Engine Controls - System & Component Testing - 4-CYLINDER: Other Toyota MR2 W30

PRIUS

The following service precautions must be followed

Scheme 318

1. Ensure ignition is off and ignition key is removed from ignition before performing any inspection or service procedure in engine compartment, as engine may automatically start and shut off when ignition is on and READY light is illuminated. READY light is displayed just above the shift lever position indicator on instrument cluster at center of instrument panel.
2. Read all service and warning labels in engine compartment before performing any procedures in engine compartment.
3. All high-voltage wiring harness connectors contain Orange connectors. DO NOT touch any wiring harness that contains Orange connectors.
4. High-voltage battery and other high-voltage components may be identified by HIGH VOLTAGE caution labels on them. DO NOT touch these components.
5. If necessary to inspect or service high-voltage system, ensure ignition is off. Remove service plug and wait at least 5 minutes to ensure high voltage is fully discharged before touching any high-voltage wiring harness, connectors or components. Service plug is located on service plug assembly at driver's side front corner of trunk compartment, near high-voltage battery. (Scheme 318) Ensure service plug is stored in a location in which no one may install service plug while technician is working on the vehicle.
6. If necessary to touch any high-voltage wiring harness, connectors or components, ensure service plug is removed and battery voltage or less exists at electrical connector. Use Toyota insulated gloves when touching any high-voltage wiring harness, connectors or components. Ensure insulated gloves are dry and in good condition and that no holes exist in insulated gloves by applying air to insulated glove before touching any high-voltage wiring harness, connectors or components.
7. DO NOT wear any metal objects while working on vehicle which may accidently drop and cause a short circuit.
8. If any high-voltage wiring harness connector is disconnected, ensure terminal on wiring harness connector is wrapped with tape to prevent wiring harness connector from contacting any surface.
9. If servicing high-voltage system, place sign on roof of vehicle to indicate to other technicians that high-voltage system is being serviced.

ENGINE CONTROL SYSTEM

For engine control system component locations (Scheme 319)- (Scheme 328).

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ENGINE CONTROL MODULE

For ECM location (Scheme 329)- (Scheme 338).

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Scheme 338

Camry

Note. Following procedure should be performed if battery is disconnected and reconnected, or battery is discharged and recharged to provide proper automatic operation and jam protection operation of power sun roof.

1. Ensure ignition is on. Depress and hold TILT UP side of power sun roof switch until power sun roof tilts all the way upward and then tilts downward a little. Power sun roof switch is located on headliner, just in front of power sun roof.
2. Check proper operation of open/closing and tilt up/down function for power sun roof using power sun roof switch. Power sun roof should operate anytime ignition is on, or for 43 seconds after ignition is off provided both front doors are closed. It will stop operating if any front door is opened. Depressing SLIDE OPEN side of power sun roof switch for one second should open power sun roof.
3. Depressing TILT UP side of power sun roof switch for one second should close power sun roof. To tilt power sun roof upward, depress and hold TILT UP side of power sun roof switch for one second. To tilt power sun roof downward, depress and hold SLIDE OPEN side of power sun roof switch for one second.

Celica

Note. Following procedure should be performed if battery is disconnected and reconnected, or battery is discharged and recharged to provide proper automatic operation and jam protection operation of power sun roof.

Close power sun roof using power sun roof switch and continue to depress power sun roof switch briefly after power sun roof is fully closed. Power sun roof switch is located on headliner, just in front of power sun roof.

ACOUSTIC CONTROL INDUCTION SYSTEM VACUUM SWITCHING VALVE (CELICA)

Note. Acoustic Control Induction System (ACIS) Vacuum Switching Valve (VSV) may also be referred to as intake air control valve system VSV.

1. Remove necessary components for access to ACIS VSV. ACIS VSV is located on bottom of air cleaner case. (Scheme 339)
2. Remove ACIS VSV. Using ohmmeter, ensure continuity exists between electrical terminals on ACIS VSV and that resistance is 37-44 ohms at 68°F (20°C). Replace ACIS VSV if no continuity exists or resistance is not within specification.
3. Using ohmmeter, ensure no continuity exists between each electrical terminal and body of ACIS VSV. Replace ACIS VSV if continuity exists between electrical terminal and body of ACIS VSV.
4. To test ACIS VSV operation, apply air pressure to port "E". Ensure air flows from port "G". Perform STEP 1 in illustration. (Scheme 340)
5. Apply battery voltage and ground to electrical terminals on ACIS VSV. Apply air pressure to port "E". Ensure air flows from port "F" and not from port "G". Perform STEP 2 in illustration. (Scheme 340) Replace ACIS VSV if defective. Reinstall ACIS VSV.

Scheme 339

Scheme 340

ELECTRONIC THROTTLE CONTROL SYSTEM

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

Camry, Camry Solara, Celica (VIN "Y"), MR2 With Sequential Manual Transaxle & Prius

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

For A/C compressor lock sensor circuit inspection (Scheme 341)- (Scheme 343).

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Scheme 343

Camry Solara With Manual A/C

For A/C compressor lock sensor circuit inspection (Scheme 344)and (Scheme 346).

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Scheme 346

Testing information is not available from manufacturer.

Highlander

For A/C compressor lock sensor circuit inspection (Scheme 347)and (Scheme 348). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

Scheme 347

Scheme 348

RAV4

Note. For A/C compressor lock sensor circuit diagnostics, see appropriate MANUAL A/C-HEATER SYSTEMS article.

For A/C cut control system circuit inspection (Scheme 349)- (Scheme 351). For engine control module and A/C amplifier location (Scheme 352)

Scheme 349

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A/C EVAPORATOR TEMPERATURE SENSOR CIRCUIT

Note. The A/C Evaporator Temperature Sensor is also referred to as a Thermistor.

For A/C evaporator temperature sensor circuit inspection (Scheme 353)- (Scheme 355).

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Scheme 355

Note. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS .

For A/C evaporator temperature sensor circuit inspection (Scheme 356)- (Scheme 358).

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For A/C evaporator temperature sensor inspection (Scheme 359)

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Corolla & Matrix

For A/C evaporator temperature sensor inspection (Scheme 360)

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ECHO

For A/C evaporator temperature sensor inspection (Scheme 361)

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For A/C evaporator temperature sensor circuit inspection (Scheme 362)- (Scheme 364).

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MR2

For A/C evaporator temperature sensor inspection (Scheme 365)

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For A/C evaporator temperature sensor circuit inspection (Scheme 366)- (Scheme 368).

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For A/C evaporator temperature sensor inspection (Scheme 369)

Scheme 369

Tacoma

For A/C evaporator temperature sensor inspection (Scheme 370)

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ENGINE CONTROL MODULE POWER & GROUND CIRCUITS

For testing of Engine Control Module (ECM) power and ground circuits and identification of ECM electrical connector terminals, see ENGINE CONTROL MODULE POWER SOURCE CIRCUIT . Also see PIN VOLTAGE CHARTS article. For illustration of ECM location, see ENGINE CONTROL MODULE under COMPONENT LOCATIONS.

ENGINE CONTROL MODULE POWER SOURCE CIRCUIT

Note. When performing test for Engine Control Module (ECM) power source circuit, it may be necessary to check wiring harness and components connected to a specified fuse, or check wiring harness and electrical connectors between EFI main relay and battery. For additional wiring information for fuse and power supply circuit, see POWER DISTRIBUTION article in WIRING DIAGRAMS.

For engine control module power source circuit inspection (Scheme 371)- (Scheme 376).

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Camry Solara

For engine control module power source circuit inspection (Scheme 377)- (Scheme 381). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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Scheme 381

For engine control module power source circuit inspection (Scheme 382)- (Scheme 385).

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Corolla

For engine control module power source circuit inspection (Scheme 386)- (Scheme 392). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For engine control module power source circuit inspection (Scheme 393)- (Scheme 396).

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For engine control module power source circuit inspection (Scheme 397)- (Scheme 402). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For engine control module power source circuit inspection (Scheme 403)- (Scheme 408). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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Matrix

For engine control module power source circuit inspection (Scheme 409)- (Scheme 415). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For engine control module power source circuit inspection (Scheme 416)- (Scheme 421). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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Note. Parenthesis are used in RAV4 wiring diagram to indicate different wiring and/or connectors when the vehicle model, engine type or specification is different.

For engine control module power source circuit inspection (Scheme 422)- (Scheme 426). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For engine control module power source circuit inspection (Scheme 427)- (Scheme 431). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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FUEL PUMP CONTROL CIRCUIT

For fuel pump control circuit inspection and wiring diagram (Scheme 432)- (Scheme 437). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For fuel pump control circuit inspection and wiring diagram (Scheme 438)- (Scheme 443). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For fuel pump control circuit inspection and wiring diagram (Scheme 444)- (Scheme 449). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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Note. Manufacturer does not supply circuit diagram for fuel pump control circuit.

For fuel pump control circuit inspection and wiring diagram (Scheme 450)- (Scheme 454). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For fuel pump control circuit inspection and wiring diagram (Scheme 455)- (Scheme 460). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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Scheme 460

Note. Manufacturer does not supply circuit diagram for fuel pump control circuit.

For fuel pump control circuit inspection and wiring diagram (Scheme 461)- (Scheme 465). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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Note. Manufacturer does not supply circuit diagram for fuel pump control circuit.

For fuel pump control circuit inspection and wiring diagram (Scheme 466)- (Scheme 470). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For fuel pump control circuit inspection and wiring diagram (Scheme 471)- (Scheme 476). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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Note. Manufacturer does not supply circuit diagram for fuel pump control circuit.

For fuel pump control circuit inspection and wiring diagram (Scheme 477)- (Scheme 481). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

Scheme 477

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Note. Parenthesis are used in RAV4 wiring diagram to indicate different wiring and/or connectors when the vehicle model, engine type or specification is different.

Note. Manufacturer does not supply circuit diagram for fuel pump control circuit.

For fuel pump control circuit inspection and wiring diagram (Scheme 482)- (Scheme 486). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For fuel pump control circuit inspection and wiring diagram (Scheme 487)- (Scheme 492). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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STARTER MOTOR SIGNAL CIRCUIT

Note. Starter signal circuit is mainly used to increase fuel injection volume during engine starting. Starter signal circuit test is based on the premise that engine cranks normally. If engine will not crank, diagnose by symptom. See SYMPTOMS in TROUBLE SHOOTING - NO CODES article.

For starter signal circuit inspection and wiring diagram (Scheme 493)- (Scheme 498). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For starter signal circuit inspection and wiring diagram (Scheme 499)- (Scheme 503). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For starter signal circuit inspection and wiring diagram (Scheme 504)- (Scheme 510). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For starter signal circuit inspection and wiring diagram (Scheme 511)- (Scheme 514). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For starter signal circuit inspection and wiring diagram (Scheme 515)- (Scheme 519). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For starter signal circuit inspection and wiring diagram (Scheme 520)- (Scheme 523). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For starter signal circuit inspection and wiring diagram (Scheme 524)- (Scheme 527). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For starter signal circuit inspection and wiring diagram (Scheme 528)- (Scheme 530). For Data Link Connector (DLC) location (Scheme 514) Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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Manufacturer does not supply information on starter signal circuit. For location of Data Link Connector (Scheme 531)

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For starter signal circuit inspection and wiring diagram (Scheme 532)- (Scheme 535). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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For starter signal circuit inspection and wiring diagram (Scheme 536)- (Scheme 541). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

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Scheme 541

Camry, Camry Solara, MR2 & Prius

Note. Accelerator pedal position sensor is also referred to as a throttle/pedal position sensor/switch.

For testing of accelerator pedal position sensor, see appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.

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Scheme 546

1. Disconnect electrical connector for A/C compressor lock sensor and magnetic clutch on front of A/C compressor. This is the electrical located near 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 and magnetic clutch. (Scheme 542)- (Scheme 546). Ensure resistance is within specification. See «A/C COMPRESSOR LOCK SENSOR RESISTANCE»(ref-151978-S20564473732003010900000) table. 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 as an assembly. Consult parts department for parts availability. A/C COMPRESSOR LOCK SENSOR RESISTANCE Application Ohms @ 68°F (20°C) Camry 165-205 Camry Solara 65-125 Celica, Highlander, MR2 & RAV4 165-205

A/C EVAPORATOR TEMPERATURE SENSOR

Note. The A/C Evaporator Temperature Sensor is also referred to as a Thermistor.

For A/C evaporator temperature sensor inspection and wiring diagram (Scheme 547)- (Scheme 549).

Scheme 547

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Scheme 549

For A/C evaporator temperature sensor inspection and wiring diagram (Scheme 550)- (Scheme 552).

