Engine Controls - System & Component Testing - GS300, IS300, GS430 & LS430: Other Lexus LS III

Intake Air Control Valve

1. Install a 3-way vacuum "T" fitting in vacuum hose between Intake Air Control Valve (IACV) actuator and ACIS Vacuum Switch Valve (VSV). (Scheme 35) Connect a vacuum gauge to vacuum "T" fitting. Start engine. With engine idling, ensure vacuum is not present.
2. Snap accelerator to Wide Open Throttle (WOT). Ensure vacuum reading momentarily reads about 9.8 in. Hg and IACV actuator rod pulls down. If vacuum is not as specified or actuator valve rod fails to pull down, go to next step.
3. Remove IACV. Apply about 15.8 in. Hg to IACV actuator. If IACV actuator rod does not move, turn adjusting screw on IACV assembly. If IACV actuator rod still does not move, replace IACV actuator. If IACV actuator rod moves, check to see if diaphragm holds vacuum for at least one minute. If diaphragm does not hold vacuum, replace IACV actuator. If diaphragm holds vacuum, check vacuum tank. See «ACIS VACUUM TANK»(ref-11558-S29874061292000111700000).

Scheme 35

ACIS Vacuum Tank

1. Disconnect vacuum hoses from vacuum tank. Vacuum tank is located under air intake chamber. (Scheme 35)
2. Apply compressed air to port "A". (Scheme 36) Air should flow out of port "B". Apply compressed air to port "B". Air should not flow from port "A". Plug port "B". Apply 15.8 in. Hg to port "A". Vacuum should hold for at least one minute.
3. If ACIS vacuum tank does not operate as specified, replace ACIS vacuum tank. If ACIS vacuum tank operates as specified, go to next procedure.

Scheme 36

ACIS Vacuum Switching Valve

1. Remove bolt and A/T fluid dipstick and guide. Remove and discard "O" ring. Remove emission control valve set from top of vacuum tank. Disconnect vacuum hoses and electrical connector from ACIS Vacuum Switching Valve (VSV). (Scheme 35)
2. Measure resistance between VSV terminals. If resistance is not 39-45 ohms at 68°F (20°C), replace ACIS VSV. If resistance is 39-45 ohms, check for continuity between VSV case and each terminal at VSV connector (this checks for an internal short). If continuity does not exist, go to next step. If continuity exists, replace VSV.
3. Apply compressed air to port "E". (Scheme 37) Air should flow out of filter, but not out of port "F". Using jumper wires, apply 9-14 volts and ground to VSV terminals. Apply compressed air to port "E". Air should flow out of port "F", but not out of filter. If ACIS VSV does not function as specified, replace ACIS VSV.

Scheme 37

1. Remove throttle body. See THROTTLE BODY under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Remove upper and lower intake manifolds. See KNOCK SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION article. Install a 3-way vacuum "T" fitting in vacuum hose between Intake Air Control Valve (IACV) actuator and ACIS Vacuum Switching Valve (VSV). (Scheme 38) Reinstall intake manifolds and throttle body.
2. Connect a vacuum gauge to vacuum "T" fitting. Start engine. With engine idling, ensure vacuum reading is about 11.8 in. Hg, and IACV actuator rod is pulled out. Snap accelerator to Wide Open Throttle (WOT) position. Vacuum should not exist during WOT and IACV actuator rod should return. If vacuum is not as specified or actuator valve rod fails to pull out, go to next step.
3. Remove IACV. Apply about 11.8 in. Hg to IACV actuator. If IACV actuator rod does not move, replace IACV actuator. If IACV actuator rod moves, check to see if diaphragm holds vacuum for at least one minute. If diaphragm does not hold vacuum, replace actuator. If diaphragm holds vacuum, check vacuum hoses and vacuum tank. See «ACIS VACUUM TANK»(ref-11558-S41883287512000111700000).

Scheme 38

Disconnect vacuum hoses from vacuum tank. Vacuum tank is located under front of intake manifold. Apply compressed air to port "A". (Scheme 39) Air should flow out of port "B". Apply compressed air to port "B". Air should not flow out of port "A". Plug port "B". Apply 11.8 in. Hg of vacuum to port "A". Vacuum should hold for at least one minute. If ACIS vacuum tank does not operate as specified, replace ACIS vacuum tank. If ACIS vacuum tank operates as specified, check vacuum switching valve. See ACIS VACUUM SWITCHING VALVE.

