Engine Controls - System & Component Testing: Other Lexus LX J100

ELECTRONIC THROTTLE CONTROL SYSTEM (ETCS)

Note. The ETCS may also be referred to as Electronic Throttle Control System-Intelligent (ETCS-I or ETCS-i).

For testing of throttle body and components, see THROTTLE BODY under IDLE CONTROL SYSTEM.

Power & Ground Circuits

For testing of Engine Control Module (ECM) power and ground circuits, see PIN VOLTAGE CHARTS article. ECM is located behind glove box.

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 SELF-DIAGNOSTICS - INTRODUCTION article.

ECM POWER SOURCE CIRCUIT (IGNITION KEYED)

STARTER SIGNAL CIRCUIT

ACCELERATOR PEDAL POSITION SENSOR

For testing of accelerator pedal position sensor, see THROTTLE BODY under IDLE CONTROL SYSTEM.

AIRFLOW METER

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

Scheme 48

Scheme 49

1. Turn ignition off. Disconnect electrical connector at airflow meter. Airflow meter is bolted to top side of air intake hose, near upper cap on air cleaner assembly. Remove airflow meter and note airflow meter terminal identification. (Scheme 48)
2. Using ohmmeter, check resistance between terminals E2 and THA. Resistance should be within specification in relation to the temperature. See «AIRFLOW METER RESISTANCE»(ref-2786-S40923865892000041300000) table. Replace airflow meter if resistance is not within specification.
3. To test 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 49)
4. Turn ignition on. Apply air into airflow meter and note voltage reading. (Scheme 49) While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate. Remove voltmeter. Reinstall airflow meter.

AIRFLOW METER RESISTANCE

Scheme 50

1. Disconnect electrical connector at brakelight switch. Brakelight switch is located near top of brake pedal. Note terminal identification on the brakelight switch. (Scheme 50)
2. Using ohmmeter, check that continuity exists between terminals No. 1 and 2 with brake pedal depressed. Check that no continuity exists between terminals No. 1 and 2 with brake pedal released.
3. Check that no continuity exists between terminals No. 3 and 4 with brake pedal depressed. Check that continuity exists between terminals No. 3 and 4 with brake pedal released. Adjust or replace brakelight switch if operation is not as described.

CAMSHAFT POSITION SENSOR

Remove engine cover. Locate Camshaft Position (CMP) sensor. Sensor is mounted to front of left upper (No. 3) timing belt cover. 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 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. ECT sensor is located on passenger's side of coolant pipe at front of engine, in front of intake manifold and contains a Green 2-Pin connector with Green/Black and Brown/White wires. Manufacturer recommends removing throttle body for access to ECT sensor. See THROTTLE BODY under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Remove ECT sensor.
2. Place probe end of ECT sensor and thermometer in container of water. Attach ohmmeter between electrical terminals on ECT sensor. Heat water and note that resistance is within specification in relation to temperature. (Scheme 51) Replace ECT sensor if resistance is not within specification.
3. Using NEW gasket, install ECT sensor. Tighten ECT sensor to 15 ft. lbs. (20 N.m). Install throttle body. Fill cooling system.

Scheme 51

FUEL PUMP SWITCH

For testing of fuel pump switch, see FUEL PUMP SWITCH under FUEL DELIVERY.

Scheme 52

1. Four heated oxygen sensors are used, one on each exhaust manifold, and one on each exhaust pipe, behind catalytic converter. On driver's side, heated oxygen sensor on exhaust manifold may be referred to as bank No. 1 sensor No. 1, and heated oxygen sensor on exhaust pipe behind catalytic converter may be referred to as bank No. 1 sensor No. 2. On passenger's side, heated oxygen sensor on exhaust manifold may be referred to as bank No. 2 sensor No. 1, and heated oxygen sensor on exhaust pipe behind catalytic converter may be referred to as bank No. 2 sensor No. 2.
2. To test heater on heated oxygen sensor, disconnect electrical connector at appropriate heated oxygen sensor and note heated oxygen sensor terminals. (Scheme 52)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 52) Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C).
4. If problem exists in heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). Retrieve DTCs and perform appropriate diagnostic test. See SELF-DIAGNOSTICS - INTRODUCTION article.