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For A/C evaporator temperature sensor inspection see scheme 236

For A/C evaporator temperature sensor inspection see scheme 237

For A/C evaporator temperature sensor inspection see scheme 238

For A/C evaporator temperature sensor inspection (Scheme 553)- (Scheme 555).

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Scheme 555

For A/C evaporator temperature sensor inspection see scheme 242

For A/C evaporator temperature sensor inspection (Scheme 556)- (Scheme 558).

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Scheme 558

For A/C evaporator temperature sensor inspection see scheme 246

For A/C evaporator temperature sensor inspection see scheme 247

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

Note. For diagnostic steps that are not listed, see appropriate SELF DIAGNOSTICS article.

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 TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS 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 559)
3. Replace A/F sensor if resistance is not within specification. See «A/F SENSOR HEATER RESISTANCE (CAMRY)»(ref-151978-S32242133962003091800000) table. See «AIR/FUEL SENSOR»(ref-151983-S13377169182003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
4. To check that heater is not shorted, using ohmmeter, check that no continuity exists between E1 and HT terminals on electrical connector. (Scheme 559) Replace A/F sensor if continuity exists. See «REMOVAL & INSTALLATION (CAMRY, CAMRY SOLARA, HIGHLANDER & RAV4)»(ref-151983-S27549482862003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.

A/F SENSOR HEATER RESISTANCE (CAMRY)

Scheme 559

Note. For diagnostic steps that are not listed, see SELF DIAGNOSTICS - CAMRY SOLARA - 4-CYLINDER article.

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 TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS 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 560) Replace A/F sensor if resistance is not within specification. See «A/F SENSOR HEATER RESISTANCE (CAMRY SOLARA)»(ref-151978-S12842625482003091800000) table. See «AIR/FUEL SENSOR»(ref-151983-S13377169182003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.

A/F SENSOR HEATER RESISTANCE (CAMRY SOLARA)

Scheme 560

Highlander & RAV4

1. Two heated A/F sensors are used. Heated A/F sensors are mounted on exhaust manifold above catalytic converters. A/F sensor for cylinders No. 1 and 4 is referred to as bank No. 1 sensor No. 1. A/F sensor for cylinders No. 2 and 3 is referred to as bank No. 2 sensor No. 1. 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 TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS 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 561)and (Scheme 562). Replace A/F sensor if resistance is not within specification. See «A/F SENSOR HEATER RESISTANCE (HIGHLANDER & RAV4)»(ref-151978-S11551952372003091800000) table. See «AIR/FUEL SENSOR»(ref-151983-S13377169182003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.

A/F SENSOR HEATER RESISTANCE (HIGHLANDER & RAV4)

Scheme 561

Scheme 562

Scheme 563

1. Heated A/F sensor is mounted on exhaust pipe in front of 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»(ref-151974-S27066196352003010900000) in appropriate SELF-DIAGNOSTICS 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 563) Replace A/F sensor if resistance is not within specification. See «A/F SENSOR HEATER RESISTANCE (TACOMA)»(ref-151978-S32376423982003010900000) table. See «AIR/FUEL SENSOR»(ref-151983-S13377169182003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article. A/F SENSOR HEATER RESISTANCE (TACOMA) Application & Temperature Ohms 68°F (20°C).8-1.4 1472°F (800°C) 1.8-3.2

AIRFLOW METER

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

1. Remove airflow meter. See «AIRFLOW METER»(ref-151983-S27129553402003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
2. Using ohmmeter, check resistance between terminals E2 and THA on airflow meter. (Scheme 564)- (Scheme 567). Resistance should be within specification in relation to temperature. See «AIRFLOW METER RESISTANCE»(ref-151978-S06069048882003010900000) table. Replace airflow meter if resistance is not within specification. AIRFLOW METER RESISTANCE Application & Temperature Ohms Camry -4°F (-20°C) 13,600-18,400 68°F (20°C) 2210-2690 140°F (60°C) 493-667 Camry Solara, Celica & Corolla -4°F (-20°C) 13,600-18,400 68°F (20°C) 2210-2690 140°F (60°C) 490-670 ECHO (1) Highlander -4°F (-20°C) 13,600-18,400 68°F (20°C) 2210-2690 140°F (60°C) 493-667 MR2, Matrix, Prius & RAV4 -4°F (-20°C) 13,600-18,400 68°F (20°C) 2210-2690 140°F (60°C) 490-670 Tacoma -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 (1) For Air Flow Meter testing, see appropriate SELF-DIAGNOSTICS article.
3. Airflow meter operation should be checked. On Camry and Highlander, go to next step. On Camry Solara, Celica, Corolla, ECHO, MR2, Prius, RAV4 and Tacoma, go to step 5.
4. Apply battery voltage to +B terminal on airflow meter and battery ground to E2G terminal on airflow meter. (Scheme 564) Connect voltmeter leads to proper terminals on airflow meter. (Scheme 564) Apply air into designated area on airflow meter and note voltage reading. (Scheme 564) While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate.
5. Install electrical connector on airflow meter. Connect voltmeter leads to proper terminals on airflow meter with electrical connector installed. (Scheme 568)- (Scheme 570). Turn ignition on. Apply air into designated area on airflow meter and note voltage reading. (Scheme 564)and (Scheme 568) - (Scheme 570). While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate. Turn ignition off. Remove voltmeter.

Scheme 564

Scheme 565

Scheme 566

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Scheme 569

Scheme 570

BRAKELIGHT SWITCH

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

Camry, Camry Solara & Highlander

1. Disconnect electrical connector at brakelight switch. Brakelight switch is located near top of brake pedal. Note terminal identification on brakelight switch. (Scheme 571)
2. Using ohmmeter, check that continuity exists between terminals No. 1 and 2 with brake pedal depressed so pin on brakelight switch is extended. Check that no continuity exists between terminals No. 1 and 2 with brake pedal released so pin on brakelight switch is pushed in.
3. Check that no continuity exists between terminals No. 3 and 4 with brake pedal depressed so pin on brakelight switch is extended. Check that continuity exists between terminals No. 3 and 4 with brake pedal released so pin on brakelight switch is pushed in. Adjust or replace brakelight switch if operation is not as described. See «BRAKELIGHT SWITCH»(ref-151983-S37773445542003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.

Scheme 571

Celica, Corolla, Matrix, MR2, RAV4 & Tacoma

1. Disconnect electrical connector at brakelight switch. Brakelight switch is located near top of brake pedal. Note terminal identification on brakelight switch. (Scheme 572)
2. On models without cruise control, using ohmmeter, check that no continuity exists between terminals No. 1 and 2 with brake pedal released so pin on brakelight switch is pushed in. Check that continuity exists between terminals No. 1 and 2 with brake pedal depressed so pin on brakelight switch is extended. Adjust or replace brakelight switch if operation is not as described. See «BRAKELIGHT SWITCH»(ref-151983-S37773445542003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
3. On models with cruise control, using ohmmeter, check that no continuity exists between terminals No. 1 and 2 with brake pedal released so pin on brakelight switch is pushed in. Check that continuity exists between terminals No. 1 and 2 with brake pedal depressed so pin on brakelight switch is extended.
4. Check that no continuity exists between terminals No. 3 and 4 with brake pedal depressed so pin on brakelight switch is extended. Check that continuity exists between terminals No. 3 and 4 with brake pedal released so pin on brakelight switch is pushed in. Adjust or replace brakelight switch if operation is not as described. See «BRAKELIGHT SWITCH»(ref-151983-S37773445542003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.

Scheme 572

1. Disconnect electrical connector at brakelight switch. Brakelight switch is located near top of brake pedal. Note terminal identification on brakelight switch. (Scheme 573)
2. Using ohmmeter, check that continuity exists between terminals No. 1 and 2 with brake pedal depressed so pin on brakelight switch is extended. Check that no continuity exists between terminals No. 1 and 2 with brake pedal released so pin on brakelight switch is pushed in. Adjust or replace brakelight switch if operation is not as described. See «BRAKELIGHT SWITCH»(ref-151983-S37773445542003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.

Scheme 573

CAMSHAFT POSITION SENSOR

For testing camshaft position sensor, see CAMSHAFT POSITION SENSOR under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article.

CRANKSHAFT POSITION SENSOR

For testing crankshaft position sensor, see CRANKSHAFT POSITION SENSOR under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article.

1. EGR gas temperature sensor is located near EGR valve. Remove EGR gas temperature sensor. See «EGR GAS TEMPERATURE SENSOR»(ref-151983-S12733396232003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & 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-151978-S29035942612003010900000) table. Replace EGR gas temperature sensor if resistance is not within specification. Reinstall EGR gas temperature sensor.

EGR GAS TEMPERATURE SENSOR RESISTANCE

Camry, Camry Solara, Celica, Corolla & ECHO

1. Ensure ignition is off. Disconnect electrical connector from Engine Coolant Temperature (ECT) sensor. See «ENGINE COOLANT TEMPERATURE SENSOR LOCATION (CAMRY, CAMRY SOLARA, CELICA, COROLLA & ECHO)»(ref-151978-S10987548812003091900000) table. Remove ECT sensor from vehicle. See «ENGINE COOLANT TEMPERATURE SENSOR»(ref-151983-S24989499072003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
2. Place probe end of ECT sensor and thermometer in container of water. Attach ohmmeter between electrical terminals No. 1 and 2 on ECT sensor. (Scheme 574)and (Scheme 575). Heat water and note that resistance is within specification in relation to temperature. (Scheme 576) Replace ECT sensor if resistance is not within specification.

ENGINE COOLANT TEMPERATURE SENSOR LOCATION (CAMRY, CAMRY SOLARA, CELICA, COROLLA & ECHO)

Scheme 574

Scheme 575

Scheme 576

Highlander, MR2, Matrix, Prius, RAV4 & Tacoma

1. Ensure ignition is off. Disconnect electrical connector from Engine Coolant Temperature (ECT) sensor. See «ENGINE COOLANT TEMPERATURE SENSOR LOCATION (HIGHLANDER, MR2, MATRIX, PRIUS, RAV4 & TACOMA)»(ref-151978-S18318470382003010900000) table. Remove ECT sensor. See «ENGINE COOLANT TEMPERATURE SENSOR»(ref-151983-S24989499072003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & 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 576) Replace ECT sensor if resistance is not within specification. ENGINE COOLANT TEMPERATURE SENSOR LOCATION (HIGHLANDER, MR2, MATRIX, PRIUS, RAV4 & TACOMA) Model Location Highlander On Flywheel End Of Cylinder Head & Contains Dark Gray 2-Pin Electrical Connector With White/Blue & White Wires MR2 On Flywheel End Of Cylinder Head & Contains Dark Gray 2-Pin Electrical Connector With Red/Blue & Brown Wires Matrix On Flywheel End Of Cylinder Head & Contains 2-Pin Electrical Connector With White & Brown Wires Prius On Flywheel End Of Cylinder Head & Contains Dark Gray 2-Pin Electrical Connector With White & Brown Wires RAV4 On Flywheel End Of Cylinder Head & Contains Dark Gray 2-Pin Electrical Connector With White & Brown Wires Tacoma On Coolant Housing At Rear Of Cylinder Head & Contains Dark Gray 2-Pin Electrical Connector With Green/Red & Blue/Black Wires

Scheme 577

1. A heated A/F sensor is mounted on exhaust manifold above catalytic converter. For testing of A/F sensor, see «AIR/FUEL SENSOR»(ref-151978-S01334015702003010900000). Another heated oxygen sensor is mounted on exhaust pipe after catalytic converter. This heated oxygen sensor is referred to as bank No. 1 sensor No. 2.
2. To test heater resistance on heated oxygen sensor, disconnect electrical connector for heated oxygen sensor. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 577) Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C). See «HEATED OXYGEN SENSOR»(ref-151983-S21698056612003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
3. To check that heater is not shorted, using ohmmeter, check that no continuity exists between E1 and HT terminals on electrical connector. (Scheme 577) Replace heated oxygen sensor if continuity exists. See «HEATED OXYGEN SENSOR»(ref-151983-S21698056612003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
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 TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 578

1. A heated A/F sensor is mounted on exhaust manifold above catalytic converter. For testing of A/F sensor, see «AIR/FUEL SENSOR»(ref-151978-S01334015702003010900000). Another heated oxygen sensor is mounted on exhaust pipe after catalytic converter. This heated oxygen sensor is referred to as bank No. 1 sensor No. 2.
2. To test heater resistance on heated oxygen sensor, disconnect electrical connector for heated oxygen sensor. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 578) Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C). See «HEATED OXYGEN SENSOR»(ref-151983-S21698056612003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
3. 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 TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 579