Scheme 39

1. Remove engine cover. Remove air cleaner inlet tube. Remove throttle body. See THROTTLE BODY under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Remove intake manifold assembly. See KNOCK SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION article. Disconnect vacuum hoses and electrical connector from Vacuum Switching Valve (VSV). (Scheme 39) Remove VSV. Measure resistance between VSV terminals. If resistance is 33-39 ohms, go to next step. If resistance is not 33-39 ohms, replace VSV.
2. Check for continuity between VSV case and each terminal at VSV connector (this checks for an internal short). If continuity does not exist, go to next step. If continuity exists, replace VSV.
3. Apply air through VSV port "E". (Scheme 37) Air should flow out of filter, but not out of port "F". Apply 9-14 volts and ground to VSV terminals. Apply compressed air to port "E". Air should flow out of port "F", but not out of filter. If ACIS VSV does not function as specified, replace ACIS VSV.

ECM BACK-UP POWER CIRCUIT (BATTERY)

If circuit or components are faulty, a Diagnostic Trouble Code (DTC) should set. Retrieve DTCs and perform appropriate diagnostic test. See appropriate SELF-DIAGNOSTICS article.

ECM POWER SOURCE CIRCUIT (IGNITION KEYED)

STARTER SIGNAL CIRCUIT

GS300 & IS300

Disconnect accelerator pedal position sensor connector. (Scheme 40) Measure resistance between terminals E2 and VC. If resistance is between 1200-3200 ohms, accelerator pedal position sensor is okay. If resistance is not as specified, replace accelerator pedal position sensor.

Scheme 40

Disconnect accelerator pedal position sensor connector. Sensor is mounted above accelerator pedal. (Scheme 41) Measure resistance between terminals VCP1 and EP1. Also measure resistance between VCP2 and EP2. If resistance is between 1500-6000 ohms on both circuits, accelerator pedal position sensor is okay. If resistance is not as specified, replace accelerator pedal position sensor.

Scheme 41

CAMSHAFT POSITION SENSOR

Remove engine cover. Locate Camshaft Position (CMP) sensor. See CAMSHAFT POSITION SENSOR LOCATION table. Remove intake air connector pipe, if necessary. Disconnect CMP sensor 2-pin connector. Measure resistance between CMP sensor terminals. Replace CMP sensor if resistance is not as specified. See CAMSHAFT POSITION SENSOR RESISTANCE table.

CAMSHAFT POSITION SENSOR LOCATION

CAMSHAFT POSITION SENSOR RESISTANCE

CRANKSHAFT POSITION SENSOR

Crankshaft Position Sensor (CKP) sensor is a pick-up coil that is mounted next to crankshaft pulley. Turn ignition off. Disconnect CKP sensor connector. Measure resistance between CKP sensor terminals. Replace CKP sensor if resistance is not as specified. See CRANKSHAFT POSITION SENSOR RESISTANCE table.

CRANKSHAFT POSITION SENSOR RESISTANCE

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

1. Ensure ignition is off. Locate ECT sensor. See «ENGINE COOLANT TEMPERATURE (ECT) SENSOR LOCATION»(ref-11558-S39451024082000111700000) table. Remove ECT sensor.
2. Place probe end of ECT sensor and thermometer in container of water. Attach ohmmeter between ECT sensor terminals. Heat water and note that resistance is within specification in relation to temperature. (Scheme 42) Replace ECT sensor if resistance is not within specification.
3. Using NEW gasket, install ECT sensor. Tighten ECT sensor to 14 ft. lbs. (19.6 N.m). Fill cooling system.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR LOCATION

Scheme 42

HEATED OXYGEN SENSOR HEATER RESISTANCE

Note. Bank No. 1 refers to bank that includes cylinder No. 1. Bank No. 2 refers to bank without cylinder No. 1. Sensor No. 1 refers to sensor closest to engine block. Sensor No. 2 refers to sensor behind catalytic converter.

1. On GS300 and IS300, locate heated oxygen sensor to be tested. (Scheme 43) Connector for bank No. 2, sensor No. 2 is located under front passenger's seat carpet. On GS430 and LS430, one sensor is located in each exhaust manifold and one sensor is located behind each catalytic converter. Connector for bank No. 1, sensor No. 2 is located behind driver's seat carpet. Connector for bank No. 2, sensor No. 2 is located under front passenger's seat carpet. Go to next step.
2. On all models, disconnect oxygen sensor connector to be tested. Measure resistance between terminals B+ and HT at oxygen sensor connector. (Scheme 44) Replace oxygen sensor if resistance is not 11-16 ohms.

Scheme 43

Scheme 44

IAT Sensor Resistance

On all models, IAT sensor is part of Mass Airflow (MAF) sensor. Turn ignition off. Disconnect MAF sensor connector. Measure resistance between MAF sensor terminals THA and E2. (Scheme 45) Replace MAF sensor if resistance is not as specified. See INTAKE AIR TEMPERATURE (IAT) SENSOR RESISTANCE table.

INTAKE AIR TEMPERATURE (IAT) SENSOR RESISTANCE

Scheme 45

KNOCK SENSOR

Remove knock sensor. See KNOCK SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION article. Check for continuity between knock sensor terminal and knock sensor body (hex portion). If continuity does not exist, knock sensor is okay. If continuity exists, replace knock sensor.

