volts with engine idling. If voltage is correct, proceed to step 6). If voltage is not within specification, check for defective EFI No. 2 relay or wiring harness between EFI No. 2 relay and ECM. See EFI NO. 2 RELAY under «RELAYS»(ref-21358-S39095016732001010300000). See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-21402) article.
5. If EFI No. 2 relay and wiring harness are okay, check ECM ground circuit. If ECM ground circuit is okay, substitute another ECM and recheck system operation.
6. Check exhaust gas control valve actuator, exhaust by-pass valve actuator and intake air control valve actuator. See EXHAUST GAS CONTROL VALVE ACTUATOR, EXHAUST BY-PASS VALVE ACTUATOR & VALVE and INTAKE AIR CONTROL VALVE ACTUATOR under «TURBOCHARGERS»(ref-21358-S26457057522001010300000).

Exhaust Gas Control Valve Actuator

1. Disconnect hose from exhaust gas control valve actuator. (Scheme 16) Using Pressure Gauge/Pump (SST 09992-00241), apply about 7.1 psi (.50 kg/cm2) of pressure to exhaust gas control valve actuator. Ensure exhaust gas control valve actuator rod and valve moves.
2. Replace exhaust gas control valve assembly if exhaust gas control valve actuator rod does not move. Remove pressure gauge/pump and reconnect hose.

Air By-Pass Valve

1. Disconnect hoses from air by-pass valve, located on No. 4 air tube. (Scheme 16) Apply air pressure to port "A". Ensure air does not pass out port "B". Perform STEP 1. (Scheme 18)
2. Using vacuum pump, apply vacuum to air by-pass valve. Apply air pressure to port "A". Ensure air passes out port "B". Perform STEP 2. (Scheme 18) Replace air by-pass valve if defective. Disconnect vacuum pump. Reconnect hoses.

Scheme 18

Exhaust By-Pass Valve Actuator & Valve

1. Disconnect hoses from exhaust by-pass valve actuator. (Scheme 16) Place plug on one hose fitting on exhaust by-pass valve actuator.
2. Using Pressure Gauge/Pump (SST 09992-00241), apply about 14.2 psi (1.00 kg/cm2) of pressure to other hose fitting on exhaust by-pass valve actuator. Ensure exhaust by-pass valve actuator rod moves and exhaust by-pass valve opens. CAUTION: DO NOT apply more than 27.2 psi (1.91 kg/cm2) pressure to exhaust by-pass valve actuator.
3. Replace No. 2 turbocharger assembly if exhaust by-pass valve actuator rod does not move. Remove pressure gauge/pump and plug. Reconnect hoses.

Intake Air Control Valve Actuator

1. Disconnect hose from intake air control valve actuator. (Scheme 16) Using Pressure Gauge/Pump (SST 09992-00241), apply about 7.1 psi (.50 kg/cm2) of pressure to intake air control valve actuator.
2. Ensure intake air control valve actuator rod moves and intake air valve opens. Replace intake air control valve assembly if intake air control valve actuator rod does not move. Remove pressure gauge/pump and reconnect hose.

Pressure Tank

1. Disconnect hoses from pressure tank, located below air intake chamber. (Scheme 19) Apply air pressure to port "A". Ensure air passes out port "B". Perform STEP 1. (Scheme 20)
2. Apply air pressure to port "B". Ensure air does not pass out port "A". Perform STEP 2. (Scheme 20) Using vacuum pump, apply about 18 in. Hg of vacuum to port "A". Perform STEP 3. (Scheme 20) Ensure vacuum reading holds for at least one minute. Replace pressure tank if defective. Remove vacuum pump and reconnect hoses.

Scheme 19

Scheme 20

Wastegate Actuator

1. Disconnect hose from wastegate actuator. (Scheme 16) Using Pressure Gauge/Pump (SST 09992-00241), apply about 17.4 psi (1.22 kg/cm2) of pressure to wastegate actuator. Ensure wastegate actuator rod moves. CAUTION: DO NOT apply more than 27.2 psi (1.91 kg/cm2) pressure to wastegate actuator.
2. Replace No. 1 turbocharger assembly if wastegate actuator rod does not move. Remove pressure gauge/pump and reconnect hose.

Impeller Wheel Rotation

Disconnect air cleaner hose. Rotate impeller wheel in air intake side of each turbocharger and verify smooth rotation. Replace turbocharger if impeller wheel binds, drags or does not rotate smoothly.

Turbine Shaft End Play & Radial Play

1. Remove turbochargers from exhaust manifold. Install dial indicator with stem resting against end of shaft on impeller wheel (intake side).
2. Push turbine wheel (exhaust) side of shaft toward dial indicator and zero dial indicator. Push impeller wheel (intake side) away from dial indicator, and note end play reading on dial indicator.
3. Remove dial indicator and reinstall with stem extending into oil drain tube hole and against center of turbine shaft. Pull impeller wheel (intake side) and turbine wheel upward toward dial indicator and zero dial indicator.
4. Push impeller wheel and turbine wheel downward and note radial play reading on dial indicator. Repeat procedure on both turbochargers. Replace turbocharger if end play or radial play exceeds specification. See «TURBOCHARGER SPECIFICATIONS»(ref-21358-S22936135962001010300000) table. Reinstall turbochargers.

