Engine Controls - System & Component Testing - 4-CYLINDER: Other Toyota 4Runner III

Power & Ground Circuits

For testing of Engine Control Module (ECM) power and ground circuits, see PIN VOLTAGE CHARTS article. See ECM LOCATION table for identifying ECM mounting locations.

ECM LOCATION

Scheme 107

1. Disconnect electrical connector for A/C compressor lock sensor. A/C compressor lock sensor is located near front of A/C compressor and electrical connector is located near generator. (Scheme 107) This is the electrical connector for A/C compressor lock sensor and magnetic clutch on front of A/C compressor.
2. Using ohmmeter, check resistance between terminals No. 1 and 2 on electrical connector for A/C compressor lock sensor. (Scheme 107) Resistance should be 65-125 ohms at 68°F (20°C). Replace A/C compressor lock sensor if resistance is not within specification. It may be necessary to replace A/C compressor along with A/C compressor lock sensor if resistance is not within specification.

AIR/FUEL (A/F) SENSOR

Note. Air/Fuel (A/F) sensor may also be referred to as Air/Fuel (A/F) ratio sensor.

Scheme 108

Scheme 109

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 Engine Control Module (ECM). See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article for retrieving of DTCs.
2. To test 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 108)and (Scheme 109). Replace A/F sensor if resistance is not.8-1.4 ohms at 68°F (20°C).

AIRFLOW METER

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

Tacoma & 4Runner

1. Turn ignition off. Disconnect electrical connector from airflow meter. Airflow meter is located between air intake hose and upper cap on air cleaner assembly. Airflow meter is bolted to upper cap on air cleaner assembly. Note airflow meter terminal identification. (Scheme 110)
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-91238-S05379254692001030600000) 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 ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Ensure electrical connector is installed on airflow meter. Connect voltmeter leads to proper terminals on airflow meter with electrical connector installed. (Scheme 111)
4. Turn ignition on. Apply air into airflow meter and note voltage reading. (Scheme 111) While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate. Remove voltmeter.

Scheme 110

Scheme 111

BRAKELIGHT SWITCH

Note. Brakelight switch may also be referred to as stoplight switch.

Camry, Corolla, Tacoma & 4Runner

1. Disconnect electrical connector at brakelight switch. Brakelight switch is located near top of brake pedal. Note terminal identification on brakelight switch. (Scheme 112)
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.

Scheme 112

Camry Solara, 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 113)
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.

Scheme 113

Camry, Camry Solara, Corolla, RAV4, Tacoma & 4Runner

For testing camshaft position sensor, see CAMSHAFT POSITION SENSOR RESISTANCE under IGNITION CHECKS (DISTRIBUTORLESS IGNITION SYSTEM) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article.

Celica

Camshaft position sensor is a pick-up coil located in the distributor. For testing of pick-up coil, see PICK-UP COIL RESISTANCE and PICK-UP COIL AIR GAP under IGNITION CHECKS (DISTRIBUTOR TYPE IGNITION SYSTEM) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article.

For testing crankshaft position sensor, see CRANKSHAFT POSITION SENSOR RESISTANCE under IGNITION CHECKS (DISTRIBUTORLESS IGNITION SYSTEM) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article.

For testing crankshaft position sensor, see CRANKSHAFT POSITION SENSOR RESISTANCE under IGNITION CHECKS (DISTRIBUTOR TYPE IGNITION SYSTEM) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article.

1. EGR gas temperature sensor is located near EGR valve. Remove EGR gas temperature sensor. See ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER 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-91238-S29729646532001030600000) 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-91238-S24112892392001030600000) table. Remove ECT sensor. See ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER 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 114) Replace ECT sensor if resistance is not within specification.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR LOCATION

Scheme 114

HEATED OXYGEN SENSOR

See OXYGEN SENSOR .

Camry, Camry Solara, Celica, Corolla & RAV4

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 electrical terminals on intake air temperature sensor.
3. Heat water and note that resistance is within specification in relation to temperature. (Scheme 114) Replace intake air temperature sensor if resistance is not within specification.

KNOCK SENSOR

Note. Knock sensor may also be referred to as knock sensor No. 1.