MAF Sensor Resistance

Disconnect MAF sensor connector. Measure resistance between MAF sensor terminals THA and E2 at MAF sensor. (Scheme 45) Resistance should be as specified. See INTAKE AIR TEMPERATURE (IAT) SENSOR RESISTANCE table. If resistance is not as specified, replace MAF sensor.

MAF Sensor Voltage

Leave MAF sensor connector attached. Turn ignition on. Backprobing, connect voltmeter positive lead to terminal VG and negative lead to terminal E2G at MAF sensor connector. (Scheme 46) Blow compressed air through MAF sensor. If voltage does not fluctuate while blowing compressed air through MAF sensor, replace MAF sensor.

Scheme 46

PARK/NEUTRAL POSITION (PNP) SWITCH

1. If PNP switch is out of adjustment, voltage signals may not be correctly applied to ECM, causing a Diagnostic Trouble Code (DTC) to set. Before assuming PNP switch is faulty, adjust PNP switch. See PARK/NEUTRAL POSITION (PNP) SWITCH under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION article.
2. After switch adjustment is completed, recheck for codes. If DTC does not reset, PNP switch is okay. If DTC resets, remove PNP switch. Check for continuity between specified terminals of PNP switch. See «PNP SWITCH CONTINUITY»(ref-11558-S32965130932000111700000) table. (Scheme 47) If continuity is not as specified, replace PNP switch. If continuity is as specified, install and adjust PNP switch.

PNP SWITCH CONTINUITY

Scheme 47

PARK/NEUTRAL POSITION (PNP) SWITCH CIRCUIT

If circuit or component is faulty, a Diagnostic Trouble Code (DTC) should set. Retrieve DTCs and perform appropriate diagnostic test. See appropriate SELF-DIAGNOSTICS article.

Disconnect Throttle Position (TP) sensor connector. Do not confuse TP sensor with accelerator position sensor. Both sensors have 4-pin connectors and are mounted on throttle body (Scheme 48) Measure resistance between terminals E2 and VC at TP sensor. Resistance should be 1200-3200 ohms at 68°F (20°C). If resistance is not 1200-3200 ohms, replace TP sensor.

Scheme 48

Disconnect Throttle Position (TP) sensor 4-pin connector. (Scheme 49) Measure resistance between terminals VC and ETA at TP sensor. Resistance should be 1250-2350 ohms at 68°F (20°C). If resistance is not 1250-2350 ohms, replace TP sensor.

Scheme 49

VAPOR PRESSURE SENSOR

For vapor pressure sensor testing, see appropriate VAPOR PRESSURE SENSOR CIRCUIT test under EMISSION SYSTEMS & SUB-SYSTEMS.

VARIABLE VALVE TIMING SENSOR

Note. GS300 and IS300 models are equipped with variable valve timing but use the camshaft position sensor instead of Variable Valve Timing (VVT) sensors to determine camshaft position. For testing procedure, see CAMSHAFT POSITION SENSOR .

1. Variable Valve Timing (VVT) sensors are located on top of engine and are mounted on the intake side of each cylinder head. To access left VVT sensor, remove engine cover. Disconnect engine wire protector from upper intake manifold and camshaft bearing cap. Disconnect VVT sensor 2-pin connector with Green and Red wires. To access right VVT sensor, remove engine cover. Remove intake air connector pipe. Disconnect VVT sensor 2-pin connector with Yellow and Blue wires.
2. Measure resistance between VVT sensor terminals. Replace sensor if resistance is not as specified. See «VARIABLE VALVE TIMING SENSOR RESISTANCE»(ref-11558-S01741851792000111700000) table.

VARIABLE VALVE TIMING SENSOR RESISTANCE

VEHICLE SPEED SENSOR (VSS)

Remove VSS from rear of transmission. Using an ohmmeter, measure resistance between VSS connector terminals. Resistance should be 560-680 ohms. Using a voltmeter set to AC voltage, measure voltage between VSS connector terminals. Place a magnet close to front of VSS and quickly remove (to generate a voltage pulse). If voltage pulse is not generated, replace VSS.

Throttle Control Motor (GS300 & IS300)

1. Disconnect throttle motor 4-pin connector. Throttle control motor is mounted on side of throttle body. Measure resistance between terminals No. 3 (CL-) and 4 (CL+) at throttle control motor. (Scheme 50) Resistance should be 4.2-5.2 ohms at 68°F (20°C). If resistance is not 4.2-5.2 ohms, replace throttle control motor. If resistance is as specified, go to next step.
2. Measure resistance between terminals No. 1 (M+) and 2 (M-) at throttle control motor connector. (Scheme 50) Resistance should be.3-100.0 ohms at 68°F (20°C). If resistance is not.3-100.0 ohms, replace throttle control motor.