Scheme 580

1. Two heated oxygen sensors are used. One heated oxygen sensor is mounted on exhaust pipe in front of front catalytic converter. This heated 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 heated oxygen sensor is referred to as bank No. 1 sensor No. 2, or rear oxygen sensor.
2. To test heater resistance on heated oxygen sensor, disconnect electrical connector for appropriate heated oxygen sensor. Electrical connector for bank No. 1 sensor No. 1 is a 4-pin electrical connector located near front of center console. (Scheme 579) Electrical connector for bank No. 1 sensor No. 2 is a Gray 4-pin electrical connector located below passenger's side front seat and carpet, near center console. (Scheme 580)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 579)and (Scheme 580). Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C). See «HEATED OXYGEN SENSOR»(ref-151983-S21698056612003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
4. If problem exists with either heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

1. A heated oxygen sensor is mounted on exhaust pipe in front of catalytic converter. This heated 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 heated oxygen sensor is referred to as bank No. 1 sensor No. 2, or rear oxygen sensor.
2. To test heater resistance on heated oxygen sensor, disconnect electrical connector for appropriate heated oxygen sensor. Electrical connector for bank No. 1 sensor No. 1 is a Dark Gray 4-pin electrical connector located near exhaust manifold. (Scheme 581) 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 582)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 581)and (Scheme 582). Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C) and 23-32 ohms at 1472°F (800°C). See «HEATED OXYGEN SENSOR»(ref-151983-S21698056612003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
4. If problem exists with either heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 581

Scheme 582

1. A heated oxygen sensor is mounted on exhaust pipe in front of catalytic converter. This heated 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 heated oxygen sensor is referred to as bank No. 1 sensor No. 2, or rear oxygen sensor.
2. To test heater resistance on heated oxygen sensor, disconnect electrical connector for appropriate heated oxygen sensor. Electrical connector for bank No. 1 sensor No. 1 is a Gray 4-pin electrical connector located near exhaust pipe. (Scheme 583) Electrical connector for bank No. 1 sensor No. 2 is a Gray 4-pin electrical connector located below passenger's side front seat and carpet, near center console. (Scheme 584)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 583)and (Scheme 584). Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C). See «HEATED OXYGEN SENSOR»(ref-151983-S21698056612003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
4. If problem exists with either heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 583

Scheme 584

Scheme 585

1. Two heated Air/Fuel (A/F) sensors are used. Heated A/F sensors are mounted on exhaust manifold above catalytic converter. For testing of A/F sensors, see «AIR/FUEL SENSOR»(ref-151978-S01334015702003010900000). Two heated oxygen sensors are also used. Heated oxygen sensors are mounted on exhaust manifold below catalytic converters. Heated oxygen sensor for cylinders No. 1 and 4 is referred to as bank No. 1 sensor No. 2. Heated oxygen sensor for cylinders No. 2 and 3 is referred to as bank No. 2 sensor No. 2.
2. To test heater resistance on heated oxygen sensor, disconnect electrical connector for heated oxygen sensor. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 585) Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C). See «HEATED OXYGEN SENSOR»(ref-151983-S21698056612003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
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 TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

1. Three heated oxygen sensors are used with 2 being mounted on exhaust manifold, above catalytic converters, and one on exhaust pipe behind catalytic converters. Heated oxygen sensor for cylinders No. 1 and 4 is referred to as bank No. 1 sensor No. 1. Heated oxygen sensor for cylinders No. 2 and 3 is referred to as bank No. 2 sensor No. 1. Heated oxygen sensor mounted on exhaust pipe is referred to as bank No. 1 sensor No. 2.
2. To test heater resistance on heated oxygen sensor, disconnect electrical connector for appropriate heated oxygen sensor. (Scheme 586)- (Scheme 588). Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 586)- (Scheme 588). Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C) and 23-32 ohms at 1472°F (800°C). See «HEATED OXYGEN SENSOR»(ref-151983-S21698056612003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
3. If problem exists with any heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 586

Scheme 587

Scheme 588

1. A heated oxygen sensor is mounted on exhaust pipe in front of catalytic converter. This heated 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 heated oxygen sensor is referred to as bank No. 1 sensor No. 2, or rear oxygen sensor.
2. To test heater resistance on heated oxygen sensor, disconnect electrical connector for appropriate heated oxygen sensor. Electrical connector for bank No. 1 sensor No. 1 is a Dark Gray 4-pin electrical connector located near exhaust manifold. (Scheme 589) Electrical connector for bank No. 1 sensor No. 2 is a Dark Gray 4-pin electrical connector located below passenger's side carpet, near center console. (Scheme 590)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 589)and (Scheme 590). Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C). See «HEATED OXYGEN SENSOR»(ref-151983-S21698056612003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
4. If problem exists with either heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 589

Scheme 590

Scheme 591

Scheme 592

1. Two heated Air/Fuel (A/F) sensors are used. Heated A/F sensors are mounted on exhaust manifold above catalytic converter. For testing of A/F sensors, see «AIR/FUEL SENSOR»(ref-151978-S01334015702003010900000). Two heated oxygen sensors are also used. Heated oxygen sensors are mounted on exhaust manifold below catalytic converters. Heated oxygen sensor for cylinders No. 1 and 4 is referred to as bank No. 1 sensor No. 2. Heated oxygen sensor for cylinders No. 2 and 3 is referred to as bank No. 2 sensor No. 2.
2. To test heater resistance on heated oxygen sensor, disconnect electrical connector for heated oxygen sensor. (Scheme 591)and (Scheme 592). Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 591)and (Scheme 592). Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C) and 23-32 ohms at 1472°F (800°C). See «HEATED OXYGEN SENSOR»(ref-151983-S21698056612003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
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 TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 593

1. A heated Air/Fuel (A/F) sensor is mounted on exhaust pipe in front of catalytic converter. For testing of A/F sensor, see «AIR/FUEL SENSOR»(ref-151978-S01334015702003010900000). A 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 heated oxygen sensor, disconnect electrical connector for heated oxygen sensor. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 593) Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C) and 23-32 ohms at 1472°F (800°C). See «HEATED OXYGEN SENSOR»(ref-151983-S21698056612003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
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 TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 594

Scheme 595

Scheme 596

Scheme 597

1. Disconnect electrical connector from ignition switch on bottom of upper steering column bracket. (Scheme 594) Note ignition switch electrical terminals and ignition lock cylinder positions. (Scheme 595)- (Scheme 597).
2. Using ohmmeter, check that continuity is as specified between indicated ignition switch electrical terminals in relation to ignition lock cylinder position. See «IGNITION SWITCH CONTINUITY»(ref-151978-S30634627162003010900000) table. Replace ignition switch if defective. See «IGNITION SWITCH»(ref-151983-S22571045782003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article. IGNITION SWITCH CONTINUITY Application Ign. Lock Cylinder Position Ign. Switch Terminals Specification Camry, Camry Solara & Prius & Tacoma LOCK (1) (1) ACC 2 & 3 Continuity ON 2, 3 & 4; 6 & 7 Continuity START 1, 2 & 4; 6, 7 & 8 Continuity Celica, Corolla, ECHO, Highlander, MR2 & RAV4 LOCK (1) (1) ACC 1 & 3 Continuity ON 1, 2 & 3; 5 & 6 Continuity START 1 & 2; 4, 5 & 6 Continuity (1) There should be no continuity between any terminals.

INTAKE AIR TEMPERATURE SENSOR

Intake air temperature sensor is incorporated with airflow meter. See AIRFLOW METER .

KNOCK SENSOR

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

Camry (PZEV), Celica, Corolla & Matrix

Note. Camry equipped with Partial Zero Emissions Vehicle (PZEV) option use a 2 terminal knock sensor.

1. Knock sensor is located on side of cylinder block. Manufacturer recommends removing knock sensor from cylinder block before testing. See «KNOCK SENSOR»(ref-151983-S01735660332003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.
2. Using an ohmmeter, measure the resistance between the knock sensor terminals. Resistance should be 120-280 k/ohms at 68°F (20°C). (Scheme 598) If the resistance is not as specified, replace the knock sensor. See «KNOCK SENSOR»(ref-151983-S01735660332003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.

Scheme 598

Camry, Camry Solara, ECHO, Highlander, MR2, Prius, RAV4 & Tacoma

1. Knock sensor is located on side of cylinder block. Manufacturer recommends removing knock sensor from cylinder block before testing. See «KNOCK SENSOR»(ref-151983-S01735660332003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & 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.

Camry, Camry Solara, Celica, Corolla, ECHO, Highlander, RAV4 & Tacoma

Note. Park/Neutral Position (PNP) switch is used only on A/T models.

1. Disconnect electrical connector from Park/Neutral Position (PNP) switch. PNP switch is mounted on side of transmission/transaxle. Note terminal identification. (Scheme 599)- (Scheme 601).
2. Using ohmmeter, check for continuity between specified terminals with shift lever in proper positions. See «PARK/NEUTRAL POSITION SWITCH SPECIFICATIONS»(ref-151978-S14605473032003010900000) table.
3. If proper continuity does not exist, adjust or replace PNP switch as necessary. For adjustment or replacement of PNP switch, see «PARK/NEUTRAL POSITION SWITCH»(ref-151983-S32348664282003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.

PARK/NEUTRAL POSITION SWITCH SPECIFICATIONS

Scheme 599

Scheme 600

Scheme 601

Scheme 602

1. Remove Positive Temperature Coefficient (PTC) heater along with heater core. See appropriate HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
2. To test PTC heater for continuity, using ohmmeter, check that continuity exists between each electrical terminal and ground terminal on PTC heater. (Scheme 602) Replace PTC heater if continuity does not exist between any electrical terminal and ground terminal.
3. To test PTC heater resistance, remove PTC heater from heater core. Place probe end of PTC heater and thermometer in container of water. Attach ohmmeter between electrical terminals on PTC heater.
4. Heat water and note that resistance is within specification in relation to temperature. See «PTC HEATER RESISTANCE»(ref-151978-S03298195482003010900000) table. Replace PTC heater if resistance is not within specification. PTC HEATER RESISTANCE Temperature Ohms 77°F (25°C) 4800-5200 104°F (40°C) 2550-2850 212°F (100°C) 260-340

For PTC heater inspection procedures (Scheme 603)

Scheme 603

POWER STEERING PRESSURE SENSOR

Note. Power steering pressure sensor may also be referred to as power steering oil pressure sensor.

For power steering pressure sensor inspection procedures (Scheme 604) If problem exists with power steering pressure sensor, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 604

POWER STEERING PRESSURE SWITCH

Note. Power steering pressure switch may also be referred to as power steering oil pressure switch.

Camry, Camry Solara, Celica, Corolla, RAV4 & Tacoma

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

For power steering pressure sensor inspection procedures (Scheme 605)

Scheme 605

For testing of throttle position sensor (Scheme 606)- (Scheme 608). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 606

Scheme 607

Scheme 608

For testing of throttle position sensor (Scheme 609)- (Scheme 611). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 609

Scheme 610

Scheme 611

Celica (VIN "R")

For testing of throttle position sensor (Scheme 612)- (Scheme 615). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 612

Scheme 613

Scheme 614

Scheme 615

Celica (VIN "Y")

For testing of throttle position sensor (Scheme 616)- (Scheme 622). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 616

Scheme 617

Scheme 618

Scheme 619

Scheme 620

Scheme 621

Scheme 622

For testing of throttle position sensor (Scheme 623)- (Scheme 627). To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 623

Scheme 624

Scheme 625

Scheme 626

Scheme 627

For testing of throttle position sensor (Scheme 628)- (Scheme 632). To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 628

Scheme 629

Scheme 630

Scheme 631

Scheme 632

For testing of throttle position sensor (Scheme 633)- (Scheme 637). To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 633

Scheme 634

Scheme 635

Scheme 636

Scheme 637

MR2 (With M/T)

For testing of throttle position sensor (Scheme 638)- (Scheme 641). To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 638

Scheme 639

Scheme 640

Scheme 641

MR2 (With SMT)

For testing of throttle position sensor (Scheme 642)- (Scheme 646). To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 642

Scheme 643

Scheme 644

Scheme 645

Scheme 646

For testing of throttle position sensor (Scheme 647)- (Scheme 651). To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 647

Scheme 648

Scheme 649

Scheme 650

Scheme 651

For testing of throttle position sensor (Scheme 652)- (Scheme 657). To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 652

Scheme 653

Scheme 654

Scheme 655

Scheme 656

Scheme 657

For testing of throttle position sensor (Scheme 658)- (Scheme 661). To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 658

Scheme 659

Scheme 660

Scheme 661

For testing of throttle position sensor (Scheme 662)- (Scheme 665). To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 662

Scheme 663

Scheme 664

Scheme 665

VACUUM SENSOR FOR HYDROCARBON ABSORBER CATALYST SYSTEM

Note. Hydrocarbon absorber catalyst system is also referred to as HCAC system.

For testing procedures of vacuum sensor for hydrocarbon absorber catalyst system (Scheme 666)- (Scheme 669). To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 666

Scheme 667

Scheme 668

Scheme 669

VAPOR PRESSURE SENSOR

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

VARIABLE VALVE TIMING SENSOR

Note. Variable Valve Timing (VVT) sensor may also be referred to as camshaft position sensor.

All Models

For Variable Valve Timing (VVT) sensor testing, see CAMSHAFT POSITION SENSOR under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article.

For testing procedures of Vehicle Speed Sensor (VSS) (Scheme 670)- (Scheme 672).

Scheme 670

Scheme 671

Scheme 672

For testing procedures of Vehicle Speed Sensor (VSS) (Scheme 673)

Scheme 673

For testing procedures of Vehicle Speed Sensor (VSS) (Scheme 674)

Scheme 674

For testing procedures of Vehicle Speed Sensor (VSS) (Scheme 675)- (Scheme 677).

Scheme 675

Scheme 676

Scheme 677

For testing procedures of Vehicle Speed Sensor (VSS) (Scheme 678)

Scheme 678

1. Wheel speed sensors on each wheel deliver an input signal to skid control Electronic Control Unit (ECU). Skid control ECU converts input signals from wheel speed sensors to a 4-pulse input signal to the instrument cluster.
2. Instrument cluster then converts 4-pulse input signal to a rectangular waveform and then sends vehicle speed signal to Engine Control Module (ECM).
3. If problem exists with vehicle speed signal, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

1. Wheel speed sensors on each wheel deliver an input signal to Anti-Lock Brake System (ABS) Electronic Control Unit (ECU). ABS ECU converts input signals from wheel speed sensors to a 4-pulse input signal to the instrument cluster.
2. Instrument cluster then converts 4-pulse input signal to a rectangular waveform and then sends vehicle speed signal to Engine Control Module (ECM).
3. If problem exists with vehicle speed signal, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

For testing procedures of Vehicle Speed Sensor (VSS) (Scheme 679)- (Scheme 681).

Scheme 679

Scheme 680

Scheme 681

1. Wheel speed sensors on each wheel deliver an input signal to brake Electronic Control Unit (ECU) for the Anti-Lock Brake System (ABS).
2. Brake ECU converts input signals from wheel speed sensors to a 4-pulse input signal to the instrument cluster. Instrument cluster then converts 4-pulse input signal to a rectangular waveform and then sends vehicle speed signal to Engine Control Module (ECM).
3. If problem exists with vehicle speed signal, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Vehicle Speed Sensor (VSS) is mounted on transaxle. Testing information for the VSS is not available from manufacturer. If problem exists with vehicle speed sensor, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

For testing Vehicle Speed Sensor (VSS) (Scheme 682)

Scheme 682

THROTTLE CONTROL MOTOR

Note. On MR2, there are 2 types of manual transaxles used. Sequential manual transaxle may be identified by shift lever pattern which consists of "R", "N", "S" and "+" in place of the conventional type shift lever pattern and there is no clutch pedal.

Camry, Camry Solara, MR2 With Sequential Manual Transaxle & Prius

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

A/C COMPRESSOR CLUTCH RELAY

Note. A/C compressor clutch relay may also be referred to as A/C compressor relay or magnetic clutch relay.

For A/C compressor clutch relay testing procedure (Scheme 683)

Scheme 683

For A/C compressor clutch relay testing procedure (Scheme 684)

Scheme 684

For A/C compressor clutch relay testing procedure (Scheme 685)

Scheme 685

Corolla, ECHO, Highlander, Matrix, Prius, RAV4 & Tacoma

Note. Manufacturer does not supply A/C compressor clutch relay testing procedures for RAV4 and Tacoma.

For A/C compressor clutch relay testing procedure (Scheme 686)

Scheme 686

Scheme 687

1. Remove A/C compressor clutch relay from relay box on firewall at driver's side front corner of engine compartment. (Scheme 696)
2. To test A/C compressor clutch relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on A/C compressor clutch relay. (Scheme 687)
3. To test A/C compressor clutch relay operation, apply battery voltage and ground to A/C compressor clutch relay. Using ohmmeter, check for continuity between specified terminals on A/C compressor clutch relay. (Scheme 687) Replace A/C compressor clutch relay if defective.

A/F HEATER RELAY

Note. A/F heater relay may also be referred to as A/F HTR relay, A/F sensor relay or A/F relay.

Camry, Camry Solara & Tacoma

Note. Camry, Camry Solara and Tacoma use the EFI relay to power the A/F heater. For diagnostic procedure, see EFI MAIN RELAY .

Scheme 688

1. Remove A/F heater relay from fuse/relay box at driver's side front corner of engine compartment, just in front of strut tower. To test A/F heater relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on A/F heater relay. (Scheme 688)
2. To test A/F heater relay operation, apply battery voltage and ground to A/F heater relay. Using ohmmeter, check for continuity between specified terminals on A/F heater relay. (Scheme 688) Replace A/F heater relay if defective.

For A/F heater relay testing procedure (Scheme 689)

Scheme 689

CIRCUIT OPENING RELAY

1. Ensure ignition is off. Remove circuit opening relay. See «CIRCUIT OPENING RELAY LOCATION»(ref-151978-S40476220872003010900000) table and (Scheme 690) - (Scheme 699).
2. To test circuit opening relay, using ohmmeter, check for continuity or open between specified terminals on circuit opening relay. see scheme 389and see scheme 390.
3. To test circuit opening relay operation, apply battery voltage and ground to circuit opening relay. Using ohmmeter, check for continuity between specified terminals on circuit opening relay. see scheme 389and see scheme 390. Replace circuit opening relay if defective.

CIRCUIT OPENING RELAY LOCATION (1)

Scheme 690

Scheme 691

Scheme 692

Scheme 693

Scheme 694

Scheme 695

Scheme 696

Scheme 697

Scheme 698

Scheme 699

EFI MAIN RELAY

Note. On Corolla, EFI main relay may also be referred to as EFI relay or F-HTR relay. On all other models, 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-151978-S07626661532003010900000) table.
2. To test EFI main relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on EFI main relay. see scheme 389and see scheme 390.
3. To test EFI main relay operation, apply battery voltage and ground to EFI main relay. Using ohmmeter, check for continuity between specified terminals on EFI main relay. see scheme 389and see scheme 390. Replace EFI main relay if defective. EFI MAIN RELAY LOCATION Application Location Camry & Camry Solara In Fuse/Relay Box At Driver's Side Front Corner Of Engine Compartment Celica, Corolla, ECHO, Highlander & Matrix In Fuse/Relay Box At Driver's Side Front Corner Of Engine Compartment, Just In Front Of Strut Tower MR2 In Relay Box On Firewall At Driver's Side Front Corner Of Engine Compartment Prius, RAV4 & Tacoma In Fuse/Relay Box At Driver's Side Front Corner Of Engine Compartment

HTR SUB1 RELAY

Note. HTR SUB1 relay may also be referred to as heater sub relay or heater relay.

Scheme 700

1. Remove HTR SUB1 relay from fuse/relay box located at driver's side front corner of engine compartment, just in front of strut tower. (Scheme 700)
2. Note terminals on HTR SUB1 relay. (Scheme 700) To test HTR SUB1 relay continuity, using ohmmeter, check that continuity exists between terminals No. 1 and 2 on HTR SUB1 relay and that no continuity exists between terminals No. 3 and 5 on HTR SUB1 relay. If continuity and no continuity are as specified, go to next step. If continuity and no continuity are not as specified, replace HTR SUB1 relay.
3. To test HTR SUB1 relay operation, apply battery voltage and ground to terminals No. 1 and 2 on HTR SUB1 relay. Using ohmmeter, check that continuity exists between terminals No. 3 and 5 on HTR SUB1 relay. Replace HTR SUB1 relay if continuity does not exist between terminals No. 3 and 5.

IG2 RELAY

Note. IG2 relay may also be referred to as ignition relay.

IG2 relay is located in fuse/relay box at driver's side front corner of engine compartment, just in front of strut tower. Testing information is not available from manufacturer. Consult wiring diagram for IG2 relay testing. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

1. Remove IG2 relay from relay box on firewall at driver's side front corner of engine compartment. (Scheme 696)
2. To test IG2 relay continuity, using ohmmeter, check for continuity and open between specified terminals on IG2 relay. see scheme 392
3. To test IG2 relay operation, apply battery voltage and ground to IG2 relay. Using ohmmeter, check for continuity between specified terminals on IG2 relay. see scheme 392 Replace IG2 relay if defective.

IG2 relay is located in fuse/relay box at driver's side front corner of engine compartment. Testing information is not available from manufacturer. Consult wiring diagram for IG2 relay testing. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

1. Remove IG2 relay from relay box located at driver's side front corner of engine compartment. (Scheme 698)
2. To test IG2 relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on IG2 relay. see scheme 392
3. To test IG2 relay operation, apply battery voltage and ground to IG2 relay. Using ohmmeter, check for continuity between specified terminals on IG2 relay. see scheme 392 Replace IG2 relay if defective.

FUEL SYSTEM PRESSURE RELEASE

For fuel system pressure release procedures, see FUEL SYSTEM PRESSURE RELEASE under FUEL SYSTEMS in REMOVAL & INSTALLATION - 4-CYLINDER article.

FUEL DELIVERY

Note. For fuel system pressure testing, see FUEL PRESSURE under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article.

See CIRCUIT OPENING RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS.

See EFI MAIN RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS.

Fuel Injectors (Camry Except PZEV)

For fuel injector testing procedures on models not equipped with Partial Zero Emission Vehicles (PZEV) option (Scheme 702)- (Scheme 703).

Scheme 701

Scheme 702

Fuel Injectors (Camry PZEV)

For fuel injector testing procedures on Camry equipped with Partial Zero Emission Vehicles (PZEV) option (Scheme 704)- (Scheme 705).

Scheme 703

Scheme 704

Fuel Injectors (Camry Solara)

For fuel injector testing procedures (Scheme 706)- (Scheme 707).

Scheme 705

Scheme 706

Fuel Injectors (Celica)

For fuel injector testing procedures (Scheme 708)- (Scheme 709).

Scheme 707

Scheme 708

Fuel Injectors (Corolla)

For fuel injector testing procedures (Scheme 710)- (Scheme 711).

Scheme 709

Scheme 710

Fuel Injectors (ECHO)

For fuel injector testing procedures (Scheme 712)- (Scheme 713).

Scheme 711

Scheme 712

Fuel Injectors (Highlander)

For fuel injector testing procedures (Scheme 714)- (Scheme 715).

Scheme 713

Scheme 714

Fuel Injectors (Matrix)

For fuel injector testing procedures (Scheme 716)- (Scheme 717).

Scheme 715

Scheme 716

Fuel Injectors (MR2)

For fuel injector testing procedures (Scheme 718)- (Scheme 720).

Scheme 717

Scheme 718

Scheme 719

Fuel Injectors (Prius)

For fuel injector testing procedures (Scheme 721)- (Scheme 722).

Scheme 720

Scheme 721

Fuel Injectors (RAV4)

For fuel injector testing procedures (Scheme 723)- (Scheme 725).

Scheme 722

Scheme 723

Scheme 724

Fuel Injectors (Tacoma)

For fuel injector testing procedures (Scheme 726)- (Scheme 727).

Scheme 725

Scheme 726

Fuel Cut System (Camry, Corolla, Highlander & Matrix)

1. Connect Toyota hand-held tester or scan tool to data link connector No. 3 located at driver's side of instrument panel. (Scheme 498)and (Scheme 523). Hand-held tester or scan tool is used to read engine RPM. Start engine and warm to normal operating temperature.
2. Gradually increase engine speed to 3500 RPM. Using stethoscope, check for fuel injector operating sound. Ensure when throttle lever is released, fuel injector stops operating momentarily and then resumes operating. Shut engine off. Remove hand-held tester or scan tool.

Fuel Cut System (Camry Solara, Celica, ECHO, MR2, RAV4 & Tacoma)

1. Connect Toyota hand-held tester or scan tool to data link connector No. 3 located at driver's side of instrument panel. (Scheme 503)- (Scheme 541). Hand-held tester or scan tool is used to read engine RPM. Start engine and warm engine to normal operating temperature.
2. Ensure A/C is off. Gradually increase engine speed to 3500 RPM. 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).
3. Ensure fuel return RPM is within specification. See «FUEL CUT SYSTEM SPECIFICATIONS»(ref-151978-S18458059582003010900000) table. Shut engine off. Remove hand-held tester or scan tool.

FUEL CUT SYSTEM SPECIFICATIONS (1)

Fuel Cut System (Prius)

Scheme 727

1. It is necessary to put transit in inspection mode so engine will run continuously when checking fuel cut system. To put transit in inspection mode, perform the following steps within 60 seconds: Ensure ignition is off and then turn ignition on. Ensure transaxle is in Park and then fully depress accelerator pedal 2 times. Place transaxle in Neutral and then fully depress accelerator pedal 2 times. Place transaxle back in Park and then fully depress accelerator pedal 2 times.
2. Check that master warning light on instrument cluster at center of instrument panel is flashing to indicate inspection mode operation. (Scheme 728) Master warning light may also be referred to as hybrid system error warning light. Turn ignition switch to START position to start engine. Engine will now start and run continuously.
3. Connect Toyota hand-held tester or scan tool to data link connector No. 3 located at driver's side of instrument panel. (Scheme 531) Hand-held tester or scan tool is used to read engine RPM. Warm engine to normal operating temperature.
4. Ensure A/C is off. Gradually increase engine speed to 2250 RPM. Using stethoscope, check for fuel injector operating sound. Ensure when throttle lever is released, fuel injector stops operating momentarily and then resumes operating. Ensure when throttle lever is released, fuel injector stops operating momentarily and then resumes operating at 1400 RPM which is the fuel return RPM. Shut engine off. Remove hand-held tester or scan tool.

FUEL TANK CAP

For fuel tank cap testing, see appropriate FUEL EVAPORATIVE SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS .

For Idle Air Control (IAC) system testing procedures (Scheme 729)- (Scheme 731). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

Scheme 728

Scheme 729

Scheme 730

For Idle Air Control (IAC) system testing procedures (Scheme 732)- (Scheme 733).

Scheme 731

Scheme 732

Celica & ECHO

For Idle Air Control (IAC) system testing procedures (Scheme 734)- (Scheme 735).

Scheme 733

Scheme 734

Note. Idle Air Control (IAC) valve is also referred to as Idle Speed Control (ISC) valve.

For Idle Air Control (IAC) system testing procedures (Scheme 736)

Scheme 735

Scheme 736

1. If problem exists in Idle Air Control (IAC) valve or wiring circuit, a Diagnostic Trouble Code (DTC) P0505 may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.
2. To test IAC valve operation, remove IAC valve from throttle body. See «THROTTLE BODY»(ref-151983-S27294477362003010900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - 4-CYLINDER article. Reinstall electrical connector on IAC valve.
3. Turn ignition on. Check that valve on inside of IAC valve moves from half open to fully closed, fully open and then returns to half open within.5 second. (Scheme 737) Turn ignition off. If IAC valve operates as specified, wiring circuit, Engine Control Module (ECM) and IAC valve are okay.
4. If IAC valve operates as specified, wiring circuit, Engine Control Module (ECM) and IAC valve are okay. Clear any stored DTCs from ECM after checking IAC valve operation. See CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article. If IAC valve does not operate, check wiring circuit between ECM and IAC valve. ECM is located behind glove box. For illustration of ECM location (Scheme 334) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If wiring circuit and ECM are okay, replace IAC valve.

MR2 With Standard Type Manual Transaxle

Note. Idle Air Control (IAC) valve is used only on models with standard type manual transaxle.

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See «IDLE SPEED & MIXTURE»(ref-151948-S09844152842003010900000) in ON-VEHICLE ADJUSTMENTS - 4-CYLINDER article.
2. Turn ignition off. Apply parking brake and place transaxle in Neutral. Ensure A/C is off. Install Jumper Wire (SST 09843-18020 or SST 09843-18040) between terminals No. 4 (CG) and No. 13 (TC) on data link connector No. 3. (Scheme 738) Data link connector No. 3 is located behind driver's side of instrument panel. (Scheme 527)
3. Start engine and note engine speed. Engine speed should increase to 1000-1500 RPM for 5 seconds and then return to idle speed. If engine speed is as specified, turn ignition off and remove jumper wire. If engine speed is not as specified, turn ignition off, remove jumper wire and go to next step.
4. To test IAC operation, remove IAC valve from throttle body. See «THROTTLE BODY»(ref-151983-S27294477362003010900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - 4-CYLINDER article. Check that valve on inside of IAC valve is half open. (Scheme 739) Reinstall electrical connector on IAC valve.
5. Turn ignition on. Check that valve on inside of IAC valve moves from half open to fully closed, fully open and then returns to half open within.5 second. (Scheme 739) Turn ignition off.
6. If IAC valve operates as specified, 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. ECM is located on inside of firewall, directly behind driver's seat and luggage compartment. For illustration of ECM location (Scheme 335) See «ENGINE CONTROL MODULE»(ref-151983-S05011669822003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION - 4-CYLINDER article for removal of components for access to ECM. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If wiring circuit and ECM are okay, replace IAC valve.

Scheme 737

Scheme 738

The idle speed is controlled by the Electric Throttle Control System (ETCS). The ETCS is composed of the throttle motor to operate the throttle valve, the magnetic clutch to connect the throttle motor with the throttle valve, the Throttle Position (TP) sensor to detect the opening angle of the throttle valve, the accelerator pedal position sensor to detect the accelerator pedal position, the ECM to control the ETCS and the one valve type throttle body. The ECM controls the throttle motor to make the throttle valve opening angle properly for the target idle speed. For testing of these components, see THROTTLE BODY under IDLE CONTROL SYSTEMS.

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See «IDLE SPEED & MIXTURE»(ref-151948-S09844152842003010900000) in ON-VEHICLE ADJUSTMENTS - 4-CYLINDER article.
2. Turn ignition off. Apply parking brake and place transaxle in Neutral. Ensure A/C is off. Install Jumper Wire (SST 09843-18040) between terminals No. 4 (CG) and No. 13 (TC) on data link connector No. 3. (Scheme 738) Data link connector No. 3 is located behind driver's side of instrument panel. (Scheme 535)
3. Start engine and note engine speed. Engine speed should increase to 900-1500 RPM for 5 seconds and then return to idle speed. If engine speed is as specified, turn ignition off and remove jumper wire. If engine speed is not as specified, turn ignition off, remove jumper wire and go to next step.
4. To test Idle Air Control (IAC) valve operation, remove IAC valve from throttle body. See «THROTTLE BODY»(ref-151983-S27294477362003010900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - 4-CYLINDER article. Check that valve on inside of IAC valve is half open. (Scheme 737) Reinstall electrical connector on IAC valve.
5. Turn ignition on. Check that valve on inside of IAC valve moves from half open to fully closed, fully open and then returns to half open within.5 second. (Scheme 737) Turn ignition off.
6. If IAC valve operates as specified, 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. ECM is located behind passenger's side kick panel, just below instrument panel. For illustration of ECM location (Scheme 337) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If wiring circuit and ECM are okay, replace IAC valve.

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See «IDLE SPEED & MIXTURE»(ref-151948-S09844152842003010900000) in ON-VEHICLE ADJUSTMENTS - 4-CYLINDER article.
2. Turn ignition off. Apply parking brake and place transmission in Neutral. Install Jumper Wire (SST 09843-18020 or SST 09843-18040) between terminals No. 4 (CG) and No. 13 (TC) on data link connector No. 3. (Scheme 738) Data link connector No. 3 is located behind driver's side of instrument panel. (Scheme 541)
3. Start engine and note engine speed. Engine speed should increase to 1000-1500 RPM for 5 seconds and then return to idle speed. If engine speed is as specified, turn ignition off and remove jumper wire. If engine speed is not as specified, turn ignition off, remove jumper wire and go to next step.
4. To test Idle Air Control (IAC) valve operation, remove IAC valve from throttle body. See «THROTTLE BODY»(ref-151983-S27294477362003010900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - 4-CYLINDER article. Check that valve on inside of IAC valve is half open. (Scheme 740) Reinstall electrical connector on IAC valve.
5. Disconnect electrical connector from Engine Coolant Temperature (ECT) sensor. ECT sensor is located on coolant housing at rear of cylinder head and contains Dark Gray 2-pin electrical connector with Green/Red and Blue/Black 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 740)
7. Turn ignition off. Reinstall electrical connector on ECT sensor. If IAC valve operates as specified, 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 ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. ECM is located behind glove box. For illustration of ECM location (Scheme 338) If wiring circuit and ECM are okay, replace IAC valve.

Scheme 739

Scheme 740

Scheme 741

1. Electronic Throttle Control System (ETCS) is used for controlling idle speed. ETCS consists of throttle body, accelerator pedal position sensor, Throttle Position (TP) sensor, throttle control motor and Engine Control Module (ECM).
2. To test throttle control motor operation, turn ignition on. Depress accelerator pedal to operate accelerator pedal position sensor while listening for operating sound at throttle control motor and ensure that no grinding noise is heard at throttle control motor and throttle body.
3. Accelerator pedal position sensor is located near top of accelerator pedal and throttle control motor is located on the throttle body. (Scheme 741)
4. If throttle control motor operating sound is heard, go to next step. If throttle control motor operating sound is not heard, throttle control motor, wiring harness or ECM may be defective. ECM is located on behind glove box. For illustration of ECM location, see «ENGINE CONTROL MODULE»(ref-151978-S08085117732003080600000) under COMPONENT LOCATIONS.
5. For wiring of throttle control motor, see ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. For testing of throttle control motor, go to step 10.
6. To test accelerator pedal position sensor, turn ignition off. Connect Toyota hand-held tester or scan tool to data link connector No. 3 located at driver's side of instrument panel. (Scheme 498)and (Scheme 503). Turn ignition on. Hand-held tester or scan tool is used to read throttle valve opening which is displayed as a percentage.
7. Ensure Malfunction Indicator Light (MIL) on instrument panel is not illuminated. MIL is displayed as an engine icon. If MIL is not illuminated, go to next step. If MIL is illuminated, a Diagnostic Trouble Code (DTC) may be stored in ECM. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.
8. Read throttle valve opening on hand-held tester or scan tool by accessing THROTTLE POS under CURRENT DATA. Read throttle valve opening while fully depressing accelerator pedal to operate accelerator pedal position sensor. Throttle valve opening should be 60 percent or more. Turn ignition off. If throttle valve opening is 60 percent or more, go to step 10. If throttle valve opening is not at least 60 percent, problem may exist in accelerator position sensor, wiring circuit or ECM.
9. If necessary to check wiring between ECM and accelerator pedal position sensor, see ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. ECM is located behind glove box. For illustration of ECM location, see «ENGINE CONTROL MODULE»(ref-151978-S08085117732003080600000) under COMPONENT LOCATIONS. For testing of accelerator pedal position sensor, see «ACCELERATOR PEDAL POSITION SENSOR»(ref-151978-S19135529812003010900000) under ENGINE SENSORS & SWITCHES.
10. To test throttle control motor, disconnect electrical connector from side of throttle body. (Scheme 741) Note electrical terminal identification on throttle body. (Scheme 742) Using ohmmeter, check resistance between specified terminals on throttle control motor. See «THROTTLE CONTROL MOTOR RESISTANCE»(ref-151978-S38875932482003010900000) table. If resistance is within specification, reinstall electrical connector. If resistance is not within specification, replace throttle body with throttle control motor as an assembly. THROTTLE CONTROL MOTOR RESISTANCE Terminal k-Ohms M+ & M-.3-100.0
11. To test Throttle Position (TP) sensor, disconnect electrical connector from side of throttle body. (Scheme 741) Note electrical terminal identification on throttle body. (Scheme 742) Using ohmmeter, check resistance between VC and E2 terminals on throttle body. Replace throttle body with TP sensor if resistance is not 1200-3200 ohms at 68°F (20°C). THROTTLE POSITION SENSOR RESISTANCE Terminal Ohms @ 68°F (20°C) VC & E2 1200-3200

Celica (With VIN "R")

Check that throttle linkage moves freely at throttle body. Procedure for checking vacuum supply at throttle body is not available from manufacturer.

Celica (With VIN "Y")

For throttle body inspection procedure (Scheme 743)- (Scheme 744).

Scheme 742

Scheme 743

For throttle body inspection procedure (Scheme 745)

Scheme 744

ECHO, MR2 With Standard Type Manual Transaxle & RAV4

Check that throttle linkage moves freely at throttle body. Procedure for checking vacuum supply at throttle body is not available from manufacturer. On RAV4, check that there is no clearance between the throttle stop screw and throttle lever when the throttle valve is fully closed.

Scheme 745

1. Check that throttle linkage moves freely at throttle body. Ensure no vacuum ports on throttle body are restricted. Procedure for checking vacuum supply at throttle body is not available from manufacturer.
2. Check that no clearance exists between throttle stop screw and throttle lever when throttle is fully closed. (Scheme 746) If clearance exists between throttle stop screw and throttle lever with throttle fully closed, go to next step.
3. Loosen lock nut on throttle stop screw. (Scheme 746) With clearance between throttle stop screw and throttle lever, hold throttle fully closed and tighten throttle stop screw until it just contacts throttle lever. Once throttle stop screw contacts the throttle lever, tighten throttle stop screw an additional 1/4 turn and then tighten lock nut. Ensure Throttle Position (TP) sensor operates properly after performing this procedure. See «THROTTLE POSITION SENSOR»(ref-151978-S05002081912003010900000) under ENGINE SENSORS & SWITCHES.

MR2 With Sequential Manual Transaxle

Note. A standard type manual transaxle and a sequential manual transaxle may be used. On models with a standard type Manual Transaxle (M/T), the driver operates the clutch and shifts the transaxle. On models with Sequential Manual Transaxle (SMT), the transaxle is electronically controlled and the clutch is operated and transaxle is shifted hydraulically by moving shift lever forward or backward. The SMT may be identified by shift lever pattern which consists of "R", "N", "S" and "+" in place of the conventional type shift lever pattern and there is no clutch pedal. On this model, Electronic Throttle Control System (ETCS) is used for controlling idle speed. ETCS consists of throttle body, accelerator pedal position sensor, Throttle Position (TP) sensor, throttle control motor, magnetic clutch and Engine Control Module (ECM).

1. Ensure throttle cable and throttle lever on throttle body move smoothly. Note location of throttle control motor on throttle body. (Scheme 747)
2. To check throttle control motor operation, turn ignition on. Rotate throttle lever on throttle body to full throttle while listing for operating sound at throttle control motor and note that no grinding noise is heard at throttle control motor and throttle body. Throttle lever will also rotate accelerator pedal position sensor.
3. If throttle control motor operating sound is heard, go to next step. If throttle control motor operating sound is not heard, throttle control motor, wiring harness or ECM may be defective. ECM is located on inside of firewall, directly behind driver's seat and luggage compartment. For illustration of ECM location (Scheme 325) To remove components for access to ECM, see «ENGINE CONTROL MODULE»(ref-151983-S05011669822003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION - 4-CYLINDER article. For testing of throttle control motor, go to step 12. For wiring of throttle control motor, see ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
4. To test operation of accelerator pedal position sensor, Toyota hand-held tester may be used or voltmeter may be used. If using hand-held tester, go to next step. If using voltmeter, go to step 8.
5. Connect hand-held tester to data link connector No. 3 located at driver's side of instrument panel. (Scheme 527) Hand-held tester is used to read throttle valve opening which is displayed as a percentage. Ensure Malfunction Indicator Light (MIL) on instrument panel is not illuminated. MIL is displayed as an engine icon. If MIL is not illuminated, go to next step. If MIL is illuminated, a Diagnostic Trouble Code (DTC) may be stored in ECM. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.
6. Rotate throttle lever on throttle body to full throttle while reading throttle valve opening on hand-held tester which is accessed by THROTTLE POS under CURRENT DATA. Throttle lever will also rotate accelerator pedal position sensor. Throttle valve opening should be 60 percent or more.
7. If throttle valve opening is at least 60 percent, go to step 10. If throttle valve opening is not at least 60 percent, problem may exist in accelerator pedal position sensor, wiring circuit or ECM. Go to step 16 for testing of accelerator pedal position sensor. For wiring of accelerator pedal position sensor, see ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
8. Access ECM. ECM is located on inside of firewall, directly behind driver's seat and luggage compartment. For illustration of ECM location (Scheme 325) To remove components for access to ECM, see «ENGINE CONTROL MODULE»(ref-151983-S05011669822003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION - 4-CYLINDER article.
9. Ensure ignition is on. Using voltmeter, check voltage between ECM terminals VPA and E2 with accelerator pedal released and with accelerator pedal fully depressed. (Scheme 748) Voltage should.3-.9 volt with accelerator pedal released and 3.2-4.7 volts with accelerator pedal fully depressed. If voltage is within specification, go to next step. If voltage is not within specification, problem may exist in accelerator pedal position sensor, wiring circuit or ECM. For testing of accelerator pedal position sensor, go to step 16. For wiring of accelerator pedal position sensor, see ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
10. Start engine and allow engine to idle. Check operation of Malfunction Indicator Light (MIL) on instrument panel. MIL is displayed as an engine icon. If MIL is not illuminated, go to next step. If MIL is illuminated, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.
11. To test operation of air assist system, allow engine to warm to normal operating temperature. Apply parking brake. Place transaxle in Neutral. Ensure A/C is off. Note engine idle speed. Engine idle speed should be 700-800 RPM. If all previous steps have been performed, drive vehicle to verify proper operation of throttle body.
12. To test throttle control motor, disconnect electrical connector at throttle control motor. (Scheme 747) It may be necessary to remove throttle body for access to electrical connector at throttle control motor. If necessary to remove throttle body, see «THROTTLE BODY»(ref-151983-S27294477362003010900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - 4-CYLINDER article.
13. Note terminal identification on throttle control motor. (Scheme 749) Using ohmmeter, check resistance between specified terminals on throttle control motor. See «THROTTLE CONTROL MOTOR RESISTANCE»(ref-151978-S18519848662003010900000) table. If resistance is within specification, reinstall electrical connector. Go to next step. If resistance is not within specification, replace throttle body with throttle control motor as an assembly. THROTTLE CONTROL MOTOR RESISTANCE Terminal No. Ohms @ 68°F (20°C) 1 & 2.3-100.0 3 & 4 4.2-5.2
14. To test TP sensor, it may be necessary to remove throttle body for access to electrical connector at TP sensor. If necessary to remove throttle body, see «THROTTLE BODY»(ref-151983-S27294477362003010900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - 4-CYLINDER article.
15. Disconnect electrical connector at TP sensor. (Scheme 747) Using ohmmeter, check resistance between terminals E2 and VC on TP sensor. (Scheme 750) Replace TP sensor if resistance is not 1200-3200 ohms at 68°F (20°C). See «THROTTLE BODY»(ref-151983-S27294477362003010900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - 4-CYLINDER article.
16. To test accelerator pedal position sensor, it may be necessary to remove throttle body for access to electrical connector at TP sensor. If necessary to remove throttle body, see «THROTTLE BODY»(ref-151983-S27294477362003010900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - 4-CYLINDER article.
17. Disconnect electrical connector at accelerator pedal position sensor. (Scheme 747) Using ohmmeter, check resistance between terminals E2 and VC on accelerator pedal position sensor. (Scheme 751) Replace accelerator pedal position sensor if resistance is not 1200-3200 ohms at 68°F (20°C). See «THROTTLE BODY»(ref-151983-S27294477362003010900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - 4-CYLINDER article.

Scheme 746

Scheme 747

Scheme 748

Scheme 749

Scheme 750

On Prius the throttle body is part of the Electronic Throttle Control System (ETCS). The ETCS is used for controlling idle speed. ETCS consists of throttle body, accelerator pedal position sensor, Throttle Position (TP) sensor, throttle control motor, Hybrid Vehicle Control Electronic Control Unit (HV ECU) and Engine Control Module (ECM). For throttle body inspection (Scheme 752)- (Scheme 754).

Scheme 751

Scheme 752

Scheme 753

For throttle body inspection (Scheme 755)- see scheme 458.

Scheme 754

Scheme 755

IGNITION SYSTEMS

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

See KNOCK SENSOR under ENGINE SENSORS & SWITCHES.

EXHAUST GAS RECIRCULATION SYSTEM

Note. Manufacturer does not supply EGR information for other 4 cylinder equipped models.

System Check (Tacoma)

1. Remove cap and filter from top of EGR vacuum modulator. (Scheme 756) Ensure filter is clean and in good condition. Clean filter with compressed air (if necessary).
2. Reinstall filter and cap. Ensure filter is installed in EGR vacuum modulator with coarse side facing upward, away from EGR vacuum modulator. Using 3-way connector, install vacuum gauge in vacuum hose between top of EGR valve and EGR vacuum modulator. Perform STEP 1 in illustration. (Scheme 757) Start engine. Ensure engine idles smoothly to ensure proper seating of EGR valve. Shut engine off.
3. Connect Toyota hand-held tester or scan tool to data link connector No. 3 located at driver's side of instrument panel. (Scheme 541) Hand-held tester or scan tool is used to read engine RPM. To test operation of EGR Vacuum Switching Valve (VSV) with engine cold, ensure engine coolant temperature is less than 122°F (50°C). Start engine. 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 Toyota hand-held tester to operate EGR VSV, or by connecting vacuum hose from port "Q" on EGR vacuum modulator to EGR valve. If using hand-held tester, go to next step. If hand-held tester is not available, go to step 6.
5. Select ACTIVE TEST MODE on hand-held tester so EGR VSV is closed. Start engine. Operate engine at 3500 RPM. Ensure a low vacuum reading is obtained on vacuum gauge with engine speed at 3500 RPM. Shut engine off. Remove hand-held tester, vacuum gauge and reconnect vacuum hoses. 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 in illustration. (Scheme 757) 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 directly to EGR valve. (Scheme 758) This will by-pass EGR VSV. Start engine. Operate engine at 3500 RPM. Ensure a low vacuum reading is obtained on vacuum gauge with engine speed at 3500 RPM. Shut engine off. Remove vacuum gauge and reconnect vacuum hoses. Go to next step.
8. To check EGR valve operation, remove and plug vacuum 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 756

Scheme 757

EGR Gas Temperature Sensor (Tacoma)

See EGR GAS TEMPERATURE SENSOR under ENGINE SENSORS & SWITCHES.

EGR Vacuum Modulator (Tacoma)

1. When testing EGR vacuum modulator, it may be necessary to monitor engine RPM by using Toyota hand-held tester or scan tool. Toyota hand-held tester or scan tool may be connected to data link connector No. 3 located at driver's side of instrument panel for monitoring engine RPM. (Scheme 541)
2. Locate EGR vacuum modulator and mark vacuum hose locations and disconnect vacuum hoses from EGR vacuum modulator. (Scheme 756)and (Scheme 758).
3. Block ports "P" and "R" on EGR vacuum modulator. (Scheme 758) 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.
4. Apply air pressure to port "Q". (Scheme 758) Air should flow freely through air filter side of EGR vacuum modulator.
5. Start engine and operate engine at 3500 RPM. Repeat test procedures in steps 3 and 4. 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.

Scheme 758

1. Disconnect electrical connector from EGR Vacuum Switching Valve (VSV). (Scheme 756) EGR VSV is located on bracket, near throttle body.
2. Using ohmmeter, check that continuity exists between electrical terminals on EGR VSV and that resistance is 33-39 ohms at 68°F (20°C). Replace EGR VSV if no continuity exists or resistance is not within specification.
3. 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.
4. To test EGR VSV operation, apply air pressure to port "E". Ensure air does not flow from port "F". Perform STEP 1 in illustration. (Scheme 759)
5. Apply battery voltage and ground to electrical terminals on EGR VSV. Apply air pressure to port "E". Ensure air flows from port "F". Perform STEP 2 in illustration. (Scheme 759) Replace EGR VSV if defective.

EGR Valve (Tacoma 3RZ-FE)

1. Remove EGR valve. See «EGR VALVE»(ref-151983-S01373377392003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL & 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.

HYDROCARBON ABSORBER CATALYST SYSTEM (PRIUS)

Note. Hydrocarbon absorber catalyst system may also be referred to as HCAC system.

Hydrocarbon Absorber Catalyst System Check

For hydrocarbon absorber catalyst system check (Scheme 760)- (Scheme 762).

Scheme 759

Scheme 760

Scheme 761

HCAC Vacuum Switching Valve

For HCAC vacuum switching valve inspection and testing (Scheme 763)and see scheme 476.

Scheme 762

Scheme 763

FUEL EVAPORATIVE SYSTEM

Note. Fuel evaporative system is referred to as fuel EVAP system and may contain different components depending on application. see scheme 459- (Scheme 756). When testing fuel EVAP system components, use proper illustration to determine component location. On Camry and Highlander, illustration was not available from manufacturer.