1. Knock sensor is located on side of cylinder block. (Scheme 115)- (Scheme 119). Manufacturer recommends removing knock sensor from cylinder block before testing. See ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER 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 115

Scheme 116

Scheme 117

Scheme 118

Scheme 119

1. Ensure ignition is off. To test MAP sensor supply voltage, disconnect electrical connector from MAP sensor. See «MAP SENSOR LOCATION»(ref-91238-S36988700422001030600000) table. (Scheme 120)- (Scheme 123). MAP SENSOR LOCATION Application Location Camry & Camry Solara 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
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 124) 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 WIRING DIAGRAMS article. If MAP sensor supply voltage is within specification, turn ignition off. Reinstall electrical connector on MAP sensor.
4. On Camry, Camry Solara, Celica and RAV4, 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 Engine Control Module (ECM) terminals E2 and PIM. (Scheme 125)and (Scheme 126). See «ECM LOCATION»(ref-91238-S34985442492001030600000) table. See «ECM TERMINAL APPLICATION»(ref-91238-S01240627532001030600000) table. ECM LOCATION Model (1) Location Camry & Camry Solara 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 (1) For illustration of ECM location, see THEORY & OPERATION article. ECM TERMINAL APPLICATION Application & Terminal Wire Color Camry & Camry Solara E2 Brown PIM Black/Yellow Celica E2 Brown PIM Blue Corolla E2 Brown PIM Light Green/Red RAV4 E2 Brown PIM Light Green/Black
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-91238-S42927545482001030600000) table. Replace MAP sensor if output voltage drop is not within specification.

MAP SENSOR OUTPUT VOLTAGE DROP SPECIFICATIONS

Scheme 120

Scheme 121

Scheme 122

Scheme 123

Scheme 124

Scheme 125

Scheme 126

Camry Calif. Emission Vehicles & Camry Solara Calif. Emission Vehicles

1. A heated Air/Fuel (A/F) sensor is mounted on exhaust manifold. For testing of A/F sensor, see «AIR/FUEL (A/F) SENSOR»(ref-91238-S02979487462001030600000). 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 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 127)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 127) 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). See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article for retrieving of DTCs.

Camry Except Calif. Emission Vehicles & Camry Solara Except Calif. Emission Vehicles

1. A heated oxygen sensor is mounted near 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 heater resistance on any oxygen sensor, disconnect electrical connector for appropriate heated oxygen sensor. Electrical connector for bank No. 1 sensor No. 1 is located near upper radiator hose. (Scheme 128) 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 127)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 127)and (Scheme 128). 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 Engine Control Module (ECM). See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article for retrieving of DTCs.

Scheme 127

Scheme 128

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 Engine Control Module (ECM). See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article for retrieving of DTCs.

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.
2. To test heater resistance 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 129) 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 130)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 129)and (Scheme 130). 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 Engine Control Module (ECM). See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article for retrieving of DTCs.

Scheme 129

Scheme 130

RAV4 Calif. Emission Vehicles

1. A heated Air/Fuel (A/F) sensor is mounted on exhaust manifold. For testing of A/F sensor, see «AIR/FUEL (A/F) SENSOR»(ref-91238-S02979487462001030600000). 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 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 131)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 131) 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). See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article for retrieving of DTCs.

RAV4 Except Calif. Emission Vehicles

1. Heated oxygen sensor is mounted near 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 heater resistance 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 132) 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 131)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 131)and (Scheme 132). 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 Engine Control Module (ECM). See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article for retrieving of DTCs.

Scheme 131

Scheme 132

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 heater resistance on any oxygen sensor, disconnect electrical connector for appropriate heated oxygen sensor. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 133)- (Scheme 136). 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 Engine Control Module (ECM). See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article for retrieving of DTCs.

Scheme 133

Scheme 134

Scheme 135

Scheme 136

A/T Models

1. Disconnect electrical connector from PNP switch. The PNP switch is mounted on side of transmission/transaxle. Note terminal identification. (Scheme 137)
2. Using ohmmeter, check for continuity between specified terminals with shift lever in proper positions. See «PARK/NEUTRAL POSITION SWITCH SPECIFICATIONS»(ref-91238-S12676259732001030600000) table. If proper continuity does not exist, adjust or replace switch as necessary.

PARK/NEUTRAL POSITION SWITCH SPECIFICATIONS

Scheme 137

Pick-up coil may also be referred to as a camshaft position sensor. For testing of pick-up coil, see PICK-UP COIL RESISTANCE and PICK-UP COIL AIR GAP under IGNITION CHECKS (DISTRIBUTOR TYPE IGNITION SYSTEM) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article.

Camry, Camry Solara & Corolla

Power steering pressure switch is located on power steering pump, near the pressure hose. Testing information is not available from manufacturer.

Camry, Camry Solara, Celica, Corolla, Tacoma & 4Runner

1. Ensure ignition is off. Disconnect electrical connector from Throttle Position (TP) sensor on throttle body. Note terminal identification on TP sensor. (Scheme 138)- (Scheme 141).
2. On Camry, Camry Solara, Celica, Tacoma and 4Runner, disconnect vacuum hose and apply vacuum to throttle opener. (Scheme 138)- (Scheme 141).
3. On all models, using ohmmeter, check resistance between specified terminals in relation to throttle position. See «TP SENSOR RESISTANCE SPECIFICATIONS»(ref-91238-S15160653462001030600000) 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. Disconnect vacuum hose and apply vacuum to throttle opener.
2. Using ohmmeter, check resistance between specified terminals in relation to throttle position. See «TP SENSOR RESISTANCE SPECIFICATIONS»(ref-91238-S15160653462001030600000) table. Replace components as necessary if resistance is not within specification.

TP SENSOR RESISTANCE SPECIFICATIONS

Scheme 138

Scheme 139

Scheme 140

Scheme 141

VAPOR PRESSURE SENSOR

See VAPOR PRESSURE SENSOR under FUEL EVAPORATIVE SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS.

Scheme 142

Scheme 143

Scheme 144

1. Vehicle speed sensor is mounted on transaxle and contains a 3-pin electrical connector. (Scheme 142) Connect voltmeter positive lead to terminal No. 3 (outer terminal) and negative lead to terminal No. 2 (center terminal) on vehicle speed sensor. (Scheme 143)and (Scheme 144).
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 vehicle speed sensor. (Scheme 143)and (Scheme 144).
3. While rotating vehicle speed sensor shaft, ensure voltage changes from zero volts to at least 11 volts. Voltage should change 4 times per revolution of the shaft. Replace vehicle speed sensor if voltage does not change as specified. Remove test equipment.

Scheme 145

Scheme 146

Scheme 147

1. Vehicle speed sensor is mounted near rear of transmission or transfer case and contains a 3-pin electrical connector. (Scheme 145) On Tacoma, electrical connector contains Blue, Green/Red and Pink wires. On 4Runner, electrical connector contains Black/Yellow, Pink/Blue and Gray/Blue wires.
2. On all models, connect voltmeter positive lead to terminal No. 3 (outer terminal) and negative lead to terminal No. 2 (center terminal) on vehicle speed sensor. (Scheme 144), (Scheme 146) and (Scheme 147).
3. Using jumper wires, connect positive battery terminal to terminal No. 1 (outer terminal) and negative battery terminal to terminal No. 2 (center terminal) on vehicle speed sensor. (Scheme 144), (Scheme 146) and (Scheme 147).
4. While rotating vehicle speed sensor shaft, ensure voltage changes from zero volts to at least 11 volts. Voltage should change 4 times per revolution of the shaft. Replace vehicle speed sensor if voltage does not change as specified. Remove test equipment.

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-91238-S10051279582001030600000) table. (Scheme 148)- (Scheme 153). CIRCUIT OPENING RELAY LOCATION (1) Application Location Camry & Camry Solara 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 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.
2. To test circuit opening relay continuity, use ohmmeter to check for continuity and no continuity between specified terminals on circuit opening relay. (Scheme 154)- (Scheme 158).
3. To test circuit opening relay operation, apply battery voltage and ground to circuit opening relay and use ohmmeter to check for continuity between specified terminals on circuit opening relay. (Scheme 154)- (Scheme 158). Replace circuit opening relay if defective.

Scheme 148

Scheme 149

Scheme 150

Scheme 151

Scheme 152

Scheme 153

Scheme 154

Scheme 155

Scheme 156

Scheme 157

Scheme 158

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-91238-S04799733232001030600000) table. EFI MAIN RELAY LOCATION Application Location Camry, Camry Solara & Celica In Fuse/Relay Box At Driver's Side Front Corner Of Engine Compartment, Near Battery 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, Or In Fuse/Relay Box At Driver's Side Front Corner Of Engine Compartment Tacoma & 4Runner In Fuse/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 158)- (Scheme 160).
3. To test EFI main relay operation, apply battery voltage and ground to EFI main relay and use ohmmeter to check for continuity between specified terminals on EFI main relay. (Scheme 158)- (Scheme 160). Replace EFI main relay if defective.

Scheme 159

Scheme 160

See CIRCUIT OPENING RELAY under RELAYS.

See EFI MAIN RELAY under RELAYS.

Fuel Pump Pressure

For fuel pump pressure testing, see FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article.

Fuel Injectors (Camry, Camry Solara & RAV4)

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-91238-S29590857772001030600000) table.
2. To check fuel injector volume, remove fuel injector. See FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER 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 from Fuel Injector Measuring Set (SST 09268-41047) on top of fuel filter. (Scheme 161) 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 from fuel injector measuring set, connect fuel injector to delivery hose. (Scheme 161)
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 No. 3. (Scheme 165), (Scheme 166) and (Scheme 169). 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-91238-S36686034282001030600000).
7. Connect Fuel Injector Tester (09842-30070) to fuel injector for 15 seconds. (Scheme 172) 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-91238-S10985300492001030600000) table. Ensure difference between fuel injector volume on all fuel injectors is within specification. See «FUEL INJECTOR VOLUME SPECIFICATIONS»(ref-91238-S10985300492001030600000) 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-91238-S38830359822001030600000) 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 & 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-91238-S29590857772001030600000) table.
2. To check fuel injector volume, remove fuel injector. See FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Ensure area around fuel hoses on fuel filter is clean. Remove union bolts with gaskets, and disconnect fuel hose from fuel filter. (Scheme 162)and (Scheme 163).
3. Install union, delivery hose, gaskets and union bolt from Fuel Injector Measuring Set (SST 09268-41047) on fuel filter. (Scheme 162)and (Scheme 163). 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 from fuel injector measuring set, connect fuel injector to delivery hose. (Scheme 162)and (Scheme 163).
5. Remove fuel pressure regulator from fuel rail. See FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Using NEW "O" ring, install union on fuel pressure regulator. (Scheme 162)and (Scheme 163). 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 data link connector No. 3. (Scheme 167), (Scheme 170) and (Scheme 171). 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-91238-S36686034282001030600000).
8. Connect Fuel Injector Tester (09842-30070) to fuel injector for 15 seconds. (Scheme 172) 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-91238-S10985300492001030600000) table. Ensure difference between fuel injector volume on all fuel injectors is within specification. See «FUEL INJECTOR VOLUME SPECIFICATIONS»(ref-91238-S10985300492001030600000) 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-91238-S38830359822001030600000) 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-91238-S29590857772001030600000) table.
2. To check fuel injector volume, remove fuel injector. See FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Remove fuel pipe clamp from end of fuel pipe at end of fuel rail if not previously done. Perform STEP 1. (Scheme 173) Ensure area around fuel pipe and disconnect fitting is clean.
3. Depress both sides of retainer and pull fuel pipe with disconnect fitting from fuel pipe fitting. Perform STEP 2. (Scheme 173)
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 164) Ensure fuel pipe connector is securely attached on fuel pipe fitting and retainer is fully seated.
5. Connect delivery hose from Fuel Injector Measuring Set (SST 09268-41047) to fuel pipe connector. Check that grommet and "O" ring are installed on top of fuel injector. Using clamp and union from fuel injector measuring set, connect fuel injector to delivery hose. (Scheme 164)
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 data link connector No. 3. (Scheme 168) 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-91238-S36686034282001030600000).
8. Connect Fuel Injector Tester (09842-30080) to fuel injector for 15 seconds. (Scheme 172) 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-91238-S10985300492001030600000) table. Ensure difference between fuel injector volume on all fuel injectors is within specification. See «FUEL INJECTOR VOLUME SPECIFICATIONS»(ref-91238-S10985300492001030600000).
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-91238-S38830359822001030600000) table. Replace fuel injector if leakage exceeds specified amount. Disconnect negative battery cable. Remove test equipment.
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 old retainer. Pull on fuel pipe to ensure fuel pipe is properly locked on 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

FUEL INJECTOR VOLUME SPECIFICATIONS

FUEL INJECTOR LEAKAGE SPECIFICATIONS

Scheme 161

Scheme 162

Scheme 163

Scheme 164

Scheme 165

Scheme 166

Scheme 167

Scheme 168

Scheme 169

Scheme 170

Scheme 171

Scheme 172

Scheme 173

Fuel Cut System

1. Connect scan tool to data link connector No. 3. (Scheme 165)- (Scheme 171). 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 RPM to specified RPM. See «FUEL CUT SYSTEM TESTING SPEED»(ref-91238-S26158532622001030600000) table. FUEL CUT SYSTEM TESTING SPEED Application Engine RPM Camry, Camry Solara & Celica 2500 Corolla 3500 RAV4 2500 Tacoma & 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 SYSTEM SPECIFICATIONS»(ref-91238-S36315683842001030600000) table. Shut engine off. Remove test equipment.