Scheme 50

Throttle Control Motor (LS430 & GS430)

Disconnect throttle motor 2-pin connector. Throttle control motor is mounted on side of throttle body. Measure resistance between terminals No. 1 (M+) and 2 (M-) at throttle control motor connector. (Scheme 51) Resistance should be.3-100 ohms at 68°F (20°C). If resistance is not.3-100 ohms, replace throttle control motor.

Scheme 51

RELAYS

Note. For cooling fan relay testing, see appropriate article in ENGINE COOLING.

ACIS Vacuum Switching Valve (VSV)

See appropriate ACOUSTIC CONTROL INDUCTION SYSTEM (ACIS) test under AIR INDUCTION SYSTEMS .

EVAP Vacuum Switching Valve

See EVAP VACUUM SWITCHING VALVE under EMISSION SYSTEMS & SUB-SYSTEMS.

Fuel Injectors

See FUEL CONTROL under FUEL SYSTEM.

Canister Closed Valve Vacuum Switching Valve

See CANISTER CLOSED VALVE VACUUM SWITCHING VALVE under EMISSION SYSTEMS & SUB-SYSTEMS.

Pressure Switching Valve Vacuum Switching Valve

See PRESSURE SWITCHING VALVE VACUUM SWITCHING VALVE (GS300 & GS430) or PRESSURE SWITCHING VALVE VACUUM SWITCHING VALVE (LS430 & IS300) under EMISSION SYSTEMS & SUB-SYSTEMS.

FUEL DELIVERY

Note. The following procedure is for checking fuel pump operation using battery voltage. To check fuel pump operation using Lexus scan tool, see FUEL PUMP OPERATION under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article.

Fuel Pump Resistance

Remove rear seat cushion. Remove floor service hole cover. Disconnect 5-pin connector from fuel pump and sending unit assembly. Measure resistance between terminals No. 4 and No. 5 at 5-pin fuel pump and sending unit connector. see scheme 26 Replace fuel pump if resistance is not 0.2-3.0 ohms at 68°F (20°C).

Fuel Pump Control Circuit (GS300 & GS430)

1. Check fuel pump operation. See «FUEL PUMP OPERATION (USING BATTERY VOLTAGE)»(ref-11558-S05268016312000111700000). If fuel pump does not operate, go to next step. If fuel pump operates, go to step 6.
2. Remove trunk trim cover from behind rear seat in luggage compartment. Disconnect fuel pump Electronic Control Unit (ECU) 10-pin connector in left side of luggage compartment. Turn ignition on. Measure voltage between ground and terminal No. 10 (Black/Red wire) at fuel pump ECU connector. (Scheme 52) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check for open or short in wiring harness between EFI main relay and fuel pump ECU. See WIRING DIAGRAMS article.
3. With ignition switch turned to START position, measure voltage between terminals No. 5 (White/Black wire) and No. 8 (Black/Blue wire) at fuel pump ECU. (Scheme 52) If voltage is 3.3-4.3 volts, go to step 5. If voltage is not 3.3-4.3 volts, go to next step.
4. Check for open or short in White/Black wire between fuel pump ECU and ground. See WIRING DIAGRAMS article. Repair as necessary. If White/Black wire is okay, check for open or short in Black/Blue wire between fuel pump ECU and ECM. Repair as necessary. If both circuits are okay, replace ECM and retest system.
5. Check fuel pump. See «FUEL PUMP RESISTANCE»(ref-11558-S30462284672000111700000). Replace fuel pump as necessary. If fuel pump is okay, check for an open circuit in wiring harness between fuel pump ECU and fuel pump. See WIRING DIAGRAMS article. Repair as necessary. If wiring is okay, replace fuel pump ECU and retest.
6. Check for an open or short in Black/Red wire between fuel pump ECU and ECM. See WIRING DIAGRAMS article. Repair as necessary. If wiring is okay, replace ECM and retest.

Scheme 52

Fuel Pump Pressure (All Models)

To check fuel pump pressure, see FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article.

Fuel Pressure Regulator (All Models)

All models use a returnless fuel system and are not equipped with a fuel pressure regulator on fuel rail. Fuel pressure regulator is mounted to fuel pump assembly and is located in fuel tank. To check in tank fuel pressure regulator, perform FUEL PRESSURE test under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article.

Fuel Injector Circuit

If circuit or component is faulty, a Diagnostic Trouble Code (DTC) should set. Retrieve DTCs and perform appropriate diagnostic test. See appropriate SELF-DIAGNOSTICS article.

Fuel Injector Resistance

Remove engine cover. Turn ignition off. Disconnect appropriate injector connector. Measure resistance between injector terminals. Resistance should be about 13.4-14.2 ohms at 68°F (20°C). If resistance is not about 13.4-14.2 ohms, replace injector.