TURBOCHARGER SPECIFICATIONS

Power & Ground Circuits

For testing of power and ground circuits, see information in PIN VOLTAGE CHARTS article. See ECM LOCATION table for identifying ECM mounting locations.

ECM LOCATION

Note. Fig. (Scheme 21) identifies ECM terminals used for performing tests on various components in this article.

Scheme 21

AIRFLOW METER

Note. Airflow meter may be referred to as Volume Airflow (VAF) meter or Mass Airflow (MAF) meter.

Turbo

1. Turn ignition off. Disconnect electrical connector from airflow meter. Note airflow meter terminal identification. (Scheme 22)and (Scheme 23).
2. Using ohmmeter, measure resistance between specified terminals. See «AIRFLOW METER RESISTANCE SPECIFICATIONS»(ref-21358-S21414333382001010300000) table. Replace airflow meter if resistance is not within specification.
3. To check airflow meter operation, ensure electrical connector is installed on airflow meter. Connect voltmeter leads to proper terminals on airflow meter with electrical connector installed. (Scheme 24)
4. Turn ignition on. Apply air into airflow meter and note voltage reading. (Scheme 24) While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate. Remove voltmeter.

Non-Turbo

1. Turn ignition off. Disconnect electrical connector from airflow meter. Note airflow meter terminal identification. (Scheme 22)and (Scheme 23).
2. Using ohmmeter, measure resistance between specified terminals. See «AIRFLOW METER RESISTANCE SPECIFICATIONS»(ref-21358-S21414333382001010300000) table. Replace airflow meter if resistance is not within specification.

Scheme 22

Scheme 23

Scheme 24

AIRFLOW METER RESISTANCE SPECIFICATIONS

For checking camshaft position sensor, see CAMSHAFT POSITION SENSOR under IGNITION CHECKS described in BASIC TESTING article.

COOLANT TEMPERATURE SENSOR

Coolant temperature sensor may be referred to as engine coolant temperature sensor. See ENGINE COOLANT TEMPERATURE (ECT) SENSOR under ENGINE SENSORS & SWITCHES .

For checking crankshaft position sensor, see CRANKSHAFT POSITION SENSOR under IGNITION CHECKS in BASIC TESTING article.

EGR GAS TEMPERATURE SENSOR

Note. The EGR gas temperature sensor may be referred to as EGR function sensor.

1. Remove EGR gas temperature sensor from side of EGR valve. Place threaded end of sensor and thermometer in container of oil.
2. Attach ohmmeter to electrical terminals. Heat oil and note resistance at specified temperature. See «EGR GAS TEMPERATURE SENSOR SPECIFICATIONS»(ref-21358-S42836501092001010300000) table. Replace EGR gas temperature sensor if resistance is not within specification.

EGR GAS TEMPERATURE SENSOR SPECIFICATIONS

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

1. Ensure ignition is off. Disconnect electrical connector from ECT sensor. The ECT sensor is located in engine coolant passage near cylinder head or thermostat housing. To verify wire colors for proper identification, see appropriate wiring diagram information in «WIRING DIAGRAMS»(ref-21402) article. NOTE: The ECT may be also identified using appropriate illustration in «THEORY/OPERATION»(ref-21401) article.
2. Using ohmmeter, check resistance between ECT sensor electrical terminals. Resistance should be within specification at designated temperature. (Scheme 25) Replace ECT sensor if resistance is not within specification.

Scheme 25

KNOCK SENSOR

1. Knock sensor(s) are located on the cylinder block. (Scheme 26) Remove knock sensor from cylinder block before testing. See «REMOVE/INSTALL/OVERHAUL»(ref-21447) article.
2. Using ohmmeter, check that no continuity exists between electrical terminal of knock sensor and body of knock sensor. Replace knock sensor if continuity exists.

Scheme 26

PARK/NEUTRAL SWITCH CIRCUIT

Note. Park/neutral switch may be referred to as Park/Neutral Position (PNP) switch.

1. Check for diagnostic trouble codes while cranking the engine. See articles listed below for accessing diagnostic trouble codes: «TESTS W/CODES - NON-TURBO»(ref-21403) «TESTS W/CODES - TURBO»(ref-21404)
2. With transmission/transaxle in Park, MIL should flash steady indicating normal operation. With transmission/transaxle in Drive, MIL should flash diagnostic trouble Code 51. This indicates park/neutral switch circuit is okay.
3. If diagnostic trouble Code 51 exists with transmission/transaxle in Park and Drive, check wiring harness between park/neutral switch and Engine Control Module (ECM). See «ECM LOCATION»(ref-21358-S17530113232001010300000) table. If wiring harness is okay, substitute ECM with another ECM and recheck operation. ECM LOCATION Model Location Supra Below Passenger Side Of Dash Underneath Carpet On The Floor
4. If normal operation is displayed by MIL with transmission/transaxle in Park and Drive, check park/neutral switch. See PARK/NEUTRAL SWITCH under «ENGINE SENSORS & SWITCHES»(ref-21358-S18229764562001010300000) . If park/neutral switch is okay, substitute ECM with another ECM and recheck operation. See «ECM LOCATION»(ref-21358-S17530113232001010300000) table.

