Engine Controls - System/component Tests - 4-CYL: Other Toyota Tercel L50 рестайлинг

Power & Ground Circuits

For testing of Engine Control Module (ECM) power and ground circuits, see appropriate J - PIN VOLTAGE CHARTS article. Refer to ECM LOCATION (TABLE 1) for identifying ECM mounting locations.

ECM LOCATION (TABLE 1)

Camry & RAV4 Calif. Emission Vehicles

1. Heated A/F sensor is mounted on exhaust manifold above catalytic converter. If problem exists in A/F sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in the Engine Control Module (ECM). For diagnosis of DTC, see appropriate G - TESTS W/CODES article.
2. To test the heater resistance on A/F sensor, disconnect electrical connector for A/F sensor. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 63)and (Scheme 64). Replace the A/F sensor if resistance is not.8-1.4 ohms at 68°F (20°C).

Scheme 63

Scheme 64

AIRFLOW METER

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

Scheme 65

Scheme 66

1. Turn ignition off. Disconnect electrical connector from airflow meter. Airflow meter is located between air intake hose and the upper cap on air cleaner assembly. Airflow meter is bolted to the upper cap on air cleaner assembly. Note airflow meter terminal identification. See
2. Using ohmmeter, check resistance between terminals E2 and THA on airflow meter. Resistance should be within specification in relation to the temperature. See «AIRFLOW METER RESISTANCE»(ref-95581-S18344528842001040200000) table. Replace airflow meter if resistance is not within specification. AIRFLOW METER RESISTANCE Temperature Ohms -4°F (-20°C) 10,000-20,000 32°F (0°C) 4000-7000 68°F (20°C) 2000-3000 104°F (40°C) 900-1300 140°F (60°C) 400-700 176°F (80°C) 200-400
3. To test airflow meter operation, remove airflow meter. See appropriate N - REMOVE/INSTALL/OVERHAUL article. Ensure electrical connector is installed on airflow meter. Connect voltmeter leads to proper terminals on airflow meter with electrical connector installed. (Scheme 66)
4. Turn ignition on. Apply air into airflow meter and note voltage reading. (Scheme 66) While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate. Remove voltmeter.

Camry, Corolla, Tacoma, T100 & 4Runner

1. Disconnect electrical connector at brakelight switch. Brakelight switch is located near top of brake pedal. Note terminal identification on the brakelight switch. (Scheme 67)and (Scheme 68).
2. On models without cruise control, use ohmmeter to check that no continuity exists between terminals No. 1 and 2 with brake pedal released. Check that continuity exists between terminals No. 1 and 2 with brake pedal depressed. Adjust or replace brakelight switch if operation is not as described.
3. On models with cruise control, use ohmmeter to check that no continuity exists between terminals No. 1 and 2 with brake pedal released. Check that continuity exists between terminals No. 1 and 2 with brake pedal depressed.
4. 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.

Celica & RAV4

1. Disconnect electrical connector at brakelight switch. Brakelight switch is located near top of brake pedal. Note terminal identification on brakelight switch. (Scheme 68)
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.

Tercel

1. Disconnect electrical connector at brakelight switch. Brakelight switch is located near top of brake pedal. Note terminal identification on brakelight switch. (Scheme 69)
2. Use ohmmeter to check that no continuity exists between terminals No. 1 and 2 with brake pedal released. Check that continuity exists between terminals No. 1 and 2 with brake pedal depressed. Adjust or replace brakelight switch if operation is not as described.

Scheme 67

Scheme 68

Scheme 69

Camry, Corolla, RAV4, Tacoma, Tercel, T100 & 4Runner

For testing camshaft position sensor, CAMSHAFT POSITION SENSOR RESISTANCE under IGNITION CHECKS (DISTRIBUTORLESS IGNITION SYSTEM) in appropriate F - BASIC TESTING article.

Celica

Camshaft position sensor is a pick-up coil located in the distributor. For checking of pick-up coil, see PICK-UP COIL RESISTANCE and PICK-UP COIL AIR GAP under IGNITION CHECKS (DISTRIBUTOR TYPE IGNITION SYSTEM) in appropriate F - BASIC TESTING article.

For testing crankshaft position sensor, see CRANKSHAFT POSITION SENSOR RESISTANCE under IGNITION CHECKS (DISTRIBUTORLESS IGNITION SYSTEM) in appropriate F - BASIC TESTING article.

For testing crankshaft position sensor, see CRANKSHAFT POSITION SENSOR RESISTANCE under IGNITION CHECKS (DISTRIBUTOR TYPE IGNITION SYSTEM) in appropriate F - BASIC TESTING article.

Tacoma, T100 & 4Runner

1. EGR gas temperature sensor is located near EGR valve. Remove EGR gas temperature sensor. See appropriate N - REMOVE/INSTALL/OVERHAUL article.
2. Place threaded end of EGR gas temperature sensor and thermometer in container of oil. Attach ohmmeter between electrical terminals on EGR gas temperature sensor.
3. Heat oil and note resistance at specified temperature. See «EGR GAS TEMPERATURE SENSOR RESISTANCE»(ref-95581-S08457629382001040200000) table. Replace EGR gas temperature sensor if resistance is not within specification. Reinstall EGR gas temperature sensor.

EGR GAS TEMPERATURE SENSOR RESISTANCE

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

1. Ensure ignition is off. Disconnect electrical connector from ECT sensor. See «ENGINE COOLANT TEMPERATURE (ECT) SENSOR LOCATION»(ref-95581-S40372627632004022300000) table. Remove ECT sensor. See appropriate N - REMOVE/INSTALL/OVERHAUL article.
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 70) Replace ECT sensor if resistance is not within specification.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR LOCATION

Scheme 70

HEATED OXYGEN SENSOR

See OXYGEN SENSOR .

Camry, Celica, Corolla, RAV4 & Tercel

1. Ensure ignition is off. Disconnect electrical connector from intake air temperature sensor located on top cover of air filter housing.
2. Remove intake air temperature sensor. Place probe end of intake air temperature sensor and thermometer in container of water. Attach ohmmeter between the electrical terminals on intake air temperature sensor.
3. Heat water and note that resistance is within specification in relation to temperature. (Scheme 70) Replace intake air temperature sensor if resistance is not within specification.

KNOCK SENSOR

Note. Knock Sensor (KS) may also be referred to as knock sensor No. 1.

1. KS is located on side of the cylinder block. (Scheme 71)- (Scheme 77). Manufacturer recommends removing knock sensor from cylinder block before testing. See appropriate N - REMOVE/INSTALL/OVERHAUL article.
2. 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 71

Scheme 72

Scheme 73

Scheme 74

Scheme 75

Scheme 76

Scheme 77

1. Ensure ignition is off. To test MAP sensor supply voltage, disconnect electrical connector from MAP sensor. See «MAP SENSOR LOCATION»(ref-95581-S19571715382001040200000) table. (Scheme 78)- (Scheme 82). MAP SENSOR LOCATION Application Location Camry In Engine Compartment, On Center Of Firewall Celica Passenger's Side Of Engine Compartment, On Firewall, Near Windshield Wiper Motor Corolla In Engine Compartment, On Top Of Throttle Body, Below Upper Radiator Hose RAV4 In Engine Compartment, On Firewall, Near Battery Tercel Passenger's Side Of Engine Compartment, On Firewall, Near Windshield Wiper Motor
2. Turn ignition on. Using voltmeter, check MAP sensor supply voltage between terminals E2 and VC on wiring harness side of electrical connector for MAP sensor. (Scheme 83) The E2 and VC terminals are the 2 outer terminals on all models. DO NOT use the center terminal.
3. The MAP sensor supply voltage should be 4.5-5.5 volts. If MAP sensor supply voltage is not within specification, check wiring circuit. See appropriate wiring diagram in L - WIRING DIAGRAMS article. If MAP sensor supply voltage is within specification, turn ignition off. Reinstall electrical connector on MAP sensor.
4. On Camry, Celica, RAV4 and Tercel, to test MAP sensor output voltage, turn ignition on. Disconnect vacuum hose from MAP sensor. Go to step 6.
5. On Corolla, to test MAP sensor output voltage, remove bolts and MAP sensor from throttle body. Turn ignition on. Go to next step.
6. On all models, connect voltmeter between the Engine Control Module (ECM) terminals E2 and PIM. (Scheme 84), (Scheme 85) or (Scheme 86). Refer to «ECM LOCATION (TABLE 2)»(ref-95581-S11079460402001040200000) table. Also, refer to «ECM TERMINAL APPLICATION (TABLE 1)»(ref-95581-S25152333762001040200000) table. ECM LOCATION (TABLE 2) Model Location Camry Behind Glove Box Celica Below Passenger's Side Of Instrument Panel, Underneath Carpet Near Center Console Corolla Behind Stereo On Instrument Panel, Just In Front Of Center Console RAV4 Behind Instrument Panel, Near Front Of Center Console Tercel Behind Glove Box ECM TERMINAL APPLICATION (TABLE 1) Application & Terminal Wire Color Camry E2 Brown PIM Black/Yellow Celica E2 Brown PIM Blue Corolla E2 Brown PIM Light Green/Red RAV4 E2 Brown PIM Light Green/Black Tercel E2 Brown PIM Pink
7. Measure and record output voltage under ambient atmospheric pressure. Attach vacuum pump to bottom of MAP sensor.
8. Apply vacuum in specified increments and measure MAP sensor output voltage drop at each increment. See «MAP SENSOR OUTPUT VOLTAGE DROP SPECIFICATIONS»(ref-95581-S27305559992001040200000) table. Replace MAP sensor if output voltage drop is not within specification.