Fuel Injector Volume

1. Remove fuel injector. See FUEL SYSTEM under REMOVAL, OVERHAUL & INSTALLATION article. Disconnect fuel inlet hose from main fuel tube. Install Fuel Tube Adapter (09268-52011) to fuel main tube. Connect fuel hose from Injection Measuring Tool Set (09268-41047) to fuel tube adapter. (Scheme 53)
2. Ensure fuel injector "O" ring is installed. Connect fuel injector to fuel hose and install injector retainer clip. (Scheme 53) Attach a piece of vinyl tubing to bottom of fuel injector to prevent fuel splash. Place vinyl tubing into a graduated measuring cylinder.
3. If using a Lexus scan tool, connect scan tool to Data Link Connector (DLC) No. 3. see scheme 10 Turn ignition on. DO NOT start engine. Turn scan tool on. Select ACTIVE TEST mode on scan tool. Using scan tool manufacturer's instructions, activate electric fuel pump, and go to next step. If Lexus scan tool is not available, manually activate fuel pump. See «FUEL PUMP OPERATION (USING BATTERY VOLTAGE)»(ref-11558-S05268016312000111700000) procedure under FUEL DELIVERY, and then go to next step.
4. Connect EFI Inspection Wiring (09842-30070) between fuel injector and a 12-volt battery. Do not apply voltage to fuel injector for more than 15 seconds. Compare measured volume with specified volume. See «FUEL INJECTOR VOLUME SPECIFICATIONS»(ref-11558-S21597401282000111700000) table. Test each injector 2-3 times. Replace fuel injector if fuel injector volume is not within specification.
5. Ensure difference between fuel injector volume on all fuel injectors is within specification. See «FUEL INJECTOR VOLUME SPECIFICATIONS»(ref-11558-S21597401282000111700000) table. Disconnect fuel injector tester. Ensure fuel leakage from end of fuel injector does not exceed one drop within 12 minutes (one minute on LS430). Replace fuel injector if leakage exceeds specification. Disconnect negative battery cable. Remove test equipment and reconnect all components.

FUEL INJECTOR VOLUME SPECIFICATIONS

Scheme 53

IS300 & LS430

Locate fuel pump resistor located under protective cover on driver's side strut tower. Disconnect fuel pump resistor Black 2-pin connector. Measure resistance between resistor terminals. If resistance is not .30-.35 ohm, replace resistor.

1. Connect scan tool to DLC3 to monitor engine RPM. see scheme 10 Remove engine cover. Start and warm engine to operating temperature. Turn A/C off. Use a stethoscope to listen for injector operating noise (or feel for vibration with finger).
2. Increase engine speed to 3000 RPM. Release throttle lever. When throttle lever is released, injectors should stop operating momentarily until engine speed decreases to 1000 RPM. Shut engine off. Remove scan tool.

1. Connect scan tool to DLC3 to monitor engine RPM. see scheme 10 Remove engine cover. Start and warm engine to operating temperature. Turn A/C off. Use a stethoscope to listen for injector operating noise (or feel for vibration with finger).
2. Increase engine speed to 2500 RPM. Release throttle lever. When throttle lever is released, injectors should stop operating momentarily until engine speed decreases to 1400 RPM. Shut engine off. Remove scan tool.

IGNITION SYSTEM

Note. For basic ignition checks, see IGNITION CHECKS in BASIC DIAGNOSTIC PROCEDURES article.

EMISSION SYSTEMS & SUB-SYSTEMS

FUEL EVAPORATION SYSTEM

Note. Fuel EVAP system may also referred to as On-Board Refilling Vapor Recovery (ORVR) system.