PARK/NEUTRAL SWITCH

Note. Park/neutral switch may be referred to as Park/Neutral Position (PNP) switch.

A/T Models

Disconnect electrical connector from park/neutral switch at transmission or transaxle. Note terminal identification. (Scheme 27) Using ohmmeter, check for continuity at specified terminals with gearshift in proper positions. See PARK/NEUTRAL SWITCH SPECIFICATIONS table. Replace switch if defective.

PARK/NEUTRAL SWITCH SPECIFICATIONS

Scheme 27

SUB-OXYGEN SENSOR

Note. Sub-oxygen sensor may be used only on California applications on some models. See OXYGEN SENSOR APPLICATION table.

1. Warm engine to normal operating temperature. Check Engine Control Module (ECM) for stored diagnostic trouble code(s). See RETRIEVING TROUBLE CODES in articles listed below: «TESTS W/CODES - NON-TURBO»(ref-21403) «TESTS W/CODES - TURBO»(ref-21404) If sub-oxygen sensor or circuit fails, a diagnostic trouble Code 27 will set in Engine Control Module (ECM) memory. Clear diagnostic trouble code if present. See CLEARING TROUBLE CODES in articles listed below: «TESTS W/CODES - NON-TURBO»(ref-21403) «TESTS W/CODES - TURBO»(ref-21404)
2. Drive vehicle between 50 and 62 MPH for at least 5 minutes in 4th or 5th gear (M/T) or Drive (A/T). DO NOT drive vehicle at speeds exceeding 62 MPH, or trouble code will be canceled.
3. Stop engine and turn ignition off. Repeat steps and note if diagnostic trouble Code 27 exists again. If trouble Code 27 exists again, check sub-oxygen sensor circuit for continuity, shorts or grounds. Replace sub-oxygen sensor if circuit is okay.

OXYGEN SENSOR HEATER

Note. Oxygen sensor heater may be used only on California applications on some models. See OXYGEN SENSOR APPLICATION table.

Turbo & Non-Turbo CA

1. Disconnect electrical connector from oxygen sensor. Using ohmmeter, measure resistance between oxygen sensor terminals +B and HT. (Scheme 28)
2. Replace oxygen sensor if resistance is not within specification. See «OXYGEN SENSOR HEATER RESISTANCE SPECIFICATIONS»(ref-21358-S14120053492001010300000) table.

OXYGEN SENSOR HEATER RESISTANCE SPECIFICATIONS

Scheme 28

SUB-OXYGEN SENSOR HEATER

Note. Sub-oxygen sensor heater may be used only on California applications on some models. See OXYGEN SENSOR APPLICATION table.

Disconnect electrical connector from sub-oxygen sensor. Using ohmmeter, measure resistance between sensor terminals +B and HT. (Scheme 29) Replace sub-oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C).

Scheme 29

PICK-UP COILS

See PICK-UP COIL AIR GAP and PICK-UP COIL RESISTANCE under IGNITION CHECKS in BASIC TESTING article.

THROTTLE POSITION SENSOR

1. Turn ignition off. Disconnect electrical connector from Throttle Position Sensor (TPS) on throttle body. Note terminal identification. (Scheme 30)and (Scheme 31). NOTE: Some models require that vacuum be applied to throttle opener before checking TPS. See «TPS RESISTANCE SPECIFICATIONS»(ref-21358-S24025638062001010300000) table.
2. Insert specified thickness feeler gauge between throttle stop screw and throttle lever and check resistance or continuity. See «TPS RESISTANCE SPECIFICATIONS»(ref-21358-S24025638062001010300000) table. Replace or adjust TPS if not within specification.

Scheme 30

Scheme 31

TPS RESISTANCE SPECIFICATIONS

1. Disconnect electrical connector from sub-throttle actuator. (Scheme 32) Note terminal identification. (Scheme 33)
2. Using ohmmeter, measure resistance between specified terminals. See «SUB-THROTTLE ACTUATOR RESISTANCE SPECIFICATIONS»(ref-21358-S10350463362001010300000) table. Replace sub-throttle actuator if resistance is not within specification.

SUB-THROTTLE ACTUATOR RESISTANCE SPECIFICATIONS

Scheme 32

Scheme 33

1. Disconnect electrical connector from sub-throttle actuator and sub-throttle position sensor. (Scheme 32)
2. Remove screws and sub-throttle actuator. (Scheme 32) Ensure no clearance exists between throttle stop screw and throttle valve gear with sub-throttle valve fully closed. Perform STEP 1. (Scheme 34), (Scheme 35) and (Scheme 36).
3. With sub-throttle valve fully closed, insert specified thickness feeler gauge between throttle stop screw and throttle valve gear and check resistance between specified terminals. See «SUB-THROTTLE POSITION SENSOR RESISTANCE SPECIFICATIONS»(ref-21358-S37069104502001010300000) table. Perform STEPS 2 and 3. (Scheme 34), (Scheme 35) and (Scheme 36).
4. Replace or adjust sub-throttle position sensor if resistance is not within specification. Reinstall sub-throttle actuator and electrical connectors.

SUB-THROTTLE POSITION SENSOR RESISTANCE SPECIFICATIONS

Scheme 34

Scheme 35

Scheme 36

1. Ensure ignition is off. To check turbo pressure sensor supply voltage, disconnect electrical connector from turbo pressure sensor. Turbo pressure sensor is located on air intake chamber, near throttle cable bracket. (Scheme 38) NOTE: Turbo pressure sensor has a vacuum hose connected to it and may be identified by wire colors. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-21402) article.
2. Turn ignition on. Using voltmeter, measure voltage between terminals VC and E2 of wiring harness side of the turbo pressure sensor electrical connector. The VC and E2 terminals are the outer terminals on the electrical connector. Voltage should be 4.5-5.5 volts.
3. If voltage is not within specification, check wiring circuit. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-21402) article. If voltage is correct, turn ignition off. Reinstall electrical connector on turbo pressure sensor.
4. To check turbo pressure sensor output voltage, disconnect turbo pressure sensor vacuum hose from intake manifold. Disconnect negative battery cable. Remove passenger's side door scuff plate.
5. Remove carpet below instrument panel on passenger's side for access to Engine Control Module (ECM), located on floor panel. Remove ECM protector, located above ECM. Remove nuts and separate ECM from floor panel.
6. Disconnect electrical connectors from ECM and install Check Harness (SST 09990-01000) between wiring harness and ECM. (Scheme 37) Reconnect negative battery cable.
7. Turn ignition on. Connect voltmeter to terminals PIM and E2 of check harness. (Scheme 37) Measure and record output voltage under ambient atmospheric pressure. Attach vacuum pump to turbo pressure sensor.
8. Apply vacuum in specified increments and measure output voltage drop at each increment. See «TURBO PRESSURE SENSOR OUTPUT VOLTAGE SPECIFICATIONS»(ref-21358-S13588071262001010300000) table. TURBO PRESSURE SENSOR OUTPUT VOLTAGE SPECIFICATIONS Applied Vacuum: In. Hg Output Voltage Drop 3.94.15-.35 7.87.40-.60 11.81.65-.85 15.75.90-1.10 19.69 1.15-1.35
9. Replace turbo pressure sensor if output voltage drop is not within specification. Remove check harness. Reinstall all electrical connectors, ECM and vacuum hose.

Scheme 37

1. Disconnect electrical connector and hoses from appropriate Vacuum Switching Valve. For appropriate VSV location, see «VACUUM SWITCHING VALVE LOCATIONS»(ref-21358-S01521181502001010300000) table. (Scheme 38) NOTE: Vacuum switching valve may also be identified by wire colors. See appropriate wiring diagram information in «WIRING DIAGRAMS»(ref-21402) article. VACUUM SWITCHING VALVE LOCATIONS Application Location Exhaust By-Pass Valve VSV Passenger's Side Rear Corner Of Engine, Near Turbocharger Exhaust Gas Control Valve VSV Front Corner Of Engine, By Air Intake Intake Air Control Valve VSV Rear Corner Of Engine, Above Turbocharger Wastegate VSV Front Corner Of Engine, By Air Intake
2. Remove VSV. Using ohmmeter, check resistance and for continuity between VSV electrical terminals. Replace VSV if no continuity exists or resistance is not within specification. See «VACUUM SWITCHING VALVE RESISTANCE SPECIFICATIONS»(ref-21358-S24964732372001010300000) table. VACUUM SWITCHING VALVE RESISTANCE SPECIFICATIONS Application Ohms @ 68°F (20°C) Exhaust By-Pass Valve VSV 22-26 Exhaust Gas Control Valve VSV 38.5-44.5 Intake Air Control Valve VSV 38.5-44.5 Wastegate VSV 22-26
3. Ensure no continuity exists between each electrical terminal and VSV body. Replace VSV if continuity exists between electrical terminal and VSV body.
4. On exhaust gas control valve VSV or intake air control valve VSV, apply air pressure to port "E". Ensure air passes from the filter. (Scheme 39)and (Scheme 40).
5. Connect battery voltage and ground to VSV terminals. Apply air pressure to port "E". Ensure air passes from port "F". (Scheme 39)and (Scheme 40). Replace VSV if defective and reinstall VSV.
6. On exhaust by-pass valve VSV or wastegate VSV, apply air pressure to port "E". Ensure no air passes from port "F". (Scheme 39)and (Scheme 40).
7. Connect battery voltage and ground to VSV terminals. Apply air pressure to port "E". Ensure air passes from port "F". (Scheme 39)and (Scheme 40). Replace VSV if defective.

Scheme 38

Scheme 39

Scheme 40

VEHICLE SPEED SENSOR

1. Vehicle speed sensor is located on transmission/transaxle and contains a 3-wire connector. Connect voltmeter and battery voltage to vehicle speed sensor terminals. (Scheme 41)
2. While rotating vehicle speed sensor shaft, ensure voltage changes from zero to at least 11 volts. Voltage should change 4 times per revolution of the shaft. Replace vehicle speed sensor if voltage does not change as specified.

Scheme 41

FUEL PUMP ELECTRONIC CONTROL UNIT

See FUEL DELIVERY under FUEL SYSTEM .

EFI MAIN RELAY

Note. Supra Turbo models also use a EFI No. 2 relay along with EFI main relay. For testing procedures, see EFI NO. 2 RELAY under RELAYS.

1. Ensure ignition is off. Remove EFI main relay. See «EFI MAIN RELAY LOCATION»(ref-21358-S32861934182001010300000) table. Using ohmmeter, check continuity between specified terminals. (Scheme 42)and (Scheme 43).
2. Check EFI main relay operation by applying battery voltage and ground and checking continuity between specified terminals. (Scheme 42)and (Scheme 43). Replace EFI main relay if defective.

Note. The EFI main relay may also be identified using appropriate illustration in THEORY/OPERATION article or wire color. See appropriate wiring diagram in WIRING DIAGRAMS article.

EFI MAIN RELAY LOCATION

Scheme 42

Scheme 43

EFI NO. 2 RELAY

Note. EFI No. 2 relay may also be referred to as No. 2 EFI relay.

1. Ensure ignition is off. Remove EFI No. 2 relay from fuse/relay box near driver's side front fenderwell.
2. Using ohmmeter, check continuity between specified terminals. (Scheme 42)and (Scheme 43). Check EFI No. 2 relay operation by applying battery voltage and ground and checking continuity between specified terminals. (Scheme 42)and (Scheme 43). Replace EFI No. 2 relay if defective.

Note. EFI No. 2 relay may also be identified using appropriate illustration in THEORY/OPERATION article or wire color. See appropriate wiring diagram in WIRING DIAGRAMS article.

IGNITION MAIN RELAY

See IGNITION MAIN RELAY under IGNITION SYSTEM .

FUEL DELIVERY

Note. For fuel system pressure testing, see BASIC TESTING article.

Circuit Opening Relay

See CIRCUIT OPENING RELAY under RELAYS .

See EFI MAIN RELAY under RELAYS .

See EFI NO. 2 RELAY under RELAYS .

Fuel pump Electronic Control Unit (ECU) is used for controlling fuel pump. If failure exists, diagnostic trouble Code 78 will be set in Engine Control Module (ECM) memory. For diagnostic trouble code diagnosis, see articles listed below

1. «TESTS W/CODES - NON-TURBO»(ref-21403)
2. «TESTS W/CODES - TURBO»(ref-21404)

Fuel Pump Relay

See FUEL PUMP RELAY under RELAYS .

FUEL CONTROL

Note. Fuel injector solenoid resistor may also be referred to as MFI resistor, SFI resistor or solenoid resistor.

Fuel Injector Solenoid Resistor (Turbo)

1. Ensure ignition is off. Disconnect fuel injector solenoid resistor electrical connector. See «FUEL INJECTOR SOLENOID RESISTOR LOCATION»(ref-21358-S38363664542001010300000) table. NOTE: Fuel injector solenoid resistor may also be identified using appropriate illustration in «THEORY/OPERATION»(ref-21401) article.
2. Using ohmmeter, measure resistance between terminal +B and other fuel injector solenoid resistor electrical terminals. (Scheme 44) Replace fuel injector solenoid resistor if resistance is not within specification. See «FUEL INJECTOR SOLENOID RESISTOR SPECIFICATIONS»(ref-21358-S36595803642001010300000) table.

FUEL INJECTOR SOLENOID RESISTOR LOCATION

FUEL INJECTOR SOLENOID RESISTOR SPECIFICATIONS

Scheme 44

Fuel Injectors

1. Ensure ignition is off. Disconnect electrical connector at fuel injector. Using ohmmeter, measure resistance between fuel injector electrical terminals. Replace fuel injector if resistance is not within specification. See «FUEL INJECTOR RESISTANCE SPECIFICATIONS»(ref-21358-S20377941492001010300000) table.
2. To check fuel injector spray pattern and volume, remove fuel injector. See «REMOVE/INSTALL/OVERHAUL»(ref-21447) article. Disconnect fuel hose from fuel filter outlet. Use Delivery Hose (09268-41045) to install fuel injector between fuel filter and fuel pressure regulator. (Scheme 45)and (Scheme 46).
3. Place fuel injector into a clean graduated container. Place vinyl tube on end of fuel injector to prevent fuel spillage. Install Jumper Wire (SST 09843-18020) between +B and FP terminals of data link connector No. 1. Turn ignition on, with engine off to pressurize fuel system. NOTE: For proper location of data link connector No. 1 and terminal identification, see «BASIC TESTING»(ref-21327) article. Jumper wire is installed in data link connector No. 1 when checking fuel pump operation and fuel pressure.
4. Connect fuel injector tester to fuel injector for 15 seconds. Use Fuel Injector Tester (09842-30060) for Turbo or (09842-30070) for Non-Turbo.
5. Measure fuel injector volume and check spray pattern. Test each fuel injector 2-3 times. Replace fuel injector if volume is not as specified. See «FUEL INJECTOR VOLUME SPECIFICATIONS»(ref-21358-S32091649382001010300000) table. NOTE: Ensure difference between fuel injector volume on all fuel injectors is within specification. See FUEL INJECTOR VOLUME SPECIFICATIONS table.
6. Disconnect fuel injector tester. Ensure fuel leakage from end of fuel injector is one drop or less in specified time. See «FUEL INJECTOR LEAKAGE SPECIFICATIONS»(ref-21358-S34217652432001010300000) table. Replace fuel injector if leakage exceeds specified amount. Turn ignition off and remove test equipment.

FUEL INJECTOR RESISTANCE SPECIFICATIONS

FUEL INJECTOR VOLUME SPECIFICATIONS

FUEL INJECTOR LEAKAGE SPECIFICATIONS

Scheme 45

Scheme 46

Note. Fuel pressure control system may also be referred to as fuel pressure-up system.

Fuel Pressure Control System (Non-Turbo CA & Turbo)

1. Fuel pressure control system uses a fuel pressure control Vacuum Switching Valve (VSV). Fuel pressure control VSV is supplied voltage through EFI main relay.
2. Engine Control Module (ECM) will activate VSV by controlling ground circuit for approximately 90 seconds when restarting engine at normal operating temperature. Locate and remove fuel pressure control VSV. See «FUEL PRESSURE CONTROL VSV LOCATION»(ref-21358-S41863558742001010300000) table. NOTE: Fuel pressure control VSV may also be identified using appropriate illustration in «THEORY/OPERATION»(ref-21401) article or wire color. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-21402) article. FUEL PRESSURE CONTROL VSV LOCATION Application Location Non-Turbo Calif. Driver's Side Of Engine, Near Front Corner Of Intake Manifold Turbo Driver's Side Of Engine, Near Valve Cover & Throttle Cable Bracket
3. Using ohmmeter, check resistance and for continuity between fuel pressure control VSV electrical terminals. Replace fuel pressure control VSV if no continuity exists or resistance is not within specification. See «FUEL PRESSURE CONTROL VSV RESISTANCE SPECIFICATIONS»(ref-21358-S23689129792001010300000) table.
4. Ensure no continuity exists between each electrical terminal and fuel pressure control VSV body. Replace fuel pressure control VSV if continuity exists between electrical connector and fuel pressure control VSV body.
5. Check fuel pressure control VSV operation by applying air pressure to designated area and checking air passage, and then applying battery voltage and ground and retesting. (Scheme 47) Replace fuel pressure control VSV if defective.

FUEL PRESSURE CONTROL VSV RESISTANCE SPECIFICATIONS

Scheme 47

Fuel Cut System

1. Install tachometer. Tachometer must be connected to proper terminals. See IDLE SPEED & MIXTURE in «ADJUSTMENTS»(ref-21357) article. CAUTION: Some tachometers may not be compatible with ignition system. Consult tachometer manufacturer before connecting tachometer to system. To avoid possible damage to ignitor and/or coil, DO NOT allow tachometer terminal to become grounded.
2. Start engine and warm to normal operating temperature. Ensure all accessories are off. Gradually increase engine RPM to maintain at least specified engine speed. See «FUEL CUT SYSTEM TESTING SPECIFICATION»(ref-21358-S06672316152001010300000) table. FUEL CUT SYSTEM TESTING SPECIFICATION Application Engine RPM Supra 3000
3. Using stethoscope, check for fuel injector operating sound. Ensure when throttle lever is released, fuel injector stops operating momentarily (fuel cut RPM) and then resumes operating (fuel return RPM).
4. Ensure fuel cut RPM (if available) and fuel return RPM are within specification. See «FUEL CUT SYSTEM SPECIFICATIONS»(ref-21358-S38979187412001010300000) table. Shut engine off. Disconnect tachometer.

FUEL CUT SYSTEM SPECIFICATIONS (1)

IDLE AIR CONTROL (IAC) VALVE

1. Listen for clicking sound at IAC valve immediately after engine is shut off. NOTE: On Turbo models, IAC valve is located on air intake chamber, near throttle body. On Non-Turbo, IAC valve is located on throttle body.
2. If no clicking sound is heard, check IAC valve resistance and operation. To check IAC valve resistance, ensure ignition is off. Disconnect electrical connector from IAC valve. Note IAC valve terminals. (Scheme 48)and (Scheme 49).
3. Using ohmmeter, measure resistance between specified terminals. See «IAC VALVE RESISTANCE SPECIFICATIONS»(ref-21358-S24963290122001010300000) table. Replace IAC valve if resistance is not within specification. IAC VALVE RESISTANCE SPECIFICATIONS Terminals Ohms Non-Turbo B1 To All Other Terminals 18-22 B2 To All Other Terminals 18-22 Turbo B1 To All Other Terminals 18-24 B2 To All Other Terminals 18-24
4. To check IAC valve operation, remove IAC valve. Note IAC valve terminal identification. (Scheme 48)and (Scheme 49).
5. Apply battery voltage to terminals B1 and B2. (Scheme 48)and (Scheme 49). Repeatedly ground terminals in sequence and ensure IAC valve closes and opens. See «IAC VALVE GROUNDING SEQUENCE»(ref-21358-S37405651192001010300000) table. (Scheme 50)and (Scheme 51). Replace IAC valve if defective. IAC VALVE GROUNDING SEQUENCE Application Terminal Grounding Sequence To Close IAC Valve S1-S2-S3-S4-S1 To Open IAC Valve S4-S3-S2-S1-S4
6. If IAC valve resistance is correct and operates correctly, check wiring between Engine Control Module (ECM) and IAC valve. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-21402) article.
7. ECM is located below passenger's side of dash, underneath carpet on the floor.

Scheme 48

Scheme 49

Scheme 50

Scheme 51

IGNITION SYSTEM

Note. For basic ignition checks, see BASIC TESTING article.

See KNOCK SENSOR under ENGINE SENSORS & SWITCHES .

1. Disconnect vacuum hoses from EGR vacuum modulator. Plug one end of vacuum hose connection on EGR vacuum modulator.
2. Apply air pressure through remaining port. Air should pass freely through air filter side of EGR vacuum modulator.
3. Start and operate engine at specified RPM. See «EGR VACUUM MODULATOR TESTING SPECIFICATIONS»(ref-21358-S20729121462001010300000) table. Repeat test procedures in steps 1) and 2). Strong resistance of airflow should be felt. Replace EGR vacuum modulator if resistance is not felt. Reconnect vacuum hoses to proper locations.

1. Mark locations and disconnect vacuum hoses from EGR vacuum modulator. Block ports "P" and "R" of EGR vacuum modulator. see scheme 43 NOTE: Ports "P" and "R" are the double ports on side of EGR vacuum modulator. Port "Q" is the single port on side of EGR vacuum modulator.
2. Apply air pressure to port "Q". see scheme 43 Air should pass freely through air filter side of EGR vacuum modulator.
3. Start and operate engine at specified RPM. See «EGR VACUUM MODULATOR TESTING SPECIFICATIONS»(ref-21358-S20729121462001010300000) table. Repeat test procedures in steps 1) and 2). Strong resistance of airflow should be felt. Replace EGR vacuum modulator if resistance is not felt. Reconnect vacuum hoses to proper locations.

EGR VACUUM MODULATOR TESTING SPECIFICATIONS

EGR VACUUM SWITCHING VALVE (VSV)

Note. When testing EGR VSV, use proper illustration to determine component location. (Scheme 52)-50. The EGR VSV may be referred to as the VSV.

1. Disconnect electrical connector from EGR VSV. Using ohmmeter, check resistance between EGR VSV electrical terminals.
2. Replace EGR VSV if resistance is not within specification. See «EGR VSV RESISTANCE SPECIFICATIONS»(ref-21358-S33729807482001010300000) table. Check that no continuity exists between each electrical terminal and EGR VSV body. Replace EGR VSV if continuity exists between any electrical terminal and VSV body.
3. Apply air pressure to port "E" (without battery connected). (Scheme 52) Air pressure should not flow through port "F". Connect battery voltage and ground to EGR VSV electrical terminals. (Scheme 52) Apply air pressure to port "E". Air pressure should flow from port "F". Replace EGR VSV if defective.

EGR VSV RESISTANCE SPECIFICATIONS

Scheme 52

Scheme 53

Scheme 54

Scheme 55

Scheme 56

Scheme 57

Scheme 58

Scheme 59

Scheme 60

Scheme 61

Scheme 62

Note. The EVAP Thermal Vacuum Valve (TVV) may be referred to as EVAP Thermal Valve (TV).

Charcoal Canister (Non-Turbo)

1. Disconnect hoses from charcoal canister. Check for clogged filter and/or stuck check valve by applying low air pressure to port "A". (Scheme 63)and (Scheme 64). Ensure air flows freely from other ports on charcoal canister.
2. Apply low air pressure to port "B". (Scheme 63)and (Scheme 64). Ensure no air flows from any other ports on charcoal canister. Replace charcoal canister if defective.
3. To clean charcoal canister filter, apply 43 psi (3 kg/cm 2 ) air pressure to port "A" while holding port "B" closed. Ensure no activated carbon comes out of charcoal canister. DO NOT attempt to wash out charcoal canister.

Charcoal Canister (Turbo)

1. Disconnect hoses from charcoal canister. Check for clogged filter and/or stuck check valve by applying low air pressure to port "A". (Scheme 63)and (Scheme 64). Ensure air flows freely from other ports on charcoal canister.
2. Apply low air pressure to port "B". (Scheme 63)and (Scheme 64). Ensure no air flows from any other ports on charcoal canister. Apply low air pressure to port "C". (Scheme 63)and (Scheme 64). Ensure no air flows from any other ports on charcoal canister. Replace charcoal canister if defective.
3. To clean charcoal canister filter, apply 43 psi (3 kg/cm 2 ) air pressure to port "A" while holding ports "B" and "C" closed. Ensure no activated carbon comes out of charcoal canister. DO NOT attempt to wash out charcoal canister.

Scheme 63

Scheme 64

Check Valve

1. Remove check valve from vacuum hose. (Scheme 59)-54. Apply air pressure to Blue side of check valve. Air should pass through check valve.
2. Apply air pressure to Black side of check valve. Air should not pass through check valve. Replace check valve if defective.

EVAP Vacuum Switching Valve

1. Remove EVAP Vacuum Switching Valve (VSV). See «EVAP VSV LOCATIONS»(ref-21358-S01998376812001010300000) table. EVAP VSV LOCATIONS Application Location Supra Lower Rear Corner Of Intake Manifold NOTE: EVAP VSV may also be identified by wire colors. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-21402) article. EVAP VSV may also be identified using appropriate illustration in «THEORY/OPERATION»(ref-21401) article.
2. Using ohmmeter, ensure continuity exists between electrical terminals on VSV and resistance is within specification. See «EVAP VSV RESISTANCE SPECIFICATIONS»(ref-21358-S25200754902001010300000) table. EVAP VSV RESISTANCE SPECIFICATIONS Application Ohms @ 68°F (20°C) Non-Turbo 27-33 Turbo 30-34
3. Ensure no continuity exists between each electrical terminal and the body of the VSV. Apply air pressure to port "E". Ensure no air passes out port "F". Perform STEP 1. (Scheme 65)
4. Connect battery voltage and ground to VSV terminals. Apply air pressure to port "E". Ensure air passes out port "F". Perform STEP 2. (Scheme 65) Replace VSV if defective.

Scheme 65

POSITIVE CRANKCASE VENTILATION (PCV)

1. Remove PCV valve. Attach hose to PCV valve. Blow air from cylinder head side of PCV valve. Ensure air passes easily through PCV valve.
2. Blow air from intake manifold side of PCV valve. Ensure air passes through PCV valve with some restriction. Replace PCV valve if valve does not function as described.

THROTTLE CONTROLS

Note. When testing throttle control systems, tachometer may be required. Ensure tachometer is connected to proper terminals. For tachometer connections, see IDLE SPEED & MIXTURE in ADJUSTMENTS article.

1. Warm engine to normal operating temperature. Ensure idle speed is correct. See IDLE SPEED & MIXTURE in «ADJUSTMENTS»(ref-21357) article.
2. Disconnect control cables from throttle body. With engine idling, use screwdriver to push dashpot rod to fully extended position. Note engine speed with dashpot rod fully extended.
3. Engine speed should be 1400-2200 RPM on A/T models or 2200-3000 RPM on M/T models. If engine speed is not within specification, rotate dashpot adjusting screw until proper RPM is obtained. (Scheme 68) Reconnect control cables to throttle body.
4. To check throttle body Vacuum Transmitting Valve (VTV) operation, operate engine at 3500 RPM. Release throttle. Ensure engine returns to idle in a few seconds.

1. Warm engine to normal operating temperature. Ensure idle speed is correct. See IDLE SPEED & MIXTURE in «ADJUSTMENTS»(ref-21357) article.
2. Disconnect control cables from throttle body. With engine idling, rotate throttle linkage on throttle body until dashpot adjusting screw starts to separate from push rod on dashpot. Note engine speed at this position.
3. Engine speed should be 1900-2700 RPM. If engine speed is not as specified, rotate dashpot adjusting screw until specified engine speed is obtained. Reconnect control cables to throttle body.
4. To check throttle body Vacuum Transmitting Valve (VTV) operation, operate engine at 3500 RPM. Release throttle. Ensure engine returns to idle in a few seconds.

Scheme 66

Scheme 67

Scheme 68

1. Warm engine to normal operating temperature. Ensure idle speed is correct. See IDLE SPEED & MIXTURE in «ADJUSTMENTS»(ref-21357) article.
2. Disconnect and plug vacuum hose at throttle opener, located on side of throttle body. Start engine. Maintain engine speed at 2500 RPM. Release throttle and note engine speed. Engine speed should be within specification. See «THROTTLE OPENER SPECIFICATIONS»(ref-21358-S35056549862001010300000) table.
3. If engine speed is not within specification, rotate throttle opener adjusting screw until correct engine speed is obtained. (Scheme 69) Reinstall vacuum hose on throttle opener.

Scheme 69

1. Warm engine to normal operating temperature. Ensure idle speed is correct. See IDLE SPEED & MIXTURE in «ADJUSTMENTS»(ref-21357) article.
2. Disconnect and plug vacuum hose at throttle opener, located on side of throttle body. Start engine. Maintain engine speed at 2500 RPM. Release throttle and note engine speed. Engine speed should be within specification. See «THROTTLE OPENER SPECIFICATIONS»(ref-21358-S35056549862001010300000) table.
3. Replace throttle body if engine speed is not within specification. Reinstall vacuum hose on throttle opener. Start engine and ensure engine returns to correct idle speed.

THROTTLE OPENER SPECIFICATIONS