INTAKE AIR TEMPERATURE (IAT) SENSOR

IAT sensor is part of airflow meter. To test IAT sensor, see AIRFLOW METER test.

KNOCK SENSORS

1. Knock sensors No. 1 and 2 are located below intake manifold on cylinder block. (Scheme 53) Remove intake manifolds for access to knock sensor. See KNOCK SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION article for removal of intake manifolds.
2. Disconnect electrical connector at knock sensor. Using ohmmeter, check that no continuity exists between electrical terminal on knock sensor and body of knock sensor. Replace knock sensor if continuity exists.

Scheme 53

A/T Models

1. Disconnect electrical connector at Park/Neutral Position (PNP) switch. PNP switch is mounted on side of transmission. Note terminal identification. (Scheme 54)
2. Using ohmmeter, check for continuity between specified terminals with shift lever in proper positions. See «PARK/NEUTRAL POSITION SWITCH SPECIFICATIONS»(ref-2786-S14161826942000041300000) table. If proper continuity cannot obtained, adjust or replace PNP switch as necessary.

PARK/NEUTRAL POSITION SWITCH SPECIFICATIONS

Scheme 54

THROTTLE CONTROL MOTOR

For testing of throttle control motor, see THROTTLE BODY under IDLE CONTROL SYSTEM.

THROTTLE POSITION SENSOR

For testing of throttle position sensor, see THROTTLE BODY under IDLE CONTROL SYSTEM.

VAPOR PRESSURE SENSOR

For testing of vapor pressure sensor, see VAPOR PRESSURE SENSOR under FUEL EVAPORATIVE SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS.

VEHICLE SPEED SENSOR

If a VSS circuit vault is present, a Diagnostic Trouble Code (DTC) should set. Retrieve DTCs and perform appropriate diagnostic test. See SELF-DIAGNOSTICS - INTRODUCTION article.

FUEL PUMP ELECTRONIC CONTROL UNIT

See FUEL PUMP ELECTRONIC CONTROL UNIT under FUEL DELIVERY.

For testing of throttle control motor, see THROTTLE BODY under IDLE CONTROL SYSTEM.

EFI MAIN RELAY

1. Ensure ignition is off. Remove EFI main relay from relay box at driver's side front corner of engine compartment, near battery.
2. To test EFI main relay continuity, use ohmmeter to check for continuity and no continuity between specified terminals on EFI main relay. (Scheme 55)
3. To test EFI main relay operation, apply battery voltage and ground to EFI relay and use ohmmeter to check continuity between specified terminals on EFI main relay. (Scheme 55) Replace EFI main relay if defective.

Scheme 55

See EFI MAIN RELAY under MOTORS & RELAYS.

Fuel pump Electronic Control Unit (ECU) is located behind inner panel, just behind driver's side rear wheelwell. (Scheme 56) Testing information is not available from manufacturer. If problem exists with fuel pump ECU or wiring circuit, a Diagnostic Trouble Code (DTC) P1200 will be stored in Engine Control Module (ECM). Retrieve DTCs and perform appropriate diagnostic test. See SELF-DIAGNOSTICS - INTRODUCTION article.

Scheme 56

Note. Fuel pump switch may also be referred to as fuel pump inertia switch or fuel pump control switch.

1. Fuel pump switch is located on driver's side, under front carpet, next to front console box and contains a reset switch. (Scheme 57) Disconnect electrical connector at fuel pump switch. It will may be necessary to remove carpet and fuel pump switch to access to electrical connector.
2. Using ohmmeter, check that no continuity exists between electrical terminals on fuel pump switch with reset switch in OFF position. Check that continuity exists between electrical terminals on fuel pump switch with reset switch in ON position. Replace fuel pump switch if defective. Ensure reset switch is in the ON position for fuel pump operation.

Scheme 57

Fuel Pump Pressure

For fuel pump pressure testing, see 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 SELF-DIAGNOSTICS - INTRODUCTION article.

Fuel Injector Resistance

Remove engine cover. Turn ignition off. Remove air intake hose with intake air connector located between throttle body and air cleaner assembly. 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 at 68°F (20°C), replace injector.