Scheme 54

Scheme 55

1. Inspect all EVAP system lines and connections for sharp bends or damage. (Scheme 56)- (Scheme 58). Fuel inlet pipe may also be referred to as fuel filler pipe. Inspect fuel inlet pipe for cracks, damage or fuel leakage. Inspect fuel tank cap for cracks or deformed gasket. Replace components if defective or damaged.
2. Start engine and warm engine to normal operating temperature. Shut engine off. Connect vacuum gauge from EVAP system test kit to EVAP service port. EVAP service port is located in engine compartment, in the purge vacuum hose for EVAP system. (Scheme 56)- (Scheme 58).
3. EVAP Vacuum Switching Valve (VSV) must be operated. If scan tool is available, go to next step. If scan tool is not available, go to step 5.
4. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 10 Start engine. Turn scan tool on. Select ACTIVE TEST MODE on scan tool. Using scan tool manufacturer's instructions, activate EVAP VSV. Go to step 6.
5. Locate EVAP VSV on top of engine. (Scheme 56)- (Scheme 58). Disconnect EVAP VSV 2-pin electrical connector. Using jumper wires, connect battery voltage and ground to EVAP VSV terminals. Start engine. Go to next step.
6. Check vacuum reading on vacuum gauge with engine idling. Vacuum should be.368-19.713 in. Hg for more than 5 seconds. If vacuum is within specification, go to next step. If vacuum reading is not within specification, check for loose or restricted vacuum hose to EVAP service port, or for malfunctioning EVAP VSV. To check EVAP VSV operation, see «EVAP VACUUM SWITCHING VALVE»(ref-11558-S19629342302000111700000).
7. Shut engine off. If using scan tool to operate EVAP VSV, stop operation of EVAP VSV. Remove scan tool. Go to next step. If connecting battery voltage to EVAP VSV to operate EVAP VSV, disconnect jumper wires and reconnect electrical connector on EVAP VSV. Go to next step.
8. Disconnect vacuum gauge from EVAP service port. Connect pressure gauge to EVAP service port. Locate charcoal canister under rear of vehicle near fuel tank. Install hose crimper on charcoal canister air drain hose. (Scheme 56)- (Scheme 58).
9. Apply 13.5-15.5 in.Aq. of pressure to EVAP service port. After 2 minutes of applying the pressure, the pressure should be 7.7-8.8 in.Aq. If pressure is within specification, remove hose crimper and go to next step. If pressure cannot be maintained, remove hose crimper and check for disconnected vacuum hose between EVAP VSV, charcoal canister and fuel tank. If vacuum hose is properly installed on EVAP VSV, charcoal canister and fuel tank, check for stuck open EVAP VSV. To check EVAP VSV operation, see «EVAP VACUUM SWITCHING VALVE»(ref-11558-S19629342302000111700000).
10. With pressure still applied at EVAP service port, remove fuel tank cap and note pressure reading. Pressure should decrease when fuel tank cap is removed. If pressure decreases when fuel tank cap is removed, remove pressure gauge and go to next step. If pressure does not decrease when fuel tank cap is removed, remove pressure gauge and check for restricted vacuum hose between EVAP service port, charcoal canister and fuel tank. Repair or replace vacuum hose as necessary.
11. To check airtightness of fuel tank and fuel inlet pipe, disconnect EVAP line hose from EVAP port at charcoal canister. (Scheme 54) Apply.58 psi (4 kPa) of air pressure to EVAP line hose so pressure inside the fuel tank is.58 psi (.040 kg/cm 2 ). Check that pressure inside fuel tank holds steady for one minute.
12. If pressure inside fuel tank holds steady for one minute, reinstall EVAP line hose on charcoal canister and go to next step. If pressure inside fuel tank will not hold steady for one minute, check for leaking hoses or pipes at fuel tank and fuel inlet pipe, or for leaks at fuel tank or installed components on fuel tank. If no leaks exist, replace fuel tank and fuel inlet pipe. Reinstall EVAP line hose on charcoal canister and go to next step. NOTE: Overfill check valve may also be referred to as fill check valve. Cut-off valve may also be referred to as fuel cut-off valve.
13. To check overfill check valve and cut-off valve, disconnect purge line hose, air drain hose and EVAP line hose from charcoal canister. Install cap on air drain hose port. (Scheme 54)
14. Apply.58 psi (4 kPa) air pressure to purge line hose fitting on charcoal canister. (Scheme 54) Ensure air flows from EVAP line hose when air pressure is applied to purge line hose fitting on charcoal canister. If fuel tank is full of fuel, air may not flow from EVAP line hose, as overfill check valve may be closed. Ensure fuel tank is not full of fuel when checking for airflow at EVAP line hose.
15. If air flows from EVAP line hose, go to next step. If air does not flow from EVAP line hose, check for restrictions in EVAP line hose and vent line hose. If any hose is restricted, replace hose and recheck operation. If hoses are not restricted, replace overfill check valve and cut-off valve located on top of fuel tank. (Scheme 56)- (Scheme 58).
16. Reinstall purge line hose, air drain hose and EVAP line hose on charcoal canister. To check air inlet line, disconnect air inlet line hose from charcoal canister. (Scheme 54) Apply air pressure to air inlet line hose. Air should flow through air inlet line hose. If air flows through air inlet line hose, go to next step. If air does not flow through air inlet line hose, check for restricted air inlet line hose or air inlet line.
17. Disconnect necessary electrical connectors and components for removal of charcoal canister. Disconnect purge line hose, EVAP line hose and air inlet line hose from charcoal canister.
18. Push connector on vent line hose toward charcoal canister and pinch both sides of retainer on connector, and then disconnect vent line hose with connector from charcoal canister. (Scheme 55)
19. Remove charcoal canister and vapor pressure sensor retaining bolts. Remove charcoal canister. Inspect charcoal canister for cracks or damage at all hose fittings. If charcoal canister is okay, go to next step. If charcoal canister is defective, replace charcoal canister.
20. To check charcoal canister, install cap on vent port on charcoal canister. (Scheme 54) Apply.26 psi (1.76 kPa) air pressure to EVAP port while holding purge port closed. Ensure air flows freely from air drain port.
21. Apply.26 psi (.018 kg/cm 2 ) air pressure to EVAP port while holding air drain port and purge port closed. (Scheme 54) Ensure no air flows from air inlet port.
22. Using vacuum pump, apply 1.01 in. Hg (3.43 kPa) of vacuum to purge port. (Scheme 54) Ensure vacuum does not decrease when air inlet port is closed, and that vacuum decreases when air inlet port is opened.
23. While holding air inlet port closed, use vacuum pump to apply 1.01 in. Hg (3.43 kPa) of vacuum to EVAP port. (Scheme 54) Ensure air flows into purge port. Remove cap from vent port. Replace charcoal canister if defective.
24. Reinstall charcoal canister. If fuel EVAP system operates properly, it may be necessary to check operation of EVAP Vacuum Switching Valve (VSV), pressure switching valve VSV, canister closed valve VSV and vapor pressure sensor. See «EVAP VACUUM SWITCHING VALVE»(ref-11558-S19629342302000111700000), «VAPOR PRESSURE SENSOR CIRCUIT»(ref-11558-S36182081272000111700000), «PRESSURE SWITCHING VALVE VACUUM SWITCHING VALVE (GS300 & GS430)»(ref-11558-S15678605482000111700000) or «PRESSURE SWITCHING VALVE VACUUM SWITCHING VALVE (LS430 & IS300)»(ref-11558-S31573187742000111700000).