MAP SENSOR OUTPUT VOLTAGE DROP SPECIFICATIONS

Scheme 78

Scheme 79

Scheme 80

Scheme 81

Scheme 82

Scheme 83

Scheme 84

Scheme 85

Scheme 86

Camry Calif. Emission Vehicles

1. A heated Air/Fuel (A/F) sensor is mounted on exhaust manifold. For testing of the A/F sensor, see «AIR/FUEL (A/F) SENSOR»(ref-95581-S10587455812001040200000). Another heated oxygen sensor is mounted on exhaust pipe behind catalytic converter. This oxygen sensor is referred to as bank No. 1 sensor No. 2, or rear oxygen sensor.
2. To test the heater resistance on bank No. 1 sensor No. 2, disconnect electrical connector for heated oxygen sensor. Electrical connector is a Dark Gray 4-pin electrical connector located below passenger's side front seat and carpet, near center console. (Scheme 87)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 87) 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 the Engine Control Module (ECM). For diagnosis of DTC, see appropriate G - TESTS W/CODES article.

Camry Except Calif. Emission Vehicles

1. A heated oxygen sensor is mounted near the exhaust manifold. This oxygen sensor is referred to as bank No. 1 sensor No. 1, or front oxygen sensor. Another heated oxygen sensor is mounted on exhaust pipe behind catalytic converter. This oxygen sensor is referred to as bank No. 1 sensor No. 2, or rear oxygen sensor.
2. To test the heater on any oxygen sensor, disconnect electrical connector for appropriate heated oxygen sensor. Electrical connector for bank No. 1 sensor No. 1 is located near the upper radiator hose. (Scheme 94) Electrical connector for bank No. 1 sensor No. 2 is a Dark Gray 4-pin electrical connector located below passenger's side front seat and carpet, near center console. (Scheme 87)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 87)and (Scheme 94). Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C).
4. If problem exists in either heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in the Engine Control Module (ECM). For diagnosis of DTC, see appropriate G - TESTS W/CODES article.

1. Two oxygen sensors are used. One oxygen sensor is mounted on exhaust manifold before front catalytic converter. This oxygen sensor is referred to as bank No. 1 sensor No. 1, or front oxygen sensor. Another oxygen sensor is mounted on bottom of front catalytic converter. This oxygen sensor is referred to as bank No. 1 sensor No. 2, or rear oxygen sensor.
2. If problem exists with either oxygen sensor or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in the Engine Control Module (ECM). For diagnosis of DTC, see appropriate G - TESTS W/CODES article.

Corolla

1. A heated oxygen sensor is mounted on exhaust pipe before catalytic converter. This oxygen sensor is referred to as bank No. 1 sensor No. 1, or front oxygen sensor. Another heated oxygen sensor is mounted on exhaust pipe behind catalytic converter. This oxygen sensor is referred to as bank No. 1 sensor No. 2, or rear oxygen sensor (Scheme 88)
2. To test the heater on any oxygen sensor, disconnect electrical connector for appropriate heated oxygen sensor. Electrical connector for bank No. 1 sensor No. 1 is located near exhaust manifold. (Scheme 95) Electrical connector for bank No. 1 sensor No. 2 is a Dark Gray 4-pin electrical connector located below passenger's side front seat and carpet, near center console. (Scheme 88)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 88)and (Scheme 95). Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C).
4. If problem exists in either heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in the Engine Control Module (ECM). For diagnosis of DTC, see appropriate G - TESTS W/CODES article.

RAV4 Calif. Emission Vehicles

1. A heated Air/Fuel (A/F) sensor is mounted on exhaust manifold. For testing of the A/F sensor, see «AIR/FUEL (A/F) SENSOR»(ref-95581-S10587455812001040200000). Another heated oxygen sensor is mounted on exhaust pipe behind catalytic converter. This oxygen sensor is referred to as bank No. 1 sensor No. 2, or rear oxygen sensor.
2. To test the heater resistance on bank No. 1 sensor No. 2, disconnect electrical connector for heated oxygen sensor. Electrical connector 5 is a Dark Gray 4-pin electrical connector located below passenger's side front seat and carpet, near center console. (Scheme 89)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 89) 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 the Engine Control Module (ECM). For diagnosis of DTC, see appropriate G - TESTS W/CODES article.

RAV4 Except Calif. Emission Vehicles

1. A heated oxygen sensor is mounted near the exhaust manifold. This oxygen sensor is referred to as bank No. 1 sensor No. 1, or front oxygen sensor. Another heated oxygen sensor is mounted on exhaust pipe behind catalytic converter. This oxygen sensor is referred to as bank No. 1 sensor No. 2, or rear oxygen sensor.
2. To test the heater on any oxygen sensor, disconnect electrical connector for appropriate heated oxygen sensor. Electrical connector for bank No. 1 sensor No. 1 is located near exhaust manifold. (Scheme 96) Electrical connector for bank No. 1 sensor No. 2 is a Dark Gray 4-pin electrical connector located below passenger's side front seat and carpet, near center console. (Scheme 89)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 89)- (Scheme 96). Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C).
4. If problem exists in either heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in the Engine Control Module (ECM). For diagnosis of DTC, see appropriate G - TESTS W/CODES article.

1. A heated oxygen sensor is mounted on exhaust pipe before catalytic converter. This oxygen sensor is referred to as bank No. 1 sensor No. 1, or front oxygen sensor. Another heated oxygen sensor is mounted on exhaust pipe behind catalytic converter. This oxygen sensor is referred to as bank No. 1 sensor No. 2, or rear oxygen sensor.
2. To test the heater on any oxygen sensor, disconnect electrical connector for appropriate heated oxygen sensor. (Scheme 90)- (Scheme 92) and (Scheme 97) - (Scheme 99). Using ohmmeter, check resistance between +B and HT terminals on electrical connector. Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C).
3. If problem exists in either heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in the Engine Control Module (ECM). For diagnosis of DTC, see appropriate G - TESTS W/CODES article.

1. Two oxygen sensors are used. A non-heated oxygen sensor is mounted on exhaust manifold. This oxygen sensor is referred to as bank No. 1 sensor No. 1, or front oxygen sensor. Another heated oxygen sensor is located on exhaust pipe behind catalytic converter. This oxygen sensor is referred to as bank No. 1 sensor No. 2, or rear oxygen sensor.
2. If problem exists with either oxygen sensor, heater (if equipped) or wiring circuit, a Diagnostic Trouble Code (DTC) will be stored in Engine Control Module (ECM). For diagnosis of DTC, see appropriate G - TESTS W/CODES article.
3. To test the heater on bank No. 1 sensor No. 2, disconnect electrical connector for heated oxygen sensor. Electrical connector for bank No. 1 sensor No. 2 is a Dark Gray 4-pin electrical connector located below passenger's side front seat and carpet, below center console. (Scheme 93)
4. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 93) Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C).

Scheme 87

Scheme 88

Scheme 89

Scheme 90

Scheme 91

Scheme 92

Scheme 93

Scheme 94

Scheme 95

Scheme 96

Scheme 97

Scheme 98

Scheme 99

A/T Models

1. Disconnect electrical connector from PNP switch. The PNP switch is mounted on side of transmission/transaxle. Note terminal identification. (Scheme 100)
2. Using ohmmeter, check for continuity between specified terminals with shift lever in proper positions. See «PARK/NEUTRAL POSITION SWITCH SPECIFICATIONS»(ref-95581-S01829942632001040200000) table. If proper continuity does not exist, adjust or replace switch as necessary.

PARK/NEUTRAL POSITION SWITCH SPECIFICATIONS

Scheme 100

Pick-up coil may also be referred to as a camshaft position sensor. For checking of pick-up coil, see PICK-UP COIL RESISTANCE and PICK-UP COIL AIR GAP under IGNITION CHECKS (DISTRIBUTOR TYPE IGNITION SYSTEM) in appropriate F - BASIC TESTING article.

Camry & Corolla

Power steering pressure switch is located on power steering pump, near the pressure hose. Testing information is not available at time of publication.

Camry & Celica

1. Ensure ignition is off. Disconnect electrical connector from Throttle Position (TP) sensor on throttle body. Note terminal identification on TP sensor. see scheme 39- see scheme 40. Disconnect vacuum nose and apply vacuum to throttle opener.
2. Using ohmmeter, check resistance between specified terminals in relation to throttle position. See «TP SENSOR RESISTANCE SPECIFICATIONS (CAMRY & CELICA 2.2L)»(ref-95581-S20990471932004022300000) table. Replace components as necessary if resistance is not within specification.

1. Ensure ignition is off. Disconnect electrical connector from Throttle Position (TP) sensor on throttle body. Note terminal identification on TP sensor. see scheme 41
2. Using ohmmeter, check resistance between specified terminals in relation to throttle position. See «TP SENSOR RESISTANCE SPECIFICATIONS (COROLLA - 1.8L)»(ref-95581-S10987909502004022300000) table. Replace components as necessary if resistance is not within specification.

RAV4

1. Note location of E2 terminal (Brown wire), VC terminal (Yellow wire) and VTA terminal (Blue/Red wire) on TP sensor. Ensure ignition is off. Disconnect electrical connector from Throttle Position (TP) sensor on throttle body. Apply vacuum to throttle opener.
2. Using ohmmeter, check resistance between specified terminals in relation to throttle position. See «TP SENSOR RESISTANCE SPECIFICATIONS (RAV4 - 2.0L)»(ref-95581-S17253528612004022300000) table. Replace components as necessary if resistance is not within specification.

1. Ensure ignition is off. Disconnect electrical connector from TP sensor on throttle body. Note terminal identification on TP sensor. see scheme 42 Apply vacuum to throttle opener.
2. Using ohmmeter, check resistance between specified terminals in relation to throttle position. See «TP SENSOR RESISTANCE SPECIFICATIONS (TACOMA - 2.4L & 2.7L)»(ref-95581-S21937061152004022300000) or «TP SENSOR RESISTANCE SPECIFICATIONS (T100 & 4RUNNER - 2.7L)»(ref-95581-S07704705032004022300000) table. Replace components as necessary if resistance is not within specification.

1. Ensure ignition is off. Disconnect electrical connector from TP sensor on throttle body. Note terminal identification. see scheme 43 On A/T models, disconnect throttle cable from linkage before checking TP sensor.
2. On all models, use ohmmeter to check resistance between specified terminals in relation to throttle position. See «TP SENSOR RESISTANCE SPECIFICATIONS (TERCEL - 1.5L)»(ref-95581-S42582787322004022300000) table. Replace components as necessary if resistance is not within specification.

Camry, Celica Calif. Emission Vehicles, Corolla, RAV4, Tacoma, Tercel, T100 & 4Runner

See FUEL EVAPORATIVE SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS.

Camry, Celica, Corolla & RAV4

1. Vehicle Speed Sensor (VSS) is mounted on transaxle and contains a 3-pin electrical connector. (Scheme 101) Connect voltmeter positive lead to terminal No. 3 (outer terminal) and negative lead to terminal No. 2 (center terminal) on VSS. (Scheme 102)and (Scheme 103).
2. Using jumper wires, connect positive battery terminal to terminal No. 1 (outer terminal) and negative battery terminal to terminal No. 2 (center terminal) on VSS. (Scheme 102)and (Scheme 103).
3. While rotating VSS shaft, ensure voltage changes from zero volts to at least 11 volts. Voltage should change 4 times per revolution of the shaft. Replace VSS if voltage does not change as specified. Remove test equipment.

Tacoma 2.4L 2RZ-FE

Vehicle Speed Sensor (VSS) is located on rear of combination meter in instrument cluster. Testing information is not available at time of publication.

Tacoma 2.7L 3RZ-FE & 4Runner

1. Vehicle Speed Sensor (VSS) is mounted on transmission and contains a 3-pin electrical connector. (Scheme 104) Connect voltmeter positive lead to terminal No. 3 (outer terminal) and negative lead to terminal No. 2 (center terminal) on VSS. (Scheme 105)or (Scheme 106).
2. Using jumper wires, connect positive battery terminal to terminal No. 1 (outer terminal) and negative battery terminal to terminal No. 2 (center terminal) on VSS. (Scheme 105)or (Scheme 106).
3. While rotating VSS shaft, ensure voltage changes from zero volts to at least 11 volts. Voltage should change 4 times per revolution of the shaft. Replace VSS if voltage does not change as specified. Remove test equipment.

Tercel & T100

1. Vehicle Speed Sensor (VSS) is located on rear of combination meter in instrument cluster. Connect ohmmeter between terminals "A" and "B" on rear of instrument cluster. (Scheme 107)- (Scheme 110).
2. Rotate speedometer cable shaft and note reading. Ohmmeter should deflect from continuity to no continuity 4 times per speedometer cable shaft revolution. Replace speedometer if reading does not deflect as specified.

Scheme 101

Scheme 102

Scheme 103

Scheme 104

Scheme 105

Scheme 106

Scheme 107

Scheme 108

Scheme 109

Scheme 110

1. The 4WD switch is located on side of transfer case and contains a Gray 2-pin electrical connector. Remove 4WD switch from transfer case. Connect ohmmeter between electrical terminals on 4WD switch.
2. Push pin on end of 4WD switch inward and ensure continuity exists. No continuity should exist when pin is released (outward) position. Replace 4WD switch if defective.

CIRCUIT OPENING RELAY

1. Ensure ignition is off. Remove circuit opening relay. See «CIRCUIT OPENING RELAY LOCATION»(ref-95581-S17675444622001040200000) table. (Scheme 111)- (Scheme 118). CIRCUIT OPENING RELAY LOCATION Application Location Camry (1) In Relay Box At Driver's Side Front Corner Of Engine Compartment, Near Battery & Air Cleaner Celica Below Passenger's Side Of Instrument Panel, Underneath Carpet, Near Center Console, Attached To Rear Of ECM Corolla Center Relay In Relay Box, Behind Driver's Side Kick Panel RAV4 Top Rear Relay In Relay Box Below Driver's Side Of Instrument Panel, Behind Kick Panel Tacoma Behind Lower Instrument Panel Cover, Next To Driver's Side Of Steering Column Tercel Near Top Right Corner Of Fuse/Relay Box Behind Driver's Side Lower Instrument Panel Cover, Near Steering Column T100 Behind Glove Box, Near Passenger's Side Kick Panel 4Runner Below Right Corner Of Fuse/Relay Box Behind Lower Instrument Panel Cover At Driver's Side Of Instrument Panel To Left Of Steering Column, Just Above Hood Release Lever (1) Circuit opening relay may be marked as CIR OPN relay in relay box.
2. To test circuit opening relay continuity, use ohmmeter to check for continuity and no continuity between specified terminals. (Scheme 119)- (Scheme 125).
3. To test circuit opening relay operation, apply battery voltage and ground to relay and use ohmmeter to check for continuity between specified terminals. (Scheme 119)- (Scheme 125). Replace circuit opening relay if defective.

Scheme 111

Scheme 112

Scheme 113

Scheme 114

Scheme 115

Scheme 116

Scheme 117

Scheme 118

Scheme 119

Scheme 120

Scheme 121

Scheme 122

Scheme 123

Scheme 124

Scheme 125

EFI MAIN RELAY

Note. EFI main relay may also be referred to as EFI relay.

1. Ensure ignition is off. Remove EFI main relay. See «EFI MAIN RELAY LOCATION»(ref-95581-S26269356282001040200000) table. EFI MAIN RELAY LOCATION Application Location Camry & Celica In Fuse/Relay Box At Driver's Side Front Corner Of Engine Compartment, Near Battery & Air Cleaner Corolla In Fuse/Relay Box At Driver's Side Front Corner Of Engine Compartment, Near Strut Tower RAV4 In Fuse/Relay Box Behind Driver's Side Of Instrument Panel, Next To Steering Column Tacoma, T100 & 4Runner In Fuse/Relay Box At Driver's Side Front Corner Of Engine Compartment, Near Battery Tercel In Fuse/Relay Box At Driver's Side Front Corner Of Engine Compartment, Near Strut Tower
2. To test EFI main relay continuity, use ohmmeter to check for continuity and no continuity between specified terminals.
3. To test EFI main relay operation, apply battery voltage and ground to relay and use ohmmeter to check for continuity between specified terminals. (Scheme 125)- (Scheme 127). Replace EFI main relay if defective.

Scheme 126

Scheme 127

See CIRCUIT OPENING RELAY under RELAYS.

See EFI MAIN RELAY under RELAYS.

Fuel Pump Pressure

For fuel pump pressure testing, see appropriate BASIC TESTING article.

Fuel Injectors (Camry, RAV4 & Tercel)

1. Ensure ignition is off. Disconnect electrical connector at fuel injector. Using ohmmeter, check resistance between electrical terminals on fuel injector. Replace fuel injector if resistance is not within specification. See «FUEL INJECTOR RESISTANCE»(ref-95581-S04762599792001040200000) table.
2. To check fuel injector volume, remove fuel injector. See appropriate N - REMOVE/INSTALL/OVERHAUL article. Ensure area around fuel hose on top of fuel filter is clean. Remove union bolts with gaskets, and disconnect fuel hose from top of fuel filter.
3. Install union, delivery hose, gaskets and union bolt on top of fuel filter. (Scheme 128) Tighten union bolt to 22 ft. lbs. (30 N.m).
4. Check that grommet and "O" ring are installed on top of fuel injector. Using clamp and union, connect fuel injector to the delivery hose.
5. 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 (DLC)-3. (Scheme 132)- (Scheme 134). 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-95581-S07732183862001040200000) under FUEL DELIVERY.
7. Connect Fuel Injector Tester (09842-30070) to fuel injector for 15 seconds. (Scheme 135) 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-95581-S20303129092001040200000) table. NOTE: Ensure difference between fuel injector volume on all fuel injectors is within specification. See «FUEL INJECTOR VOLUME SPECIFICATIONS»(ref-95581-S20303129092001040200000) table.
8. Disconnect fuel injector tester. Ensure fuel leakage from end of fuel injector does not exceed one drop in specified time. See «FUEL INJECTOR LEAKAGE SPECIFICATIONS»(ref-95581-S39841329552001040200000) table. Replace fuel injector if leakage exceeds specified amount. Disconnect negative battery cable. Remove test equipment.
9. Using NEW gaskets, install fuel hose on top of fuel filter. Tighten union bolt to 22 ft. lbs. (30 N.m). Install negative battery cable. Check for fuel leaks by using scan tool to energize fuel pump.

Fuel Injectors (Celica, Tacoma, T100 & 4Runner)

1. Ensure ignition is off. Disconnect electrical connector at fuel injector. Using ohmmeter, check resistance between electrical terminals on fuel injector. Replace fuel injector if resistance is not within specification. See «FUEL INJECTOR RESISTANCE»(ref-95581-S04762599792001040200000) table.
2. To check fuel injector volume, remove fuel injector. See appropriate N - REMOVE/INSTALL/OVERHAUL article. Ensure area around fuel hoses on fuel filter is clean. Remove union bolts with gaskets, and disconnect fuel hose from fuel filter. (Scheme 129)and (Scheme 131).
3. Install union, delivery hose, gaskets and union bolt on fuel filter. Tighten union bolt to 22 ft. lbs. (30 N.m).
4. Check that grommet (if equipped) and "O" ring are installed on top of fuel injector. Using clamp and union, connect fuel injector to the delivery hose.
5. Remove fuel pressure regulator from fuel rail. See appropriate REMOVE/INSTALL/OVERHAUL article. Using NEW "O" ring, install union on fuel pressure regulator. (Scheme 129)and (Scheme 131). Connect delivery hose to union and fuel return hose on fuel pressure regulator.
6. Place fuel injector into a clean graduated container. Place vinyl tube on end of fuel injector to prevent fuel spillage.
7. Connect scan tool to DLC-3. (Scheme 136)- (Scheme 139). 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-95581-S07732183862001040200000) under FUEL DELIVERY.
8. Connect Fuel Injector Tester (09842-30070) to fuel injector for 15 seconds. (Scheme 135) 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-95581-S20303129092001040200000) table. NOTE: Ensure difference between fuel injector volume on all fuel injectors is within specification. See «FUEL INJECTOR VOLUME SPECIFICATIONS»(ref-95581-S20303129092001040200000) table.
9. Disconnect fuel injector tester. Ensure fuel leakage from end of fuel injector does not exceed one drop in specified time. See «FUEL INJECTOR LEAKAGE SPECIFICATIONS»(ref-95581-S39841329552001040200000) table. Replace fuel injector if leakage exceeds specified amount. Disconnect negative battery cable. Remove test equipment.
10. Using NEW gaskets, install fuel hose on top of fuel filter. Tighten union bolt to 22 ft. lbs. (30 N.m). Reinstall fuel pressure regulator. Install negative battery cable. Check for fuel leaks by using scan tool to energize fuel pump.

Fuel Injectors (Corolla)

1. Ensure ignition is off. Disconnect electrical connector at fuel injector. Using ohmmeter, check resistance between electrical terminals on fuel injector. Replace fuel injector if resistance is not within specification. See «FUEL INJECTOR RESISTANCE»(ref-95581-S04762599792001040200000) table.
2. To check fuel injector volume, remove fuel injector. See appropriate N - REMOVE/INSTALL/OVERHAUL article. Remove fuel pipe clamp from end of fuel pipe at end of fuel rail if not previously done. Repeat step 1. (Scheme 141) Ensure area around fuel pipe and disconnect fitting is clean. CAUTION: Use care when disconnecting fuel pipe, as some residual fuel pressure may still exist in the fuel system.
3. Depress both sides of retainer and pull fuel pipe with disconnect fitting from fuel pipe fitting. Repeat step 2. (Scheme 141)
4. Purchase fuel pipe Part No. (23901-22010) from parts department. Remove fuel pipe connector from end of NEW fuel pipe and install on fuel pipe fitting and retainer. (Scheme 130) Ensure fuel pipe connector is securely attached on fuel pipe fitting and retainer is fully seated.
5. Connect delivery hose to fuel pipe connector. Check that grommet and "O" ring are installed on top of fuel injector. Using clamp and union, connect fuel injector to the delivery hose.
6. Place fuel injector into a clean graduated container. Place vinyl tube on end of fuel injector to prevent fuel spillage.
7. Connect scan tool to DLC-3. (Scheme 140) 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-95581-S07732183862001040200000) under FUEL DELIVERY.
8. Connect Fuel Injector Tester (09842-30080) to fuel injector for 15 seconds. (Scheme 135) 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-95581-S20303129092001040200000) table. NOTE: Ensure difference between fuel injector volume on all fuel injectors is within specification. See «FUEL INJECTOR VOLUME SPECIFICATIONS»(ref-95581-S20303129092001040200000) table.
9. Disconnect fuel injector tester. Ensure fuel leakage from end of fuel injector does not exceed one drop in specified time. See «FUEL INJECTOR LEAKAGE SPECIFICATIONS»(ref-95581-S39841329552001040200000) table. Replace fuel injector if leakage exceeds specified amount. Disconnect negative battery cable. Remove test equipment. CAUTION: DO NOT reuse old retainer when installing fuel pipe on fuel pipe fitting. Always use a NEW retainer.
10. Apply light coat of engine oil on tip of fuel pipe fitting to allow for ease of disconnect fitting and fuel pipe installation. Using NEW retainer, install fuel pipe on fuel pipe fitting until "click" sound is head. DO NOT reuse the old retainer. Pull on fuel pipe to ensure fuel pipe is properly locked on the fuel pipe fitting.
11. Reinstall fuel pipe clamp. Install negative battery cable. Check for fuel leaks by using scan tool to energize fuel pump.

FUEL INJECTOR RESISTANCE - Ohms @ 68°F (20°C)

FUEL INJECTOR VOLUME SPECIFICATIONS

FUEL INJECTOR LEAKAGE SPECIFICATIONS

Scheme 128

Scheme 129

Scheme 130

Scheme 131

Scheme 132

Scheme 133

Scheme 134

Scheme 135

Scheme 136

Scheme 137

Scheme 138

Scheme 139

Scheme 140

Scheme 141

Fuel Cut System

1. Connect scan tool to DLC-3. (Scheme 132)- (Scheme 134) or (Scheme 136) - (Scheme 140). Scan tool is used to read engine RPM. Start engine and warm engine to normal operating temperature.
2. Ensure A/C and all accessories are off. Gradually increase engine speed to specified RPM. See «FUEL CUT SYSTEM TESTING SPEED»(ref-95581-S36133643662001040200000) table. FUEL CUT SYSTEM TESTING SPEED Application Engine RPM Camry & Celica 2500 Corolla 3500 RAV4 2500 Tacoma 3500 Tercel 2500 T100 3000 4Runner 3500
3. 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).
4. Ensure fuel return RPM is within specification. See «FUEL CUT SPECIFICATIONS SYSTEM»(ref-95581-S27968964092001040200000) table. Shut engine off. Remove test equipment.

FUEL CUT SPECIFICATIONS (1)

Camry, Celica, RAV4, Tacoma, T100 & 4Runner

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in appropriate D - ADJUSTMENTS article.
2. Turn ignition off. Apply parking brake and place transmission/transaxle in Neutral. Install Jumper Wire (SST 09843-18020) between terminals TE1 and E1 on Data Link Connector (DLC)-1. (Scheme 142)- (Scheme 146). See «DLC-1 LOCATIONS»(ref-95581-S29373473562001040200000) table.
3. Start engine and note engine RPM. After engine RPM is kept at specified RPM for 5 seconds, ensure engine returns to idle speed. See «IAC VALVE ENGINE SPEED TESTING SPECIFICATIONS»(ref-95581-S32853513912001040200000) table. DLC-1 LOCATIONS Application Location Camry Passenger's Side Of Engine Bay, Near Strut Tower Celica Driver's Side Rear Corner Of Engine Bay, Near Brake Booster RAV4 On Timing Belt End Of Engine, Above Generator Tacoma, T100 & 4Runner On End Of Air Intake Chamber At Front Of Engine IAC VALVE ENGINE SPEED TESTING SPECIFICATIONS Application Engine RPM Camry, Celica & RAV4 900-1300 Tacoma, T100 & 4Runner 1000-1500
4. If engine speed is not as specified, test IAC valve resistance and IAC valve operation. If engine speed is as specified, remove jumper wire. Turn ignition off.
5. To test IAC valve resistance, ensure ignition is off. Disconnect electrical connector from IAC valve. IAC valve is located on lower area of throttle body. Using ohmmeter, checking resistance between +B terminal and each remaining terminal on IAC valve. (Scheme 147)- (Scheme 150).
6. Replace IAC valve if resistance is not within specification. See «IAC VALVE RESISTANCE SPECIFICATIONS»(ref-95581-S15780046842001040200000) table. IAC VALVE RESISTANCE SPECIFICATIONS Application Ohms All Models Cold (1) 17.0-24.5 Hot (2) 21.5-28.5 (1) Cold is with temperature of 14-122°F (-10-50°C). (2) Hot is with temperature of 122-212°F (50-100°C).
7. To test IAC valve operation, remove IAC valve from throttle body. See appropriate N - REMOVE/INSTALL/OVERHAUL article. Apply battery voltage to +B terminal on IAC valve. (Scheme 151)- (Scheme 153). Apply battery ground terminal to proper terminal and ensure valve opens and closes. Replace IAC valve if defective.
8. If IAC valve resistance is within specification and operates correctly, check wiring circuit between Engine Control Module (ECM) and IAC valve. See «ECM LOCATION (TABLE 3)»(ref-95581-S14451250532001040200000) table. See appropriate wiring diagram in L - WIRING DIAGRAMS article.

Corolla & Tercel

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in appropriate D - ADJUSTMENTS article.
2. Turn ignition off. Apply parking brake and place transaxle in Neutral. Install Jumper Wire (SST 09843-18020) between terminals TE1 and E1 on DLC-1. (Scheme 154)and (Scheme 155). DLC-1 is located at driver's side of engine compartment, near strut tower.
3. Start engine and note engine RPM. After engine RPM is kept at 900-1300 RPM for 5 seconds, ensure engine returns to idle speed. If engine speed is not as specified, test IAC valve operation. If engine speed is as specified, remove jumper wire. Turn ignition off.
4. To test IAC valve operation, remove IAC valve from throttle body. See appropriate N - REMOVE/INSTALL/OVERHAUL article. Check that valve on inside of IAC valve is half open. (Scheme 156) Reinstall electrical connector on IAC valve.
5. Disconnect electrical connector from Engine Coolant Temperature (ECT) sensor. See «ENGINE COOLANT TEMPERATURE (ECT) SENSOR LOCATION»(ref-95581-S24171904822001040200000) table. ENGINE COOLANT TEMPERATURE (ECT) SENSOR LOCATION Model Location Corolla On Flywheel End Of Cylinder Head Below Ignition Coil & Contains Dark Gray 2-Pin Electrical Connector With White & Brown Wires Tercel On Coolant Housing At Flywheel End Of Cylinder Head & Contains Dark Gray 2-Pin Electrical Connector With Black/Red & Brown Wires
6. Turn ignition on. Check that valve on inside of IAC valve moves. Repeatedly disconnect and reconnect electrical connector for IAC valve several times while checking that valve on inside of IAC valve opens and closes. (Scheme 156)
7. Turn ignition off. Reinstall electrical connector on ECT sensor. Remove jumper wire.
8. If IAC valve operates, wiring circuit, Engine Control Module (ECM) and IAC valve are okay. If IAC valve does not operate, check wiring circuit between the ECM and the IAC valve. Refer to the «ECM LOCATION (TABLE 3)»(ref-95581-S14451250532001040200000) table. See appropriate wiring diagram in L - WIRING DIAGRAMS article. If wiring circuit and ECM are okay, replace IAC valve.

ECM LOCATION (TABLE 3)

Scheme 142

Scheme 143

Scheme 144

Scheme 145

Scheme 146

Scheme 147

Scheme 148

Scheme 149

Scheme 150

Scheme 151

Scheme 152

Scheme 153

Scheme 154

Scheme 155

Scheme 156

* PLEASE READ FIRST *

Note. For basic ignition checks, see appropriate F - BASIC TESTING article.

See KNOCK SENSOR under ENGINE SENSORS & SWITCHES.

Camry, Celica & RAV4

1. Remove cap and filter from top of EGR vacuum modulator. Ensure filter is clean and in good condition. Clean filter with compressed air (if necessary). NOTE: Filter must be installed in EGR vacuum modulator with coarse side facing upward, away from EGR vacuum modulator.
2. Reinstall filter and cap. Using 3-way connector, install vacuum gauge in vacuum hose on top of EGR valve. This is the vacuum hose that goes from top of EGR valve to EGR Vacuum Switching Valve (VSV). Start engine. Ensure engine idles smoothly to ensure proper seating of EGR valve.
3. Install Jumper Wire (SST 09843-18020) between terminals TE1 and E1 on DLC-1. (Scheme 142)- (Scheme 144). See «DLC-1 LOCATIONS»(ref-95581-S29373473562001040200000) table. DLC-1 LOCATIONS Application Location Camry Passenger's Side Of Engine Bay, Near Strut Tower Celica Driver's Side Rear Corner Of Engine Bay, Near Brake Booster RAV4 On Timing Belt End Of Engine, Above Generator
4. To test operation of EGR VSV with engine cold, ensure engine coolant temperature is less than 131°F (55°C). Increase and maintain engine speed at 2500 RPM. Ensure no vacuum reading is obtained on vacuum gauge with engine speed at 2500 RPM.
5. To test operation of EGR VSV with engine warm, operate engine until engine coolant temperature is greater than 140°F (60°C). Operate engine at 2500 RPM again. Ensure a low vacuum reading is obtained on vacuum gauge with engine speed at 2500 RPM.
6. Disconnect vacuum hose from port "R" on EGR vacuum modulator. (Scheme 157) Using additional hose, connect port "R" on EGR vacuum modulator directly to intake manifold. Operate engine at 2500 RPM again. High vacuum reading should be obtained at 2500 RPM. NOTE: Engine should misfire due to large amounts of exhaust gas being injected into intake manifold.
7. Shut engine off. Remove vacuum hose, vacuum gauge and reconnect original vacuum hoses. Remove jumper wire from DLC-1.
8. To test EGR valve operation, remove and plug vacuum hose located on top of EGR valve. Start engine. Using vacuum pump, apply vacuum directly to EGR valve with engine idling. Engine should run rough or stall if EGR valve is operating properly. If EGR system does not operate as described, each individual component should be tested. Shut engine off.

1. Remove cap and filter from top of EGR vacuum modulator. Ensure filter is clean and in good condition. Clean filter with compressed air (if necessary). NOTE: Filter must be installed in EGR vacuum modulator with coarse side facing upward, away from EGR vacuum modulator.
2. Reinstall filter and cap. Using 3-way connector, install vacuum gauge in vacuum hose between top of EGR valve and EGR vacuum modulator. Repeat step 1. (Scheme 158) Start engine. Ensure engine idles smoothly to ensure proper seating of EGR valve.
3. To test operation of EGR VSV with engine cold, ensure engine coolant temperature is less than 122°F (50°C). Increase and maintain engine speed at 3500 RPM. Ensure no vacuum reading is obtained on vacuum gauge with engine speed at 3500 RPM and EGR pipe is not hot.
4. To test operation of EGR VSV and EGR vacuum modulator. Shut engine off. This test procedure may be performed by using scan tool to operate EGR VSV, or by connecting vacuum hose from port "Q" on EGR vacuum modulator to EGR valve. If using scan tool, go to next step. If scan tool is not available, go to step 6.
5. Connect scan tool to DLC-3. (Scheme 137)- (Scheme 139). Select ACTIVE TEST MODE on scan tool so EGR VSV is closed. Start engine. Operate engine at 3500 RPM again. Ensure a low vacuum reading is obtained on vacuum gauge with engine speed at 3500 RPM. Shut engine off. Remove scan tool. Go to step 8.
6. Remove 3-way connector and small vacuum hose between port "Q" (single port) on EGR vacuum modulator and the EGR valve. Repeat step 2. (Scheme 157) This 3-way connector and small vacuum hose goes from EGR valve and EGR vacuum modulator to the EGR VSV. Install plug in vacuum hose to EGR VSV.
7. Connect vacuum hose from port "Q" on EGR vacuum modulator to directly to the EGR valve. (Scheme 157) This will by-pass the EGR VSV. Start engine. Operate engine at 3500 RPM again. Ensure a low vacuum reading is obtained on vacuum gauge with engine speed at 3500 RPM. Shut engine off. Reconnect vacuum hoses. Go to next step.
8. To check EGR valve operation, remove and plug hose at EGR valve. Using vacuum pump, apply vacuum directly to EGR valve with engine idling. Engine should run rough or stall. If EGR system does not operate as described, each individual component should be tested.

Scheme 157

Scheme 158

Scheme 159

Scheme 160

Scheme 161

Scheme 162

Scheme 163

Scheme 164

Scheme 165

Tacoma With A/T, T100 With A/T & 4Runner With A/T

1. Remove EGR check valve. (Scheme 163)and (Scheme 164). Apply air pressure on Orange-colored side of EGR check valve. Air should flow through EGR check valve.
2. Apply air pressure on Black-colored side of EGR check valve. Air should not flow through EGR check valve. Replace EGR check valve if defective. Reinstall EGR check valve with Orange-colored side of EGR check valve toward EGR vacuum modulator.

See EGR GAS TEMPERATURE SENSOR under ENGINE SENSORS & SWITCHES.

EGR VACUUM MODULATOR

Note. When testing EGR vacuum modulator, it may be necessary to 55 monitor engine RPM by using scan tool. Scan tool may be connected to DLC-3 for monitoring engine RPM. (Scheme 132)- (Scheme 134) or (Scheme 136) - (Scheme 140).

1. Mark vacuum hose locations and disconnect vacuum hoses from EGR vacuum modulator. (Scheme 159), (Scheme 160), (Scheme 162), (Scheme 163) and (Scheme 164). Block ports "P" and "R" on EGR vacuum modulator. (Scheme 157) NOTE: Ports "P" and "R" are the double ports on side of EGR vacuum modulator. Port "Q" is single port on side of EGR vacuum modulator.
2. Apply air pressure to port "Q". (Scheme 157) Air should flow freely through air filter side of EGR vacuum modulator.
3. Start engine and operate engine at specified RPM. See «EGR VACUUM MODULATOR TESTING SPECIFICATIONS»(ref-95581-S41943470222001040200000) table. Repeat test procedures in steps 1 and 2. Strong resistance of airflow should be felt with engine at specified RPM. Replace EGR vacuum modulator if strong resistance is not felt. Reconnect vacuum hoses to proper locations.

EGR VACUUM MODULATOR TESTING SPECIFICATIONS

1. Disconnect electrical connector from EGR VSV. See «EGR VSV LOCATIONS»(ref-95581-S26743652562001040200000) table. (Scheme 159), (Scheme 160) and (Scheme 162). Using ohmmeter, check that continuity exists between electrical terminals on EGR VSV and resistance is 33-39 ohms at 68°F (20°C). Replace EGR VSV if no continuity exists or resistance is not within specification.
2. Ensure no continuity exists between each electrical terminal and body of EGR VSV. Replace EGR VSV if continuity exists between electrical terminal and the body of EGR VSV.
3. To test EGR VSV operation, apply air pressure to port "E". Ensure air flows from port "G". Repeat step 1. (Scheme 166) Apply battery voltage and ground to electrical terminals on EGR VSV.
4. Apply air pressure to port "E". Ensure air flows from filter and not from port "G". Repeat step 2. (Scheme 166) Replace EGR VSV if defective.

1. Disconnect electrical connector from EGR VSV. See «EGR VSV LOCATIONS»(ref-95581-S26743652562001040200000) table. (Scheme 163)and (Scheme 164). Using ohmmeter, check that continuity exists between electrical terminals on EGR VSV and resistance is 33-39 ohms at 68°F (20°C). Replace EGR VSV if no continuity exists or resistance is not within specification.
2. Ensure no continuity exists between each electrical terminal and the body of EGR VSV body. Replace EGR VSV if continuity exists between electrical terminal and the body of EGR VSV.
3. To test EGR VSV operation, apply air pressure to port "E". Ensure no air flows from port "F". Repeat step 1. (Scheme 167) Apply battery voltage and ground to electrical terminals on EGR VSV.
4. Apply air pressure to port "E". Ensure air flows from port "F". Repeat step 2. (Scheme 167) Replace EGR VSV if defective.

EGR VSV LOCATIONS

Scheme 166

Scheme 167

1. Remove EGR valve. See appropriate N - REMOVE/INSTALL/OVERHAUL article.
2. Inspect EGR valve for restricted passages caused by carbon deposits. Using vacuum pump, apply vacuum directly to EGR valve and ensure valve opens. Release vacuum and ensure valve closes. Replace EGR valve if defective.

FUEL EVAPORATION SYSTEM

Note. Fuel evaporation systems contain different components depending on application. (Scheme 159)- (Scheme 165). When testing fuel evaporation system components, it may be necessary to use proper illustration to determine component location.

Note. On Camry and Corolla, an On-Board Refilling Vapor Recovery (ORVR) system is used to recover fuel vapors into the charcoal canister that are generated during refueling. ORVR system consists of fuel inlet pipe, overfill check valve, cut-off valve and charcoal canister. (Scheme 159)- (Scheme 165). Overfill check valve may also be referred to as On-Board Refueling Vapor Recovery Overfill Check Valve (ORVR-OCKV) or fill check valve. Cut-off valve may also be referred to On-Board Refueling Vapor Recovery Cut-Off Valve (ORVR-COV). For testing of ORVR system components, see ON-BOARD REFILLING VAPOR RECOVERY (ORVR) SYSTEM.

Note. Charcoal canister may also be referred to as EVAP canister.

Charcoal Canister (Camry)

For testing of charcoal canister, see CHARCOAL CANISTER (CAMRY) under ON-BOARD REFILLING VAPOR RECOVERY (ORVR) SYSTEM.

Charcoal Canister (Celica Except Calif. Emission Vehicles)

1. Remove charcoal canister. (Scheme 160) Inspect charcoal canister for cracks or damage. Check for clogged filter and/or stuck check valve by applying.68 psi (.048 kg/cm 2 ) air pressure to port "A". (Scheme 170) Ensure air flows freely from other ports on charcoal canister.
2. Apply.68 psi (.048 kg/cm 2 ) air pressure to port "B". (Scheme 170) Ensure air does not flow 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. (Scheme 170) Air should flow from remaining port on charcoal canister. Ensure no activated carbon comes out of charcoal canister. DO NOT attempt to wash out charcoal canister.

Charcoal Canister (Celica Calif. Emission Vehicles)

1. Manufacturer provides testing information for checking airtightness of fuel tank and components along with testing of EVAP canister. Inspect all lines and connections for sharp bends or damage. 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. To check airtightness of fuel tank and fuel inlet pipe, disconnect EVAP line hose from charcoal canister. Repeat step 1. (Scheme 168) EVAP canister is located near fuel tank. (Scheme 160) Apply.58 psi (.040 kg/cm 2 ) air pressure to EVAP line hose so that the pressure inside the fuel tank is.58 psi (.040 kg/cm 2 ). Check that pressure inside the fuel tank will hold steady for one minute.
3. If pressure inside the fuel tank will hold steady for one minute, reinstall EVAP line hose on charcoal canister. Go to next step. If pressure inside the fuel will not hold steady for one minute, check for leaking hoses or pipes at fuel tank and fuel inlet pipe, or for leaks at the fuel tank. If no leaks exist, replace fuel tank and fuel inlet pipe. Reinstall EVAP line hose on charcoal canister. Go to next step.
4. To check overfill check valve, disconnect purge line hose and EVAP line hose from charcoal canister, and install cap on air drain hose. Repeat step 2. (Scheme 168)
5. Apply.58 psi (.040 kg/cm 2 ) air pressure to purge line hose fitting on charcoal canister. Repeat step 2. (Scheme 168) 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 the overfill check valve is may be closed. Ensure fuel tank is not full of fuel when checking for airflow at EVAP line hose.
6. 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 purge line hose. If any hose is restricted, replace hose and recheck operation. If hoses are not restricted, replace overfill check valve located on top of fuel tank. (Scheme 160)
7. To check air inlet line, disconnect air inlet line hose from charcoal canister. Repeat step 3. (Scheme 168) 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.
8. Remove charcoal canister. (Scheme 160) Inspect charcoal canister for cracks or damage.
9. Install cap on vent port on charcoal canister. (Scheme 170) Apply.26 psi (.018 kg/cm 2 ) air pressure to EVAP port while holding purge port closed. (Scheme 170) Ensure air flows freely from air drain port.
10. Apply.26 psi (.018 kg/cm 2 ) air pressure to EVAP port while holding air drain port and purge port closed. (Scheme 168) Ensure no air flows from air inlet port.
11. Using vacuum pump, apply 1.01 in. Hg of vacuum to purge port. Ensure vacuum does not decrease when air inlet port is closed, and that vacuum decreases when air inlet port is opened.
12. While holding air inlet port closed, use vacuum pump to apply 1.01 in. Hg of vacuum to EVAP port. Ensure air flows into purge port. Replace charcoal canister if defective.

Scheme 168

Charcoal Canister (Corolla)

For testing of charcoal canister, see CHARCOAL CANISTER (COROLLA) under ON-BOARD REFILLING VAPOR RECOVERY (ORVR) SYSTEM.

Charcoal Canister (RAV4)

1. Remove charcoal canister. (Scheme 162) Inspect charcoal canister for cracks or damage. Install plug on port "E" on charcoal canister. (Scheme 171)
2. Check for clogged filter and/or stuck check valve and diaphragm by applying.26 psi (.018 kg/cm 2 ) air pressure to port "A" while holding port "B" closed. (Scheme 171) Ensure air flows freely from port "D".
3. Apply.26 psi (.018 kg/cm 2 ) air pressure to port "A" while holding ports "B" and "D" closed. (Scheme 171) Ensure no air flows from port "C".
4. Using vacuum pump, apply one 1.01 in. Hg of vacuum to port "B". Ensure vacuum does not decrease when port "C" is closed, and that vacuum decreases when port "C" is opened.
5. While holding port "C" closed, use vacuum pump to apply.36 in. Hg of vacuum to port "A". Ensure air flows into port "B". Replace charcoal canister if defective.

Charcoal Canister (Tacoma & 4Runner)

1. Remove charcoal canister. (Scheme 163) Inspect charcoal canister for cracks or damage. Install plugs on ports "A" and "B" on charcoal canister. (Scheme 172)
2. Check for clogged filter and/or stuck check valve and diaphragm by applying.21 psi (.015 kg/cm 2 ) air pressure to port "D" while holding port "C" closed. (Scheme 172) Ensure air flows freely from port "E".
3. Apply.21 psi (.015 kg/cm 2 ) air pressure to port "D" while holding ports "C" and "E" closed. (Scheme 172) Ensure no air flows from port "F".
4. Using vacuum pump, apply.87 in. Hg of vacuum to port "C". Ensure vacuum does not decrease when port "F" is closed, and that vacuum decreases when port "F" is opened.
5. While holding port "F" closed, use vacuum pump to apply.87 in. Hg of vacuum to port "D". Ensure vacuum does not decrease when port "C" is closed, and that vacuum decreases with port "C" is opened. Replace charcoal canister if defective.

Charcoal Canister (Tercel)

1. Remove charcoal canister. (Scheme 165) Inspect charcoal canister for cracks or damage. Install plug on port "E" on charcoal canister. (Scheme 173)
2. Check for clogged filter and/or stuck check valve and diaphragm by applying.26 psi (.018 kg/cm 2 ) air pressure to port "A" while holding port "B" closed. (Scheme 173) Ensure air flows freely from port "D".
3. Apply.26 psi (.018 kg/cm 2 ) air pressure to port "A" while holding ports "B" and "D" closed. (Scheme 173) Ensure no air flows from port "C".
4. Using vacuum pump, apply.87 in. Hg of vacuum to port "B". Ensure vacuum does not decrease when port "C" is closed, and that vacuum decreases when port "C" is opened.
5. While holding port "C" closed, use vacuum pump to apply.43 in. Hg of vacuum to port "A". Ensure air flows into port "B". Replace charcoal canister if defective.

Charcoal Canister (T100)

1. Remove charcoal canister. (Scheme 164) Inspect charcoal canister for cracks or damage. Install plug on port "E" on charcoal canister. (Scheme 174)
2. Check for clogged filter and/or stuck check valve and diaphragm by applying.21 psi (.015 kg/cm 2 ) air pressure to port "A" while holding port "B" closed. (Scheme 174) Ensure air flows freely from port "D".
3. Apply.26 psi (.018 kg/cm 2 ) air pressure to port "A" while holding ports "B" and "D" closed. (Scheme 174) Ensure no air flows from port "C".
4. Using vacuum pump, apply 1.01 in. Hg of vacuum to port "B". Ensure vacuum does not decrease when port "C" is closed, and that vacuum decreases when port "C" is opened.
5. While holding port "C" closed, use vacuum pump to apply.36 in. Hg of vacuum to port "A". Ensure air flows into port "B". Replace charcoal canister if defective.

Scheme 169

Scheme 170

Scheme 171

Scheme 172

Scheme 173

Scheme 174

Cut-Off Valve (Camry & Corolla)

For testing of cut-off valve, see CHARCOAL CANISTER (CAMRY) or CHARCOAL CANISTER (COROLLA) under ON-BOARD REFILLING VAPOR RECOVERY (ORVR) SYSTEM.

EVAP Check Valve (Celica Except Calif. Emission Vehicles)

1. Remove EVAP check valve from lower hoses on charcoal canister. (Scheme 160) Apply air pressure to Yellow-colored port at end of EVAP check valve. Air should pass through both White-colored ports on side of EVAP check valve.
2. Place finger over end of one White-colored port on side on EVAP check valve. Apply air pressure to remaining White-colored port on side on EVAP check valve. Air should not flow out the Yellow-colored port at end of EVAP check valve. Replace EVAP check valve if defective.

EVAP Thermal Vacuum Valve (Celica Except Calif. Emission Vehicles)

Testing information is not available at time of publication.

EVAP Vacuum Switching Valve (Camry, Celica Calif. Emission Vehicles, Corolla, RAV4, Tacoma, Tercel, T100 & 4Runner)

1. Remove EVAP Vacuum Switching Valve (VSV). See «EVAP VSV LOCATION»(ref-95581-S40877691302001040200000) table. (Scheme 159)- (Scheme 165). EVAP VSV LOCATION Application Location Camry On Bracket Near Air Filter Housing & Driver's Side Strut Tower, & Contains 2-Pin Electrical Connector With Violet/White & Black/Yellow Wires Celica On Bracket Near Air Filter Housing & Driver's Side Strut Tower, & Contains 2-Pin Electrical Connector With Light Green/Black & Black/Red Wires Corolla On Bracket At Rear Of Air Filter Housing & Contains 2-Pin Electrical Connector With Blue/Black & Black Wires RAV4 On Bracket At Rear Of Air Filter Housing & Contains 2-Pin Electrical Connector With Black/Red & Pink Wires Tacoma Bolted To End Of Charcoal Canister & Contains 2-Pin Electrical Connector With White/Red & White/Green Wires Tercel Bolted To Side Of Air Intake, Near Air Filter & Contains 2-Pin Electrical Connector With Black/Red & Blue/White Wires T100 Mounted On Top Of Charcoal Canister & Contains 2-Pin Electrical Connector With White/Red & White/Green Wires 4Runner Bolted To End Of Charcoal Canister & Contains 2-Pin Electrical Connector With White/Blue & Black/White Wires
2. Using ohmmeter, ensure continuity exists between electrical terminals on EVAP VSV and resistance is within specification. See «EVAP VSV RESISTANCE»(ref-95581-S17424380762001040200000) table. Replace EVAP VSV if no continuity exists or resistance is not within specification. EVAP VSV RESISTANCE Application Ohms @ 68°F (20°C) Camry & Celica 30-34 Corolla & Tercel 27-33 RAV4, Tacoma, T100 & 4Runner 30-34
3. Ensure no continuity exists between each electrical terminal and the body of the EVAP VSV. Replace EVAP VSV if continuity exists between electrical terminal and body of EVAP VSV.
4. To test EVAP VSV operation, apply air pressure to port "E". Ensure air does not flow from port "F". Repeat step 1. (Scheme 175)
5. Apply battery voltage and ground to electrical terminals on EVAP VSV. Apply air pressure to port "E". Ensure air flows from port "F". Repeat step 2. (Scheme 175) Replace EVAP VSV if defective.

Scheme 175

Overfill Check Valve (Camry & Corolla)

For testing of overfill check valve, see CHARCOAL CANISTER (CAMRY) or CHARCOAL CANISTER (COROLLA) under ON-BOARD REFILLING VAPOR RECOVERY (ORVR) SYSTEM.

Overfill Check Valve (Celica Calif. Emission Vehicles)

For testing of overfill check valve, see CHARCOAL CANISTER (CELICA CALIF. EMISSION VEHICLES) under FUEL EVAPORATION SYSTEM.

Scheme 176

Scheme 177

Scheme 178

Scheme 179

Scheme 180

1. Ensure ignition is off. To test vapor pressure sensor supply voltage, disconnect electrical connector from vapor pressure sensor. (Scheme 159)- (Scheme 165). See «VAPOR PRESSURE SENSOR LOCATION»(ref-95581-S35797579862001040200000) table. VAPOR PRESSURE SENSOR LOCATION Application Location Camry On Charcoal Canister, Near Fuel Tank & Contains Black 3-Pin Electrical Connector With Brown, Pink & Yellow Wires Celica At Charcoal Canister, Near Fuel Tank & Contains Black 3-Pin Electrical Connector With Brown, Red & Red/White Wires Corolla At Charcoal Canister, Near Fuel Tank & Contains Black 3-Pin Electrical Connector With Brown, Blue & Yellow Wires RAV4 On Firewall, Above Brake Booster & Contains Black 3-Pin Electrical Connector With Brown, Blue & Blue/Yellow Wires Tacoma On Firewall, Above Brake Booster & Contains Black 3-Pin Electrical Connector With Brown/Black, Green/Yellow & Red/Yellow Wires Tercel On Bracket, Just In Front Of Windshield Wiper Motor Near Passenger's Side Strut Tower & Contains Black 3-Pin Electrical Connector With Brown, Light Green/Red & Yellow/Black Wires T100 On Firewall, Above Brake Booster & Contains Black 3-Pin Electrical Connector With Brown/Black, Green/Yellow & Red/Blue Wires 4Runner On Firewall, Above Brake Booster & Contains Black 3-Pin Electrical Connector With Brown/Black, Green/Yellow & Light Green/Black Wires
2. Turn ignition on. Using voltmeter, measure voltage between terminals VC and E2 on wiring harness side of electrical connector for vapor pressure sensor. The VC and E2 terminals are the 2 outer terminals. DO NOT use the center terminal. 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 L - 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 proper vacuum hose from vapor pressure sensor. (Scheme 176)- (Scheme 180). Obtain access to Engine Control Module (ECM). See «ECM LOCATION (TABLE 4)»(ref-95581-S42285920252001040200000) table. ECM LOCATION (TABLE 4) Model Location Camry Behind Glove Box Celica Below Passenger's Side Of Instrument Panel, Underneath Carpet Near Center Console Corolla Behind Stereo On Instrument Panel, Just In Front Of Center Console RAV4 Behind Instrument Panel, Near Front Of Center Console Tacoma & Tercel Behind Glove Box T100 Behind Passenger's Side Kick Panel 4Runner Behind Glove Box
5. Connect voltmeter between specified ECM terminals. (Scheme 181)- (Scheme 184). See «ECM TERMINAL APPLICATION (TABLE 2)»(ref-95581-S39903590862001040200000) table. ECM TERMINAL APPLICATION (TABLE 2) Application & Terminal Wire Color Camry E2 Brown PTNK Pink Celica E2 Brown PTNK Red/White Corolla E2 Brown PTNK Blue RAV4 E2 Brown PTNK Blue/Yellow Tacoma E2 Brown/Black PTNK Red/Yellow Tercel E2 Brown/Black PTNK Yellow/Black T100 E2 Brown/Black PTNK Red/Blue 4Runner E2 Brown/Black PTNK Light Green/Black
6. Using vacuum pump, apply.59 in. Hg of vacuum to vapor pressure sensor. Ensure output voltage is within specification. See «VAPOR SENSOR OUTPUT VOLTAGE»(ref-95581-S25739947192001040200000) table.
7. Release vacuum from vapor pressure sensor. Ensure output voltage is within specification. See «VAPOR SENSOR OUTPUT VOLTAGE»(ref-95581-S25739947192001040200000) table.
8. Apply.22 psi (.015 kg/cm 2 ) of pressure to vapor pressure sensor. Ensure output voltage is within specification. See «VAPOR SENSOR OUTPUT VOLTAGE»(ref-95581-S25739947192001040200000) table. Replace vapor sensor if output voltage is not within specification. Reconnect vacuum hose.

VAPOR SENSOR OUTPUT VOLTAGE

Scheme 181

Scheme 182

Scheme 183

Scheme 184

Vapor Pressure Sensor Vacuum Switching Valve (Camry, Celica Calif. Emission Vehicles, Corolla, RAV4, Tacoma, Tercel, T100 & 4Runner)

1. Remove vapor pressure sensor Vacuum Switching Valve (VSV). (Scheme 159)- (Scheme 165). See «VAPOR PRESSURE SENSOR VSV LOCATION»(ref-95581-S25094885722001040200000) table. VAPOR PRESSURE SENSOR VSV LOCATION Application Location Camry, Celica & Corolla On Charcoal Canister, Near Fuel Tank RAV4 & Tacoma On Top Of Charcoal Canister Tercel On Bracket, Just In Front Of Windshield Wiper Motor Near Vapor Pressure Sensor T100 On Top Rear Corner Of Charcoal Canister 4Runner On Top Of Charcoal Canister
2. Using ohmmeter, ensure continuity exists between electrical terminals on vapor pressure sensor VSV and resistance is within specification. See «VAPOR PRESSURE SENSOR VSV RESISTANCE»(ref-95581-S37774805252001040200000) table. Replace vapor pressure sensor VSV if no continuity exists or resistance is not within specification. VAPOR PRESSURE SENSOR VSV RESISTANCE Application Ohms @ 68°F (20°C) Camry & Celica 33-39 Corolla 37-44 RAV4 33-39 Tacoma, Tercel, T100 & 4Runner 37-44
3. Ensure no continuity exists between each electrical terminal and the body of vapor pressure sensor VSV. Replace vapor pressure sensor VSV if continuity exists between electrical terminal and body of vapor pressure sensor VSV.
4. To test vapor pressure sensor VSV operation, apply air pressure to port "E". Ensure air flows from port "G" and not from port "F". Repeat step 1. (Scheme 185)
5. 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". Repeat step 2. (Scheme 185) Replace vapor pressure sensor VSV if defective.

Scheme 185

1. Manufacturer provides testing information for checking airtightness of fuel tank and components along with testing of charcoal canister. Inspect all lines and connections for sharp bends or damage. 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. To check airtightness of fuel tank and fuel inlet pipe, disconnect EVAP line hose from charcoal canister. Repeat step 1. (Scheme 186) EVAP canister is located near fuel tank. (Scheme 159) Apply.58 psi (.040 kg/cm 2 ) air pressure to EVAP line hose so that the pressure inside the fuel tank is.58 psi (.040 kg/cm 2 ). Check that pressure inside the fuel tank will hold steady for one minute.
3. If pressure inside the fuel tank will hold steady for one minute, reinstall EVAP line hose on charcoal canister. Go to next step. If pressure inside the fuel will not hold steady for one minute, check for leaking hoses or pipes at fuel tank and fuel inlet pipe, or for leaks at the fuel tank. If no leaks exist, replace fuel tank and fuel inlet pipe. Reinstall EVAP line hose on charcoal canister. Go to next step.
4. To check overfill check valve and cut-off valve, disconnect purge line hose and EVAP line hose from charcoal canister, and install cap on air drain hose. Repeat step 2. (Scheme 186)
5. Apply.58 psi (.040 kg/cm 2 ) air pressure to purge line hose fitting on charcoal canister. Repeat step 2. (Scheme 186) 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 the overfill check valve is may be closed. Ensure fuel tank is not full of fuel when checking for airflow at EVAP line hose.
6. 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, purge 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 159)
7. To check air inlet line, disconnect air inlet line hose from charcoal canister. Repeat step 3. (Scheme 186) 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.
8. Remove charcoal canister. (Scheme 159) Inspect charcoal canister for cracks or damage.
9. Install cap on vent port on charcoal canister. (Scheme 187) Apply.26 psi (.018 kg/cm 2 ) air pressure to EVAP port while holding purge port closed. (Scheme 187) Ensure air flows freely from air drain port.
10. Apply.26 psi (.018 kg/cm 2 ) air pressure to EVAP port while holding air drain port and purge port closed. (Scheme 187) Ensure no air flows from air inlet port.
11. Using vacuum pump, apply 1.01 in. Hg of vacuum to purge port. Ensure vacuum does not decrease when air inlet port is closed, and that vacuum decreases when air inlet port is opened.
12. While holding air inlet port closed, use vacuum pump to apply 1.01 in. Hg of vacuum to EVAP port. Ensure air flows into purge port. Replace charcoal canister if defective.

Scheme 186

Scheme 187

1. Manufacturer provides testing information for checking airtightness of fuel tank and components along with testing of charcoal canister. Inspect all lines and connections for sharp bends or damage. 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. To check airtightness of fuel tank and fuel inlet pipe, note location of lines on charcoal canister. Repeat step 1. (Scheme 188) EVAP canister is located near fuel tank. (Scheme 161) Disconnect EVAP line hose from charcoal canister.
3. Apply.58 psi (.040 kg/cm 2 ) air pressure to EVAP line hose so that the pressure inside the fuel tank is.58 psi (.040 kg/cm 2 ). Repeat step 2. (Scheme 188) Check that pressure inside the fuel tank will hold steady for one minute.
4. If pressure inside the fuel tank will hold steady for one minute, reinstall EVAP line hose on charcoal canister. Go to next step. If pressure inside the fuel will not hold steady for one minute, check for leaking hoses or pipes at fuel tank and fuel inlet pipe, or for leaks at the fuel tank. If no leaks exist, replace fuel tank and fuel inlet pipe. Reinstall EVAP line hose on charcoal canister. Go to next step.
5. To check overfill check valve and cut-off valve, disconnect purge line hose and EVAP line hose from charcoal canister, and install cap on air drain hose and EVAP port. Repeat step 3. (Scheme 188) It may be necessary to pull drain hose from sub-frame for installation of the cap.
6. Apply.58 psi (.040 kg/cm 2 ) air pressure to purge port on charcoal canister. Repeat step 4. (Scheme 188) Ensure air flows from EVAP line hose when air pressure is applied to purge port on charcoal canister.
7. 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 161)
8. To check air inlet line, disconnect air inlet hose from charcoal canister. Repeat step 5. (Scheme 188) Apply air pressure to air inlet hose. Air should flow through air inlet hose. If air flows through air inlet hose, go to next step. If air does not flow through air inlet hose, check for restricted air inlet hose or air inlet line.
9. Remove charcoal canister. (Scheme 161) See appropriate N - REMOVE/INSTALL/OVERHAUL article. Inspect charcoal canister for cracks or damage.
10. Install hose and cap on vent port on charcoal canister. (Scheme 189) Apply.26 psi (.018 kg/cm 2 ) air pressure to port "A" while holding port "B" closed. (Scheme 189) Ensure air flows freely from port "D".
11. Apply.26 psi (.018 kg/cm 2 ) air pressure to port "A" while holding ports "B" and "D" closed. (Scheme 189) Ensure no air flows from port "C".
12. Using vacuum pump, apply 1.01 in. Hg of vacuum to port "B". (Scheme 189) Ensure vacuum does not decrease when air port "C" is closed, and that vacuum decreases when port "C" is opened.
13. While holding port "C" closed, use vacuum pump to apply 1.01 in. Hg of vacuum to port "A". Ensure air flows into port "B". Replace charcoal canister if defective.

Scheme 188

Scheme 189

EVAP Vacuum Switching Valve (Camry & Corolla)

For testing of EVAP VSV, see EVAP VACUUM SWITCHING VALVE under FUEL EVAPORATION SYSTEM.

Vapor Pressure Sensor (Camry & Corolla)

For testing of vapor pressure sensor, see VAPOR PRESSURE SENSOR under FUEL EVAPORATION SYSTEM.

Vapor Pressure Sensor Vacuum Switching Valve (Camry & Corolla)

For testing of vapor pressure sensor, see VAPOR PRESSURE SENSOR VACUUM SWITCHING VALVE under FUEL EVAPORATION SYSTEM.

POSITIVE CRANKCASE VENTILATION (PCV)

1. Remove PCV valve. Apply air pressure to PCV valve at cylinder head side of PCV valve. Ensure air flows easily through PCV valve.
2. 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.

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in appropriate D - ADJUSTMENTS article.
2. Shut engine off. Disconnect and plug vacuum hose at throttle opener. (Scheme 190) Start engine. Maintain engine speed at 2500 RPM. Release throttle and note engine speed. Engine speed should be 1300-1500 RPM.
3. If engine speed is not within specification, loosen lock nut (if equipped) and rotate throttle opener adjusting screw until correct engine speed is obtained. (Scheme 191) Tighten lock nut (if equipped). Reinstall vacuum hose on throttle opener.

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in appropriate D - ADJUSTMENTS article.
2. Shut engine off. Disconnect and plug vacuum hose at throttle opener. (Scheme 192) Start engine and note engine speed. Engine speed should be 1200-1500 RPM.
3. If engine speed is not within specification, replace throttle body. Shut engine off. Reinstall vacuum hose on throttle opener. Start engine and ensure engine returns to proper idle speed.

Scheme 190

Scheme 191

Scheme 192