Scheme 58

Scheme 59

1. To check fuel injector volume, remove fuel injector. See FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Fuel injector is connected to fuel filter and fuel pressure regulator for checking fuel injector volume. Ensure area around fuel filter and fuel inlet hose at end of fuel filter is clean. (Scheme 58) CAUTION: Use care when disconnecting fuel inlet hose from end of fuel filter, as some residual fuel pressure may still exist in the fuel system.
2. Depress both sides of retainer and pull fuel inlet hose with disconnect fitting from fuel filter. (Scheme 58) Purchase NEW fuel inlet hose Part No. (23271-50150) from parts department. Remove fuel pipe connector from end of NEW fuel inlet hose. (Scheme 59)
3. Install delivery hose from Fuel Injector Measuring Kit (SST 09268-41047) with fuel pipe connector on fuel filter. (Scheme 59) Ensure delivery hose and fuel pipe connector are properly connected on fuel filter.
4. Remove fuel pressure regulator from fuel rail. Using NEW "O" ring, install Union (SST 09268-41091) from fuel injector measuring kit on fuel pressure regulator. (Scheme 59) Tighten bolts to 66 INCH lbs. (7.5 N.m). Connect delivery hose to union and fuel return hose to fuel pressure regulator.
5. Check that "O" ring is installed on top of fuel injector. Using Adapter (SST 09268-41110) and Clamp (SST 09268-41300) from fuel injector measuring kit, connect fuel injector to delivery hose. (Scheme 59) Place fuel injector into a clean graduated container. Place vinyl tube on end of fuel injector to prevent fuel spillage.
6. Connect scan tool to data link connector No. 3. see scheme 2 Turn ignition on. Turn scan tool on. Select ACTIVE TEST MODE on scan tool. Using scan tool manufacturer's instructions, activate fuel pump. NOTE: Fuel pump may also be operated to pressurize fuel system by applying battery voltage to electrical terminals on fuel pump. For operating of fuel pump, see «FUEL PUMP RESISTANCE & OPERATION»(ref-2786-S26873529762000041300000) under FUEL DELIVERY.
7. Connect Fuel Injector Tester (09842-30070) to fuel injector for 15 seconds. (Scheme 59) Measure fuel injector volume. Test each fuel injector 2-3 times. Replace fuel injector if fuel injector volume is not within specification. See «FUEL INJECTOR VOLUME SPECIFICATIONS»(ref-2786-S34457223742000041300000) table. Ensure difference between fuel injector volume on all fuel injectors is within specification. See «FUEL INJECTOR VOLUME SPECIFICATIONS»(ref-2786-S34457223742000041300000) table.
8. Disconnect fuel injector tester. Ensure fuel leakage from end of fuel injector does not exceed one drop within 12 minutes. Replace fuel injector if leakage exceeds specification. Disconnect negative battery cable. Remove test equipment.
9. Apply light coat of engine oil on tip of pipe on fuel filter to allow for ease of disconnect fitting and fuel inlet hose installation. CAUTION: DO NOT reuse old retainer when installing fuel inlet hose on fuel filter. Always use a NEW retainer.
10. Using NEW retainer, install fuel inlet hose on fuel filter until "click" sound is heard. DO NOT reuse the old retainer. Pull on fuel inlet hose to ensure fuel pipe connector is properly locked on the fuel filter.
11. Using NEW "O" ring, install fuel pressure regulator. Tighten fuel pressure regulator bolts to 66 INCH lbs. (7.5 N.m). Install negative battery cable. Check for fuel leaks by using scan tool to energize fuel pump.

FUEL INJECTOR VOLUME SPECIFICATIONS

Fuel Cut System

1. Connect scan tool to data link connector No. 3. see scheme 2 Scan tool is used to read engine RPM. Start engine and warm engine to normal operating temperature. Ensure A/C is off. Gradually increase engine to 2500 RPM
2. Using stethoscope, check for fuel injector operating sound. Ensure when throttle lever is released, fuel injector stops operating momentarily and then resumes operating (fuel return RPM). Ensure fuel return RPM is 1000 RPM. Shut engine off. Remove scan tool.

THROTTLE BODY

Note. Electronic Throttle Control System (ETCS) is used for controlling idle speed. ETCS consists of throttle body, accelerator pedal position sensor, Throttle Position (TP) sensor, throttle control motor, magnetic clutch and Engine Control Module (ECM).

Scheme 60

Scheme 61

Scheme 62

Scheme 63

Scheme 64

1. Remove engine cover. Ensure throttle cable and throttle lever on throttle body move smoothly. Note location of throttle control motor on throttle body. (Scheme 60)
2. To check throttle control motor operation, turn ignition on. Rotate throttle lever on throttle body to full throttle while listing for operating sound at throttle control motor and that no grinding noise is heard at throttle control motor and throttle body. Throttle lever will also rotate accelerator pedal position sensor.
3. If throttle control motor operating sound is heard, go to next step. If throttle control motor operating sound is not heard, throttle control motor, wiring harness or Engine Control Motor (ECM) may be defective. ECM is located behind glove box. Go to step 12 for testing of throttle control motor.
4. To test operation of accelerator pedal position sensor, scan tool may be used or voltmeter may be used. If using scan tool, go to next step. If using voltmeter, go to step 8.
5. Connect scan tool to data link connector No. 3. see scheme 2 Scan tool is used to read throttle valve opening which is displayed as a percentage. Ensure Malfunction Indicator Light (MIL) on instrument panel is not illuminated. If MIL is not illuminated, go to next step. If MIL is illuminated, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). Retrieve DTCs and perform appropriate diagnostic test. See SELF-DIAGNOSTICS - INTRODUCTION article.
6. Rotate throttle lever on throttle body to full throttle while reading throttle valve opening on scan tool which is accessed by THROTTLE POS under CURRENT DATA. Throttle lever will also rotate accelerator pedal position sensor. Throttle valve opening should be at least 60 percent.
7. If throttle valve opening is at least 60 percent, go to step 10. If throttle valve opening is not at least 60 percent, problem may exist in accelerator pedal position sensor, wiring circuit or ECM. Go to step 15 for testing of accelerator pedal position sensor.
8. Access ECM behind glove box. Ensure ignition is turned on. Using voltmeter, check voltage between ECM terminals VPA (Red wire) and E2 (Brown/White wire) with accelerator pedal released and with accelerator pedal fully depressed. (Scheme 61)
9. Voltage should be.3-.9 volt with accelerator pedal released and 3.2-4.8 volts with accelerator pedal fully depressed. If voltage is within specification, go to next step. If voltage is not within specification, problem may exist in accelerator pedal position sensor, wiring circuit or ECM. Go to step 15 for testing of accelerator pedal position sensor.
10. Start engine and allow engine to idle. Check operation of Malfunction Indicator Light (MIL) on instrument panel. If MIL is not illuminated, go to next step. If MIL is illuminated, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). Retrieve DTCs and perform appropriate diagnostic test. See SELF-DIAGNOSTICS - INTRODUCTION article.
11. To test operation of air assist system, allow engine to warm to normal operating temperature. Apply parking brake. Place transmission in Neutral. Ensure A/C is off. Note engine idle speed. Engine idle speed should be 650-750 RPM. If all previous steps have been performed, drive vehicle to verify proper operation of throttle body.
12. To test throttle control motor, disconnect electrical connector at throttle control motor. (Scheme 60) Note terminal identification on throttle control motor. (Scheme 62)
13. Using ohmmeter, check resistance between specified terminals on throttle control motor. See «THROTTLE CONTROL MOTOR RESISTANCE»(ref-2786-S24922969182000041300000) table. If resistance is within specification, reinstall electrical connector. Go to next step. If resistance is not within specification, replace throttle control motor. See THROTTLE BODY under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. THROTTLE CONTROL MOTOR RESISTANCE Terminal No. (Circuit) Ohms @ 68°F (20°C) 1 (M+) & 2 (M-).3-100.0 3 (CL-) & 4 (CL+) 4.2-5.2
14. To test TP sensor, disconnect electrical connector at TP sensor. (Scheme 60) Using ohmmeter, check resistance between terminals VC and E2 on TP sensor. (Scheme 63) Replace TP sensor if resistance is not 1250-2350 ohms at 68°F (20°C).
15. To test accelerator pedal position sensor, disconnect electrical connector at accelerator pedal position sensor. (Scheme 60) Using ohmmeter, check resistance between terminals VC and E2 on accelerator pedal position sensor. (Scheme 64) Replace accelerator pedal position sensor if resistance is not 1640-3280 ohms at 68°F (20°C).

IGNITION SYSTEM

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

See KNOCK SENSORS under ENGINE SENSORS & SWITCHES.

Scheme 65

FUEL EVAPORATION SYSTEM

Note. To identify Fuel Evaporative (EVAP) system components (Scheme 65) When testing fuel EVAP system components, it may be necessary to use illustration to determine component location.

Charcoal Canister

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

EVAP Vacuum Switching Valve

1. Remove EVAP Vacuum Switching Valve (VSV). (Scheme 65) Using ohmmeter, measure resistance between EVAP VSV terminals. If resistance is 30-34 ohms at 68°F (20°C), go to next step. If resistance is not 30-34 ohms, replace VSV.
2. Using ohmmeter, ensure no continuity exists between each electrical terminal and body of EVAP VSV. Replace EVAP VSV if continuity exists between electrical terminal and body of EVAP VSV.
3. To test EVAP VSV operation, apply air pressure to port "E". Ensure no air flows from port "F". Perform STEP 1. (Scheme 66)
4. Apply battery voltage and ground to electrical terminals on EVAP VSV. Apply air pressure to port "E". Ensure air flows from port "F". Perform STEP 2. (Scheme 66) Replace EVAP VSV if defective.

Scheme 66

Scheme 67

Scheme 68

1. Ensure ignition is off. To test vapor pressure sensor supply voltage, disconnect electrical connector at vapor pressure sensor. Sensor is located on rear corner of charcoal canister and contains a Black 3-pin connector. (Scheme 65)
2. Turn ignition on. Using voltmeter, measure voltage between terminals VC (Blue/Red wire) and E2 (Brown/White wire) on wiring harness side of electrical connector for vapor pressure sensor. Supply voltage should be 4.5-5.5 volts,.
3. If supply voltage is not within specification, check wiring circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. If supply voltage is within specification, turn ignition off. Reinstall electrical connector on vapor pressure sensor.
4. To test vapor pressure sensor output voltage, turn ignition on. Disconnect vacuum hose from vapor pressure sensor. (Scheme 67)
5. Access Engine Control Module (ECM) behind glove box. Connect voltmeter between terminals E2 (Brown/White wire) and PTNK (Blue/Black wire) at ECM connector. (Scheme 68)
6. Using vacuum pump, apply.59 in. Hg of vacuum to vapor pressure sensor. Output voltage should be 1.3-1.2 volts. Release vacuum from vapor pressure sensor. Output voltage should be 3.0-3.6 volts. Apply.22 psi (.015 kg/cm 2 ) to vapor pressure sensor. Output voltage should be 4.2-4.8 volts. Replace vapor sensor if any output voltage is not as specified. Reconnect vacuum hose.

Vapor Pressure Sensor Vacuum Switching Valve

1. Remove vapor pressure sensor Vacuum Switching Valve (VSV). Vapor pressure sensor VSV is located on charcoal canister and has 3 vacuum ports. (Scheme 65)
2. Using ohmmeter, measure resistance between vapor pressure sensor VSV terminals. If resistance is not 37-44 ohms at 68°F (20°C), replace vapor pressure sensor VSV. If resistance is 37-44 ohms, check for continuity between each VSV electrical terminal and body of vapor pressure sensor VSV. If continuity exists, replace vapor pressure sensor VSV.
3. To test vapor pressure sensor VSV operation, apply air pressure to port "E". Ensure air flows from port "G" and not from port "F". Perform STEP 1. (Scheme 69)
4. Apply battery voltage and ground to electrical terminals on vapor pressure sensor VSV. Apply air pressure to port "E". Ensure air flows from port "F" and not from port "G". Perform STEP 2. (Scheme 69) Replace vapor pressure sensor VSV if defective.

Scheme 69

POSITIVE CRANKCASE VENTILATION (PCV)

Remove PCV valve. PCV valve is located at front of driver's side valve cover, below oil fill cap. Apply air pressure to PCV valve at cylinder head side of PCV valve. Ensure air flows easily through PCV valve. Apply air pressure to PCV valve at intake manifold side of PCV valve. Ensure air flows through PCV valve with some resistance. Replace PCV valve if valve does not function as described.