Scheme 56

Scheme 57

Scheme 58

Charcoal Canister

For testing of charcoal canister, see FUEL EVAP SYSTEM TEST .

1. Remove engine cover. Disconnect EVAP VSV connector. EVAP VSV is located near top of engine. (Scheme 56)- (Scheme 58). Disconnect vacuum hoses from VSV. Remove VSV. Measure resistance between VSV terminals. On GS300 and IS300, resistance should be 27-33 ohms at 68°F (20°C). On GS430 and LS430, resistance should be 30-34ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace VSV.
2. Check for continuity between VSV case and each terminal of VSV connector (this checks for an internal short). If continuity does not exist, go to next step. If continuity exists, replace VSV.
3. Apply compressed air to port "E" (port closest to electrical connector). Air should not flow from port "F" (port farthest away from electrical connector). If VSV function as specified, go to next step. If VSV does not function as specified, replace VSV.
4. Apply battery voltage across VSV terminals. Apply compressed air to port "E". If air flows out of port "F", VSV is functioning properly. If air does not flow out of port "F", replace VSV.

Scheme 59

1. Disconnect vapor pressure sensor connector. Sensor is mounted on EVAP charcoal canister underneath rear of vehicle and has a Black 3-pin connector. (Scheme 56)- (Scheme 58). Turn ignition on. Measure voltage between terminals E2 and VC at vapor pressure sensor connector terminals. (Scheme 59) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, check wiring harness between sensor and ECM. See WIRING DIAGRAMS article. Repair as necessary. If wiring is okay, replace ECM.
2. Turn ignition off. Reconnect vapor pressure sensor connector. Access ECM harness connectors in left front of engine compartment. Disconnect vapor pressure sensor vacuum hose. (Scheme 59) Connect vacuum/pressure pump to vapor pressure sensor. Turn ignition on.
3. Backprobing, measure voltage between following ECM terminals: On GS300, terminals No. 18 (Blue/Yellow wire) at ECM E5 connector and No. 18 (Brown wire) at ECM E3 connector. see scheme 6 On IS300, terminals No. 18 (Pink/Green wire) at ECM E4 connector and No. 18 (Brown wire) at ECM E6 connector. see scheme 7 On GS430, terminals No. 25 (Blue/Yellow wire) at ECM E5 connector and No. 26 (Brown wire) at ECM E5 connector. see scheme 8 On LS430, terminals No. 25 (Light Green/Red wire) at ECM connector E2 and No. 26 (Brown/White wire) at ECM E2 connector. see scheme 9 On all models, voltage reading should be as follows: 3.0-3.6 volts with no vacuum applied. 1.3-2.1 volts with.59 in. Hg (2.0 kPa) of vacuum applied. 4.2-4.8 volts with.22 psi (1.5 kPa) of pressure applied. If voltage is not as specified, replace vapor pressure sensor.