Note. On all models, 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. see scheme 459- (Scheme 756). 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. Manufacturer provides testing information for testing airtightness of fuel tank and components along with testing of charcoal canister and fuel EVAP system.

Canister Closed Valve Vacuum Switching Valve (Camry Except PZEV)

For canister closed valve vacuum switching valve test on Camry without Partial Zero Emission Vehicle (PZEV) option (Scheme 765)- (Scheme 766).

Scheme 764

Scheme 765

Canister Closed Valve Vacuum Switching Valve (Camry PZEV)

For canister closed valve vacuum switching valve test on Camry with Partial Zero Emission Vehicle (PZEV) option (Scheme 767)- (Scheme 768).

Scheme 766

Scheme 767

Canister Closed Valve Vacuum Switching Valve (Celica)

For canister closed valve vacuum switching valve test (Scheme 769)

Scheme 768

Canister Closed Valve Vacuum Switching Valve (Corolla)

For canister closed valve vacuum switching valve test (Scheme 770)

Scheme 769

Canister Closed Valve Vacuum Switching Valve (ECHO)

For canister closed valve vacuum switching valve test (Scheme 771)

Scheme 770

Canister Closed Valve Vacuum Switching Valve (Highlander)

For canister closed valve vacuum switching valve test (Scheme 772)

Scheme 771

Canister Closed Valve Vacuum Switching Valve (Matrix)

For canister closed valve vacuum switching valve test, see FUEL EVAP SYSTEM TEST (MATRIX WITH 1ZZ-FE ENGINE) or FUEL EVAP SYSTEM TEST (MATRIX WITH 2ZZ-GE ENGINE) .

Canister Closed Valve Vacuum Switching Valve (MR2)

For canister closed valve vacuum switching valve test (Scheme 773)

Scheme 772

Canister Closed Valve Vacuum Switching Valve (Prius)

For canister closed valve vacuum switching valve test (Scheme 774)- (Scheme 775).

Scheme 773

Scheme 774

Canister Closed Valve Vacuum Switching Valve (RAV4)

For canister closed valve vacuum switching valve test (Scheme 776)

Scheme 775

Canister Closed Valve Vacuum Switching Valve (Tacoma)

For canister closed valve vacuum switching valve test (Scheme 777)

Scheme 776

Charcoal Canister (Camry Except PZEV)

For testing of charcoal canister on Camry without Partial Zero Emission Vehicle (PZEV) option (Scheme 778)- (Scheme 779).

Scheme 777

Scheme 778

Charcoal Canister (Camry PZEV)

For testing of charcoal canister on Camry with Partial Zero Emission Vehicle (PZEV) option (Scheme 780)- (Scheme 783).

Scheme 779

Scheme 780

Scheme 781

Scheme 782

Charcoal Canister (Camry Solara)

For testing of charcoal canister, see FUEL EVAP SYSTEM TEST (CAMRY SOLARA) .

Charcoal Canister (Celica)

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

Charcoal Canister (Corolla)

For testing of charcoal canister (Scheme 784)- (Scheme 785).

Scheme 783

Scheme 784

Charcoal Canister (ECHO)

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

Charcoal Canister (Highlander)

For testing of charcoal canister (Scheme 786)- (Scheme 787).

Scheme 785

Scheme 786

Charcoal Canister (Matrix With 1ZZ-FE Engine)

For testing of charcoal canister (Scheme 788)- (Scheme 790).

Scheme 787

Scheme 788

Scheme 789

Charcoal Canister (Matrix With 2ZZ-GE Engine)

For testing of charcoal canister (Scheme 791)- (Scheme 792).

Scheme 790

Scheme 791

Charcoal Canister (MR2)

For testing of charcoal canister, see FUEL EVAP SYSTEM TEST (MR2) .

Charcoal Canister (Prius)

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

Charcoal Canister (RAV4)

For testing of charcoal canister, see FUEL EVAP SYSTEM TEST (RAV4) .

Charcoal Canister (Tacoma)

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

Cut-Off Valve

Note. Prius is not equipped with a cut-off valve.

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 (All Models)

1. Remove EVAP Vacuum Switching Valve (VSV). For location of EVAP VSV, see «EVAP VACUUM SWITCHING VALVE LOCATION»(ref-151978-S27952536872003010900000) table and see scheme 459 - (Scheme 756). EVAP VACUUM SWITCHING VALVE LOCATION Application Location Camry On Air Cleaner Housing & Contains 2-Pin Electrical Connector With Black/White & Black/Red Wires Camry Solara On Air Intake Hose, Near Air Cleaner Assembly & Contains 2-Pin Electrical Connector With Black/White & Black/Red Wires Celica On Bracket At Rear Of Air Cleaner Housing & Contains 2-Pin Electrical Connector With Green/Orange & Black/White Wires Corolla On Bracket At Rear Of Air Cleaner Housing & Contains 2-Pin Electrical Connector With Blue/Black & Black Wires ECHO On Bracket At Side Of Air Cleaner Housing & Contains 2-Pin Electrical Connector With Black & White/Green Wires Highlander On Rear Of Air Cleaner Housing & Contains 2-Pin Electrical Connector With Black/White & Black/Red Wires Matrix On Bracket At Rear Of Air Cleaner Housing & Contains 2-Pin Electrical Connector With Blue/Black & Black Wires MR2 On Air Intake Hose, Near Air Cleaner Assembly & Contains 2-Pin Electrical Connector With Black/Red & White Wires Prius At Passenger's Side Front Corner Of Engine Compartment, Near Air Intake Hose & Contains 2-Pin Electrical Connector With Red/Blue & Black Wires RAV4 On Air Intake Hose, Near Air Cleaner Assembly & Contains 2-Pin Electrical Connector With Black/Red & Pink Wires Tacoma On Bracket Bolted To Inside Of Driver's Side Front Fender Panel & Contains 2-Pin Electrical Connector With White/Green & White/Red Wires
2. Using ohmmeter, ensure continuity exists between electrical terminals on EVAP VSV and that resistance is within specification. See «EVAP VACUUM SWITCHING VALVE RESISTANCE»(ref-151978-S20692193142003010900000) table. Replace EVAP VSV if no continuity exists or resistance is not within specification. EVAP VACUUM SWITCHING VALVE RESISTANCE Application Ohms @ 68°F (20°C) Camry & Camry Solara, Highlander, RAV4 & Tacoma 30-34 Celica, Corolla, ECHO, Matrix, MR2 & Prius 27-33
3. Using ohmmeter, ensure no continuity exists between each electrical terminal and body of EVAP VSV. Replace EVAP VSV if continuity exists between electrical terminal and body of EVAP VSV.
4. To test EVAP VSV operation, apply air pressure to port "E". Ensure air does not flow from port "F". Perform STEP 1 in illustration. (Scheme 793)- (Scheme 797).
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 in illustration. (Scheme 793)- (Scheme 797). Replace EVAP VSV if defective.

Scheme 792

Scheme 793

Scheme 794

Scheme 795

Scheme 796

Overfill Check Valve

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.

Pressure Switching Valve Vacuum Switching Valve (Camry, Camry Solara, Celica, Corolla, Highlander, MR2, RAV4 & Tacoma)

1. Remove pressure switching valve Vacuum Switching Valve (VSV). For pressure switching valve VSV location, see «PRESSURE SWITCHING VALVE VACUUM SWITCHING VALVE LOCATION»(ref-151978-S03042826142003010900000) table and see scheme 459 - (Scheme 756). PRESSURE SWITCHING VALVE VACUUM SWITCHING VALVE LOCATION Application Location Camry On Bracket At Charcoal Canister Near Fuel Tank & Contains 2-Pin Electrical Connector With Violet & Black/Red Wires Camry Solara On Bracket At Charcoal Canister Near Fuel Tank & Contains 2-Pin Electrical Connector With White/Red & Red Wires Celica On Bracket At Charcoal Canister Near Fuel Tank & Contains 2-Pin Electrical Connector With Green/Orange & Black/White Wires Corolla On Bracket At Charcoal Canister Near Fuel Tank & Contains 2-Pin Electrical Connector With Red & Black Wires Highlander On Bracket At Charcoal Canister Near Fuel Tank & Contains 2-Pin Electrical Connector With White & Green/Yellow Wires Matrix (1) MR2 Below Driver's Side Luggage Compartment, On Bracket At Charcoal Canister Near Fuel Tank & Contains 2-Pin Electrical Connector With Blue/White & Black/Red Wires RAV4 On Bracket At Charcoal Canister Near Fuel Tank & Contains 2-Pin Electrical Connector With Green/Orange & Black/Red Wires Tacoma On Bracket At Charcoal Canister Near Fuel Tank & Contains 2-Pin Electrical Connector With Green/Black & White/Red Wires (1) On 2WD, pressure switching valve vacuum switching valve is located on bracket at charcoal canister near fuel tank. On 4WD, pressure switching valve vacuum switching valve is located on passenger side of fuel tank both contain 2-pin electrical connector with Red & Black wires.
2. Using ohmmeter, ensure continuity exists between electrical terminals on pressure switching valve VSV and that resistance is within specification. See «PRESSURE SWITCHING VALVE VACUUM SWITCHING VALVE RESISTANCE»(ref-151978-S33121207802003010900000) table. Replace pressure switching valve VSV if no continuity exists or resistance is not within specification. PRESSURE SWITCHING VALVE VACUUM SWITCHING VALVE RESISTANCE Application Ohms @ 68°F (20°C) Camry, Highlander, MR2, RAV4 & Tacoma 30-36 Camry Solara & Celica (1) Corolla & Matrix 37-44 (1) Resistance should be 37-44 ohms at 68°F (20°C) and 51-62 ohms at 248 °F (120°C).
3. Ensure no continuity exists between each electrical terminal and body of pressure switching valve VSV. Replace pressure switching valve VSV if continuity exists between electrical terminal and body of pressure switching valve VSV.
4. To test pressure switching valve VSV operation, apply air pressure to port "E". Ensure air does not flow from port "F". Perform STEP 1 in illustration. (Scheme 798)- (Scheme 800).
5. Apply battery voltage and ground to electrical terminals on pressure switching valve VSV. Apply air pressure to port "E". Ensure air flows from port "F". Perform STEP 2 in illustration. (Scheme 798)- (Scheme 800). Replace pressure switching valve VSV if defective.

Scheme 797

Scheme 798

Scheme 799

Purge Flow Switching Valve Vacuum Switching Valve (Prius)

1. Remove purge flow switching valve Vacuum Switching Valve (VSV). Purge flow switching valve VSV is located on bracket at charcoal canister on top of fuel tank and contains Blue 2-pin electrical connector with Black and Black/Red wires. see scheme 466 If necessary to remove fuel tank for access to purge flow switching valve VSV, see «FUEL PUMP»(ref-151983-S17683362262003010900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - 4-CYLINDER article for removal of fuel tank.
2. Using ohmmeter, ensure continuity exists between electrical terminals on purge flow switching valve VSV and that resistance is 33-39 ohms at 68°F (20°C). Replace purge flow switching valve VSV if no continuity exists or resistance is not within specification.
3. Ensure no continuity exists between each electrical terminal and body of purge flow switching valve VSV. Replace purge flow switching valve VSV if continuity exists between electrical terminal and body of purge flow switching valve VSV.
4. To test purge flow switching valve VSV operation, apply air pressure to port "E". Ensure air flows from port "F" and not from port "G". Perform STEP 1 in illustration. (Scheme 801)
5. Apply battery voltage and ground to electrical terminals on purge flow switching valve VSV. Apply air pressure to port "G". Ensure air flows from port "F" and not from port "E". Perform STEP 2 in illustration. (Scheme 801) Replace purge flow switching valve VSV if defective.

Scheme 800

Vapor Pressure Sensor (Camry Except PZEV)

For testing of vapor pressure sensor on Camry without Partial Zero Emission Vehicle (PZEV) option (Scheme 802)- (Scheme 803). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

Scheme 801

Scheme 802

Vapor Pressure Sensor (Camry PZEV)

For testing of vapor pressure sensor on Camry with Partial Zero Emission Vehicle (PZEV) option (Scheme 804)

Scheme 803

Vapor Pressure Sensor (Camry Solara)

For testing of vapor pressure sensor (Scheme 805)

Scheme 804

Scheme 805

1. Ensure ignition is off. To test vapor pressure sensor supply voltage, remove rear seat cushion and cover plate for access to electrical connector at vapor pressure sensor. On Celica, vapor pressure sensor is located on top of fuel pump assembly on top of fuel tank and contains 3-pin electrical connector with Brown, Red and Blue/Black wires. (Scheme 806) On ECHO, vapor pressure sensor is located on top of fuel pump assembly on top of fuel tank and contains 3-pin electrical connector with Brown, Red/White and Black wires. (Scheme 806)
2. On all models, disconnect electrical connector from vapor pressure sensor. Turn ignition on. Using voltmeter, measure vapor pressure sensor supply voltage between terminals No. 1 and 3 on wiring harness side of electrical connector for vapor pressure sensor. (Scheme 806) DO NOT use center terminal. Vapor pressure sensor supply voltage should be 4.5-5.5 volts.
3. If vapor pressure sensor supply voltage is within specification, turn ignition off. Reinstall electrical connector on vapor pressure sensor. Go to next step. If vapor pressure sensor supply voltage is not within specification, check wiring circuit between Engine Control Module (ECM) and vapor pressure sensor. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. On Celica, ECM is located in engine compartment, below cover, just in front of battery, next to driver's side strut tower. On ECHO, ECM is located behind glove box. On all models, for illustration of ECM location, see «ENGINE CONTROL MODULE»(ref-151978-S08085117732003080600000) under COMPONENT LOCATIONS. For information on accessing ECM, see «ENGINE CONTROL MODULE»(ref-151983-S05011669822003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION - 4-CYLINDER article.
4. To test vapor pressure sensor output voltage, ensure electrical connector is installed on vapor pressure sensor. Turn ignition on. Remove fuel tank cap. Using voltmeter, measure vapor pressure sensor output voltage between terminals No. 2 and 3 on wiring harness side of electrical connector for vapor pressure sensor with electrical connector installed on vapor pressure sensor. (Scheme 806)
5. Vapor pressure sensor output voltage should be 3.0-3.6 volts. Replace vapor pressure sensor if vapor pressure sensor output voltage is not within specification. Turn ignition off. Reinstall fuel tank cap, cover plate and rear seat cushion.

Vapor Pressure Sensor (Corolla)

For testing of vapor pressure sensor (Scheme 807) Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

Scheme 806

Vapor Pressure Sensor (Highlander)

For testing of vapor pressure sensor (Scheme 808)- (Scheme 809). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

Scheme 807

Scheme 808

Vapor Pressure Sensor (Matrix)

For testing of vapor pressure sensor (Scheme 810) Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS.

Scheme 809

Vapor Pressure Sensor (MR2)

For testing of vapor pressure sensor (Scheme 811)

Scheme 810

Vapor Pressure Sensor (Prius)

Scheme 811

1. Ensure ignition is off. To test vapor pressure sensor supply voltage, disconnect electrical connector at vapor pressure sensor. Vapor pressure sensor is located on top of fuel tank and contains 3-pin electrical connector with Brown, Blue/Red and Yellow/Red wires. (Scheme 812) It may be necessary to lower fuel tank for access to electrical connector at vapor pressure sensor.
2. Disconnect electrical connector from vapor pressure sensor. Turn ignition on. Using voltmeter, measure vapor pressure sensor supply voltage between terminals No. 1 and 3 on wiring harness side of electrical connector for vapor pressure sensor. (Scheme 812) DO NOT use center terminal. Vapor pressure sensor supply voltage should be 4.5-5.5 volts.
3. If vapor pressure sensor supply voltage is within specification, turn ignition off. Reinstall electrical connector on vapor pressure sensor. Go to next step. If vapor pressure sensor supply voltage is not within specification, check wiring circuit between Engine Control Module (ECM) and vapor pressure sensor. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. ECM is located behind glove box. For illustration of ECM location, see «ENGINE CONTROL MODULE»(ref-151978-S08085117732003080600000) under COMPONENT LOCATIONS.
4. To test vapor pressure sensor output voltage, ensure electrical connector is installed on vapor pressure sensor. Turn ignition on. Remove fuel tank cap. Using voltmeter, measure vapor pressure sensor output voltage between terminals No. 2 and 3 on wiring harness side of electrical connector for vapor pressure sensor with electrical connector installed on vapor pressure sensor. (Scheme 812)
5. Vapor pressure sensor output voltage should be 3.0-3.6 volts. Replace vapor pressure sensor if vapor pressure sensor output voltage is not within specification. Turn ignition off. Reinstall fuel tank cap.

Vapor Pressure Sensor (RAV4)

For testing of vapor pressure sensor (Scheme 813)

Scheme 812

Scheme 813

Scheme 814

1. Ensure ignition is off. To test vapor pressure sensor supply voltage, disconnect electrical connector from vapor pressure sensor. Vapor pressure sensor is located on top of fuel pump assembly on top of fuel tank and contains Black 3-pin electrical connector with Green/Yellow, Red/Yellow and Blue/Black wires. (Scheme 814)
2. Turn ignition on. Using voltmeter, measure vapor pressure sensor supply voltage between terminals VC and E2 on wiring harness side of electrical connector for vapor pressure sensor. (Scheme 814) DO NOT use center terminal. Vapor pressure sensor supply voltage should be 4.5-5.5 volts.
3. If vapor pressure sensor supply voltage is within specification, turn ignition off. Reinstall electrical connector on vapor pressure sensor. Go to next step. If vapor pressure sensor supply voltage is not within specification, check wiring circuit between Engine Control Module (ECM) and vapor pressure sensor. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. ECM is located behind the glove box. For illustration of ECM location, see «ENGINE CONTROL MODULE»(ref-151978-S08085117732003080600000) under COMPONENT LOCATIONS. For information on accessing ECM, see «ENGINE CONTROL MODULE»(ref-151983-S05011669822003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION - 4-CYLINDER article.
4. To test vapor pressure sensor output voltage, turn ignition on. Ensure electrical connector is installed on vapor pressure sensor. Remove fuel tank cap. Using voltmeter, check voltage between ECM terminals E2 (Brown wire) and PTNK (Red/Yellow wire). (Scheme 815) Vapor pressure sensor output voltage should be 3.0-3.6 volts. Replace vapor pressure sensor if vapor pressure sensor output voltage is not within specification. Turn ignition off. Reinstall fuel tank cap.

Camry & Highlander

1. Remove Positive Crankcase Ventilation (PCV) valve. PCV valve is located at passenger's side front corner of valve cover, just above intake manifold. Apply air pressure to PCV valve at bottom (cylinder head side) of PCV valve. Ensure air flows easily through PCV valve.
2. Apply air pressure to PCV valve at vacuum side (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 Solara, Celica, Corolla, ECHO, MR2, Prius, RAV4 & Tacoma

For Positive Crankcase Ventilation (PCV) valve test (Scheme 816)

Scheme 815

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

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

Scheme 816

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See «IDLE SPEED & MIXTURE»(ref-151948-S09844152842003010900000) in ON-VEHICLE ADJUSTMENTS - 4-CYLINDER article.
2. With engine idling, disconnect and plug vacuum hose at throttle opener. (Scheme 817) Note engine speed with vacuum hose disconnected from throttle opener. Engine speed should be 1200-1500 RPM.
3. Throttle opener is nonadjustable. If engine speed is not within specification, replace throttle body. See «THROTTLE BODY»(ref-151983-S27294477362003010900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - 4-CYLINDER article. Shut engine off. Reinstall vacuum hose on throttle opener. Start engine and ensure engine returns to proper idle speed.

VARIABLE VALVE LIFT SYSTEM

Note. Variable Valve Lift (VVL) system may also be referred to as Variable Valve Timing Lift Intelligent (VVTL-I or VVTL-i) system.

Note. If problem exists in VVL system, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

VARIABLE VALVE LIFT OIL CONTROL VALVE

Note. Variable Valve Lift (VVL) oil control valve may also be referred to as VVL Oil Control Valve (OCV) or camshaft timing oil control valve (VVL).

For testing of Variable Valve Lift (VVL) oil control valve (Scheme 818)- (Scheme 819).

Scheme 817

Scheme 818

For testing of Variable Valve Lift (VVL) oil control valve (Scheme 820)- (Scheme 821).

Scheme 819

Scheme 820

1. Remove No. 2 cylinder head cover located on top of engine, above ignition coils and valve cover. To check VVL oil control valve resistance, disconnect electrical connector at VVL oil control valve. VVL oil control valve is located at intake manifold side of cylinder head, near flywheel end of engine. (Scheme 822)
2. Using ohmmeter, check resistance between electrical terminals on VVL oil control valve. Resistance should be 6.9-7.9 ohms at 68°F (20°C). If resistance is within specification, go to next step. If resistance is not within specification, replace VVL oil control valve. See «VARIABLE VALVE LIFT OIL CONTROL VALVE»(ref-151983-S05835268252003010900000) under VARIABLE VALVE LIFT SYSTEM in REMOVAL & INSTALLATION - 4-CYLINDER article.
3. To check VVL oil control valve operation, remove VVL oil control valve. See «VARIABLE VALVE LIFT OIL CONTROL VALVE»(ref-151983-S05835268252003010900000) under VARIABLE VALVE LIFT SYSTEM in REMOVAL & INSTALLATION - 4-CYLINDER article.
4. Note movement of valve inside VVL oil control valve while applying and disconnecting battery voltage and ground to terminals No. 1 and 2 on VVL oil control valve. (Scheme 823) Valve should move outward toward end of assembly opposite electrical connector with voltage applied and should move inward toward electrical connector end of assembly with voltage not applied. (Scheme 823) Replace VVL oil control valve if operation is not as specified.

Scheme 821

Scheme 822

Corolla, Highlander, Matrix, MR2, Prius & RAV4

For testing of Variable Valve Lift (VVL) oil control valve (Scheme 824)

Scheme 823

For testing of Variable Valve Lift (VVL) oil control valve (Scheme 825)- (Scheme 826).

Scheme 824

Scheme 825

VARIABLE VALVE TIMING SYSTEM

Note. Variable Valve Timing (VVT) system is used on Camry, Camry Solara, Celica, Corolla, ECHO, Highlander, MR2, Prius & RAV4. If problem exists in VVT system, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Camry, Camry Solara, Celica, Corolla, ECHO, Highlander, MR2, Prius & RAV4

Note. Variable Valve Timing (VVT) sensor may also be referred to as camshaft position sensor.

For VVT sensor testing, see CAMSHAFT POSITION SENSOR under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article.

Note. Variable Valve Timing (VVT) camshaft timing oil control valve may also be referred to as oil control valve for VVT, VVT Oil Control Valve (OCV) or camshaft timing oil control valve VVT.

1. Remove No. 2 cylinder head cover located on top of engine, above ignition coils and valve cover (if necessary) for access to VVT camshaft timing oil control valve. VVT camshaft timing oil control valve is located at intake manifold side of cylinder head, near timing chain end of engine. (Scheme 822)- (Scheme 831).. To check VVT camshaft timing oil control valve resistance, disconnect electrical connector at VVT camshaft timing oil control valve.
2. Using ohmmeter, check resistance between electrical terminals on VVT camshaft timing oil control valve. Ensure resistance is within specification. See «VVT CAMSHAFT TIMING OIL CONTROL VALVE RESISTANCE»(ref-151978-S21200485202003010900000) table. If resistance is within specification, go to next step. If resistance is not within specification, replace VVT camshaft timing oil control valve. See «VARIABLE VALVE TIMING CAMSHAFT TIMING OIL CONTROL VALVE»(ref-151983-S04717965782003010900000) under VARIABLE VALVE TIMING SYSTEM in REMOVAL & INSTALLATION - 4-CYLINDER article. VVT CAMSHAFT TIMING OIL CONTROL VALVE RESISTANCE Application Ohms @ 68°F (20°C) Camry, Camry Solara, Celica, Corolla, Highlander, MR2, Prius & RAV4 6.9-7.9 ECHO 5.5-12.0
3. To check VVT camshaft timing oil control valve operation, remove VVT camshaft timing oil control valve. See «VARIABLE VALVE TIMING CAMSHAFT TIMING OIL CONTROL VALVE»(ref-151983-S04717965782003010900000) under VARIABLE VALVE TIMING SYSTEM in REMOVAL & INSTALLATION - 4-CYLINDER article.
4. Note movement of valve inside VVT camshaft timing oil control valve while applying and disconnecting battery voltage and ground to terminals No. 1 and 2 on VVT camshaft timing oil control valve. (Scheme 823)and see scheme 612. Valve should move outward toward end of assembly opposite electrical connector with voltage applied, and should move inward toward electrical connector end of assembly with voltage not applied. (Scheme 823)and see scheme 612. Replace VVT camshaft timing oil control valve if operation is not as specified.

Scheme 826

Scheme 827

Scheme 828

Scheme 829

Scheme 830

Scheme 831