FUEL CUT SPECIFICATIONS (1)

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

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS - 4-CYLINDER 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 No. 1. (Scheme 174)- (Scheme 178). See «DATA LINK CONNECTOR NO. 1 LOCATIONS»(ref-91238-S26884576182001030600000) table. DATA LINK CONNECTOR NO. 1 LOCATIONS Application Location Camry & Camry Solara Passenger's Side Of Engine Compartment, Near Strut Tower Celica Driver's Side Rear Corner Of Engine Compartment, Near Brake Booster RAV4 On Timing Belt End Of Engine, Above Generator Tacoma & 4Runner On End Of Intake Manifold At Front Of Engine
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-91238-S34388534572001030600000) table. IAC VALVE ENGINE SPEED TESTING SPECIFICATIONS Application Engine RPM Camry, Camry Solara, Celica & RAV4 900-1300 Tacoma & 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 179)- (Scheme 182).
6. Replace IAC valve if resistance is not within specification. See «IAC VALVE RESISTANCE SPECIFICATIONS»(ref-91238-S13613604502001030600000) table. IAC VALVE RESISTANCE SPECIFICATIONS Application Ohms Camry, Camry Solara, Celica, RAV4, Tacoma & 4Runner 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 FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Apply battery voltage to +B terminal on IAC valve. (Scheme 183)- (Scheme 185). Apply battery ground terminal to proper terminal and ensure valve opens and closes. (Scheme 183)- (Scheme 185). 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»(ref-91238-S03219977852001030600000) table. See appropriate wiring diagram in WIRING DIAGRAMS article.

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS - 4-CYLINDER 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 data link connector No. 1. (Scheme 186) Data link connector No. 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 FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Check that valve on inside of IAC valve is half open. (Scheme 187) Reinstall electrical connector on IAC valve.
5. Disconnect electrical connector from Engine Coolant Temperature (ECT) sensor. ECT sensor is located on flywheel end of cylinder head below ignition coil and contains a Dark Gray 2-pin electrical connector with White and 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 187)
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 ECM and IAC valve. See «ECM LOCATION»(ref-91238-S03219977852001030600000) table. See appropriate wiring diagram in WIRING DIAGRAMS article. If wiring circuit and ECM are okay, replace IAC valve.

ECM LOCATION

Scheme 174

Scheme 175

Scheme 176

Scheme 177

Scheme 178

Scheme 179

Scheme 180

Scheme 181

Scheme 182

Scheme 183

Scheme 184

Scheme 185

Scheme 186

Scheme 187

THROTTLE BODY

Note. Following procedure is for checking vacuum supply at throttle body.

1. Start engine and allow engine to idle. Note vacuum port location on throttle body. (Scheme 188)- (Scheme 191).
2. Check that vacuum and no vacuum exist at specified vacuum ports on throttle body with engine idling and with engine at more than idle. See «THROTTLE BODY VACUUM SUPPLY»(ref-91238-S31504153212001030600000) table. Repair or replace components if vacuum supply is not as designated.

THROTTLE BODY VACUUM SUPPLY

Scheme 188

Scheme 189

Scheme 190

Scheme 191

Manufacturer does not provide procedure for checking vacuum supply at throttle body.

IGNITION SYSTEM

Note. For basic ignition checks, see IGNITION CHECKS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article.

See KNOCK SENSOR under ENGINE SENSORS & SWITCHES.

Scheme 192

Scheme 193

Scheme 194

Scheme 195

Scheme 196

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).
2. Reinstall filter and cap. Using 3-way connector, install vacuum gauge in vacuum hose between top of EGR valve and EGR vacuum modulator. Perform STEP 1. (Scheme 197) 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 data link connector No. 3. (Scheme 170)and (Scheme 171). 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 EGR valve. Perform STEP 2. (Scheme 197) This 3-way connector and small vacuum hose goes from EGR valve and EGR vacuum modulator to EGR VSV. Install plug in vacuum hose to EGR VSV.
7. Connect vacuum hose from port "Q" on EGR vacuum modulator to directly to EGR valve. see scheme 98 This will by-pass 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. Start engine. 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 197

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

1. Remove EGR check valve. (Scheme 196) 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 monitor engine RPM by using scan tool. Scan tool may be connected to data link connector No. 3 for monitoring engine RPM. (Scheme 165)- (Scheme 171).

1. Mark vacuum hose locations and disconnect vacuum hoses from EGR vacuum modulator. (Scheme 192)- (Scheme 196). Block ports "P" and "R" on EGR vacuum modulator. see scheme 98 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". see scheme 98 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-91238-S28085304252001030600000) 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

Scheme 198

1. Disconnect electrical connector from EGR VSV. See «EGR VSV LOCATIONS»(ref-91238-S12027058222001030600000) table. (Scheme 192), (Scheme 193) and (Scheme 195). 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 body of EGR VSV.
3. To test EGR VSV operation, apply air pressure to port "E". Ensure air flows from port "G". Perform STEP 1. (Scheme 198) 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". Perform STEP 2. (Scheme 198) Replace EGR VSV if defective.

Scheme 199

1. Disconnect electrical connector from EGR VSV. See «EGR VSV LOCATIONS»(ref-91238-S12027058222001030600000) table. (Scheme 196) 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 body. Replace EGR VSV if continuity exists between electrical terminal and body of EGR VSV.
3. To test EGR VSV operation, apply air pressure to port "E". Ensure no air flows from port "F". Perform STEP 1. (Scheme 199) Apply battery voltage and ground to electrical terminals on EGR VSV.
4. Apply air pressure to port "E". Ensure air flows from port "F". Perform STEP 2. (Scheme 199) Replace EGR VSV if defective.

EGR VSV LOCATIONS

1. Remove EGR valve. See EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER 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 Evaporative (EVAP) system may contain different components depending on application. (Scheme 192)- (Scheme 196). When testing fuel EVAP system components, it may be necessary to use proper illustration to determine component location.

Note. On Camry, Camry Solara, Celica and Corolla, an On-Board Refilling Vapor Recovery (ORVR) system is used to recover fuel vapors into charcoal canister that are generated during refueling. ORVR system consists of fuel inlet pipe, overfill check valve, cut-off valve and charcoal canister. (Scheme 192)- (Scheme 194). 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 fuel EVAP system and ORVR system, see appropriate FUEL EVAP SYSTEM TEST.

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

Charcoal Canister

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

Cut-Off Valve (Camry, Camry Solara, Celica & Corolla)

Individual component testing is not available from manufacturer. Manufacturer provides testing information for testing airtightness of fuel tank and components along with testing of charcoal canister, cut-off valve and fuel EVAP system. See appropriate FUEL EVAP SYSTEM TEST.

EVAP Vacuum Switching Valve

1. Remove EVAP Vacuum Switching Valve (VSV). See «EVAP VSV LOCATION»(ref-91238-S40273054992001030600000) table. (Scheme 192)- (Scheme 196). EVAP VSV LOCATION Application Location Camry & Camry Solara On Bracket Near Air Filter Housing & Driver's Side Strut Tower, & Contains Black 2-Pin Electrical Connector With Violet/White & Black/Yellow Wires Celica On Bracket Near Air Filter Housing & Driver's Side Strut Tower, & Contains Black 2-Pin Electrical Connector With Light Green/Black & Black/Red Wires Corolla On Bracket At Rear Of Air Filter Housing & Contains Black 2-Pin Electrical Connector With Blue/Black & Black Wires RAV4 On Bracket Near Rear Of Air Filter Housing & Contains Black 2-Pin Electrical Connector With Black/Red & Pink Wires Tacoma Bolted To End Of Charcoal Canister & Contains Black 2-Pin Electrical Connector With White/Red & White/Green Wires 4Runner Bolted To End Of Charcoal Canister & Contains Black 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-91238-S22271613222001030600000) table. Replace EVAP VSV if no continuity exists or resistance is not within specification. EVAP VSV RESISTANCE Application Ohms @ 68°F (20°C) Camry, Camry Solara & Celica 30-34 Corolla 27-33 RAV4, Tacoma & 4Runner 30-34
3. 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.
4. To test EVAP VSV operation, apply air pressure to port "E". Ensure air does not flow from port "F". Perform STEP 1. (Scheme 200)
5. 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 200) Replace EVAP VSV if defective.

Scheme 200

Overfill Check Valve (Camry, Camry Solara, Celica & Corolla)

Individual component testing is not available from manufacturer. Manufacturer provides testing information for testing airtightness of fuel tank and components along with testing of charcoal canister, overfill check valve and fuel EVAP system. See appropriate FUEL EVAP SYSTEM TEST.

Scheme 201

Scheme 202

Scheme 203

Scheme 204

Scheme 205

1. Ensure ignition is off. To test vapor pressure sensor supply voltage, disconnect electrical connector from vapor pressure sensor. See «VAPOR PRESSURE SENSOR LOCATION»(ref-91238-S07764919742001030600000) table. (Scheme 192)- (Scheme 196). VAPOR PRESSURE SENSOR LOCATION Application Location Camry On Charcoal Canister, Near Fuel Tank & Contains Black 3-Pin Electrical Connector With Brown, Pink & Yellow Wires Camry Solara On Charcoal Canister, Near Fuel Tank & Contains Black 3-Pin Electrical Connector With Blue/Red, Brown & 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, Yellow & Blue/Yellow Wires Tacoma On Firewall, Above Brake Booster & Contains Black 3-Pin Electrical Connector With Brown/Black, Green/Yellow & Red/Yellow Wires 4Runner On Firewall, Above Brake Booster & Contains Black 3-Pin Electrical Connector With Blue/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 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 201)- (Scheme 205). Obtain access to Engine Control Module (ECM). See «ECM LOCATION»(ref-91238-S16300150832001030600000) table. ECM LOCATION Model (1) Location Camry & Camry Solara 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 & 4Runner Behind Glove Box (1) For illustration of ECM location, see THEORY & OPERATION article.
5. Connect voltmeter between specified ECM terminals. (Scheme 206)- (Scheme 208). See «ECM TERMINAL APPLICATION»(ref-91238-S25765637742001030600000) table. ECM TERMINAL APPLICATION Application & Terminal Wire Color Camry E2 Brown PTNK Pink Camry Solara E2 Brown PTNK (1) 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 4Runner E2 Brown/Black PTNK Light Green/Black (1) Wire is a Blue/Red wire at vapor pressure sensor and turns to a Pink wire at ECM.
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-91238-S28034794282001030600000) table.
7. Release vacuum from vapor pressure sensor. Ensure output voltage is within specification. See «VAPOR SENSOR OUTPUT VOLTAGE»(ref-91238-S28034794282001030600000) 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-91238-S28034794282001030600000) table. Replace vapor sensor if output voltage is not within specification. Reconnect vacuum hose.

VAPOR SENSOR OUTPUT VOLTAGE

Scheme 206

Scheme 207

Scheme 208

Vapor Pressure Sensor Vacuum Switching Valve

1. Remove vapor pressure sensor Vacuum Switching Valve (VSV). See «VAPOR PRESSURE SENSOR VSV LOCATION»(ref-91238-S24447736142001030600000) table. (Scheme 192)- (Scheme 196). VAPOR PRESSURE SENSOR VSV LOCATION Application Location Camry, Camry Solara, Celica & Corolla On Charcoal Canister, Near Fuel Tank RAV4, Tacoma & 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-91238-S38427888952001030600000) 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, Camry Solara & Celica 33-39 Corolla 37-44 RAV4 33-39 Tacoma & 4Runner 37-44
3. Ensure no continuity exists between each electrical terminal and 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". Perform STEP 1. (Scheme 209)
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". Perform STEP 2. (Scheme 209) Replace vapor pressure sensor VSV if defective.

Scheme 209

POSITIVE CRANKCASE VENTILATION (PCV)

1. Remove PCV valve. (Scheme 192)- (Scheme 196). 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.

Camry, Camry Solara, Celica & RAV4

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS - 4-CYLINDER article.
2. Shut engine off. Disconnect and plug vacuum hose at throttle opener. (Scheme 210) Start engine. Maintain engine speed at 2500 RPM. Release throttle and note engine speed. Engine speed should be 1300-1500 RPM with electric cooling fan off.
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 211) Tighten lock nut (if equipped). Reinstall vacuum hose on throttle opener.

Scheme 210

Scheme 211

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS - 4-CYLINDER article.
2. Shut engine off. Disconnect and plug vacuum hose at throttle opener. (Scheme 212) 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 212