Pressure Switching Valve Vacuum Switching Valve (GS300 & GS430)

1. Remove pressure switching valve Vacuum Switching Valve (VSV). VSV has 3 vacuum ports and is mounted on EVAP canister. (Scheme 56)or (Scheme 57). Measure resistance between pressure switching valve VSV terminals. If resistance is 33-39 ohms at 68°F (20°C), go to next step. If resistance is not 33-39 ohms, replace pressure switching valve VSV.
2. Check for continuity between pressure switching valve VSV case and each terminal of VSV connector (this checks for an internal short). If continuity does not exist, go to next step. If continuity exists, replace pressure switching valve VSV.
3. Apply air pressure to VSV port "E". (Scheme 60) If air flows from port "G", go to next step. If air does not flow from port "G", replace VSV.
4. Using jumper wires, apply battery voltage and ground across pressure switching valve VSV terminals. Apply compressed air to port "E". If air flows out of port "F", VSV is functioning properly. If air does not flow from port "F", replace VSV.

Scheme 60

Pressure Switching Valve Vacuum Switching Valve (LS430 & IS300)

1. Remove pressure switching valve Vacuum Switching Valve (VSV). VSV has 2 vacuum ports, a Blue 2-pin connector and is mounted on EVAP canister. EVAP canister is located underneath rear of vehicle, near fuel tank. Measure resistance between pressure switching valve VSV terminals. If resistance is 37-44 ohms at 68°F (20°C) or 51-62 ohms at 248°F (120°C), go to next step. If resistance is not as specified, replace VSV.
2. Check for continuity between pressure switching valve VSV case and each terminal of VSV connector (this checks for an internal short). If continuity does not exist, go to next step. If continuity exists, replace pressure switching valve VSV.
3. Apply air pressure to VSV port "E". (Scheme 61)- (Scheme 62). If air does not flow from port "F", go to next step. If air flows from port "F", replace VSV.
4. Using jumper wires, apply battery voltage and ground across VSV terminals. Apply compressed air to port "E". If air flows out of port "F", VSV is functioning properly. If air does not flow from port "F", replace VSV.

Scheme 61

Scheme 62

1. Remove canister closed valve Vacuum Switching Valve (VSV). VSV has 2 vacuum ports, a Black (IS300 and GS300) or Gray (GS430 and LS430) 2-pin connector, and is located on rear of air filter housing. Measure resistance between canister closed valve VSV terminals. If resistance is 24-30 ohms at 68°F (20°C), go to next step. If resistance is not 25-30 ohms, replace VSV.
2. Check for continuity between canister closed valve VSV case and each terminal of VSV connector (this checks for an internal short). If continuity does not exist, go to next step. If continuity exists, replace canister closed valve VSV.
3. Apply air pressure to VSV port "A". (Scheme 63)- (Scheme 64). If air flows from port "B", go to next step. If air does not flow from port "B", replace VSV.
4. Using jumper wires, apply battery voltage and ground across VSV terminals. Apply compressed air to port "A". If air does not flow out of port "B", VSV is functioning properly. If air flows from port "B", replace VSV.

Scheme 63

Scheme 64

PCV Valve

Remove PCV valve from valve cover. Inspect PCV hoses, connections and gaskets for leaks and damage. Apply compressed air to cylinder head side of PCV valve. Air should pass freely through PCV valve. Apply compressed air to intake manifold side of PCV valve. Air should not pass freely through PCV valve. Clean or replace PCV valve if air does not flow as specified.

CAMSHAFT TIMING OIL CONTROL VALVE

Note. Camshaft timing oil control valve is also referred to as oil control valve.

Resistance Check (GS300 & IS300)

Oil Control Valve (OCV) is located on top front of valve cover and has a Black 2-pin connector. Disconnect OCV connector. Measure resistance between OCV terminals. Resistance should be 5.5-12.0 ohms at 68°F (20°C). If resistance is not 5.5-12.0 ohms, replace OCV.

Resistance Check (GS430 & LS430)

All models are equipped with 2 Oil Control Valves (OCVs). Each cylinder head has one OCV located in front inside corner of cylinder head. (Scheme 65) Remove engine cover. Remove intake air connector pipe, if necessary. Disconnect Black 2-pin connector from OCV to be tested. Measure resistance between OCV terminals. Resistance should be 6.9-7.9 ohms at 68°F (20°C). If resistance is not 6.9-7.9 ohms, replace OCV.

Scheme 65

VARIABLE VALVE TIMING (VVT) SENSOR

For VVT sensor testing, see VARIABLE VALVE TIMING SENSOR under ENGINE SENSORS & SWITCHES.

THROTTLE BODY

Note. Before performing the following procedure, ensure no Diagnostic Trouble Codes (DTCs) are present. See appropriate SELF-DIAGNOSTICS article. Repair any DTCs that are present before continuing with this test.

MISCELLANEOUS CONTROLS

Note. Although some of the controlled devices listed here are not technically engine performance components, they can affect driveability if they malfunction.

COOLING FAN SYSTEM

For electric cooling fan testing, see SPECIFICATIONS & ELECTRIC COOLING FANS article in ENGINE COOLING.

TRANSMISSION

For transmission diagnostic information, see appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS.