Engine Control System & Component Testing - 4-CYLINDER: Other Toyota Corolla IX

PRIUS

The following service precautions must be followed

Scheme 120

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 120) 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.

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. 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.

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

Scheme 121

Scheme 122

1. Remove necessary components for access to ACIS VSV. ACIS VSV is located on bottom of air cleaner case. (Scheme 121)
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 122)
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 122) Replace ACIS VSV if defective. Reinstall ACIS VSV.

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, MR2 With Sequential Manual Transaxle & Prius

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

Camry, Celica & Highlander

Testing information is not available from manufacturer.

Camry Solara With Manual A/C & MR2

Scheme 123

1. Check A/C compressor drive belt for proper tension. If A/C compressor drive belt has proper belt tension, go to next step. If A/C compressor drive belt does not have proper belt tension, it may be necessary to replace automatic belt tensioner and then go to next step.
2. Start engine and note if A/C compressor locks when blower and A/C switches are in ON position. If A/C compressor does not lock, go to next step. If A/C compressor locks, repair A/C compressor as necessary.
3. Check A/C compressor lock sensor. See «A/C COMPRESSOR LOCK SENSOR»(ref-133221-S22941818392002021900000) under ENGINE SENSORS & SWITCHES. If A/C compressor lock sensor is okay, go to next step. If A/C compressor lock sensor is defective, replace A/C compressor lock sensor.
4. On Camry Solar, remove glove box for access to Engine Control Module (ECM). For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. On MR2, remove luggage compartment lids, luggage compartment boxes and quarter trim panels for access to Engine Control Module (ECM). ECM is located on inside of firewall, directly behind driver's seat and luggage compartment. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. For additional information on removal of luggage compartment components, see «FUEL PUMP»(ref-133226-S07700574872002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
5. On all models, note ECM electrical connector terminals. (Scheme 138)and (Scheme 144). Connect oscilloscope between proper terminals on ECM for A/C compressor lock sensor. See «ECM TERMINAL IDENTIFICATION & CIRCUIT IDENTIFICATION FOR A/C COMPRESSOR LOCK SENSOR»(ref-133221-S31338765022002021900000) table. These are the LCK1 and E1 terminals at ECM. ECM TERMINAL IDENTIFICATION & CIRCUIT IDENTIFICATION FOR A/C COMPRESSOR LOCK SENSOR Application ECM Connector ECM Terminal No. (Wire Color) Camry Solara E9 (1) 23 (White/Blue) E9 (2) 1 (Brown) MR2 E3 (1) 28 (White/Red) E4 (2) 17 (Brown) (1) This is the A/C compressor lock sensor signal circuit at ECM. (2) This is the ground circuit at ECM.
6. Check A/C compressor lock sensor wave pattern on oscilloscope during cranking or with engine idling. A/C compressor lock sensor wave pattern should switch from between zero volts and.2 volts within 20 milliseconds. (Scheme 123) If A/C compressor lock sensor wave pattern is as specified, go to next step. If A/C compressor lock sensor wave pattern is not at specified, replace A/C compressor lock sensor.
7. On Camry Solara, go to next step. On MR2, check A/C compressor clutch relay. See «A/C COMPRESSOR CLUTCH RELAY»(ref-133221-S14032007562002021900000) under MODULES, MOTORS, RELAYS & SOLENOIDS. If A/C compressor clutch relay is okay, go to next step. If A/C compressor clutch relay is defective, replace A/C compressor clutch relay.
8. On all models, check wiring harness and electrical connectors for A/C compressor lock sensor between ECM and A/C compressor lock sensor for any problems. See «ECM TERMINAL IDENTIFICATION & CIRCUIT IDENTIFICATION FOR A/C COMPRESSOR LOCK SENSOR»(ref-133221-S31338765022002021900000) table. If wiring harness or electrical connector is defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. If ECM is replaced and vehicle is equipped with engine immobilizer system, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

RAV4

Scheme 124

1. Remove glove box for access to Engine Control Module (ECM). ECM is located near passenger's side kick panel, just below instrument panel. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. Note terminals on ECM electrical connector. (Scheme 146)
2. Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 15 (Red/Yellow or White wire) at ECM electrical connector E7. This is the ACMG terminal on ECM. There are 2 different wiring harnesses used. Wire color at designated terminal may vary according to wiring harness used. Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, check Red/Yellow or White wire and electrical connector between ECM and terminal No. 3 (Red/Yellow or White wire) at electrical connector 3S on passenger's side junction block Electronic Control Unit (ECU). (Scheme 124)
3. Check A/C compressor drive belt for proper tension. If A/C compressor drive belt has proper belt tension, go to next step. If A/C compressor drive belt does not have proper belt tension, it may be necessary to replace automatic belt tensioner and then go to next step.
4. Start engine and note if A/C compressor locks when blower and A/C switches are in ON position. If A/C compressor does not lock, go to next step. If A/C compressor locks, repair A/C compressor as necessary.
5. Check A/C compressor lock sensor. See «A/C COMPRESSOR LOCK SENSOR»(ref-133221-S22941818392002021900000) under ENGINE SENSORS & SWITCHES. If A/C compressor lock sensor is okay, go to next step. If A/C compressor lock sensor is defective, replace A/C compressor lock sensor.
6. Check wiring harness and electrical connectors between A/C compressor lock sensor, passenger's side junction block ECU, A/C amplifier and ECM. See WIRING DIAGRAMS in appropriate article in AIR CONDITIONING & HEATING. A/C amplifier is located behind center of instrument panel. (Scheme 124) If wiring harness or electrical connector is defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. On models equipped with engine immobilizer system, if ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

Highlander, MR2 & RAV4

Testing information is not available from manufacturer.

Scheme 125

1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step 10.
2. Connect hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 130) Turn ignition on and then turn hand-held tester on. Start engine and turn A/C switch to ON position. Ensure A/C clutch engages.
3. Select ACTIVE TEST MODE on hand-held tester. Check operation of A/C clutch when A/C-cut control is operated by hand-held tester. A/C clutch should turn off (stop operating) when A/C-cut control is operated by hand-held tester. If A/C clutch does not operate properly, go to next step. If A/C clutch operates properly, shut engine off. Remove hand-held tester. Diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
4. Check for open and short in wiring harness and electrical connectors between Engine Control Module (ECM) and A/C amplifier. See WIRING DIAGRAMS in appropriate article in AIR CONDITIONING & HEATING. ECM is located behind stereo on instrument panel, just in front of center console. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. A/C amplifier is located behind instrument panel, just above glove box, near center of glove box area. (Scheme 125) If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
5. Remove necessary components for access to ECM. See «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
6. Remove bolts from ECM so electrical connectors can be accessed. Note ECM electrical connector terminals. (Scheme 140)and (Scheme 141).
7. Start engine. On 3-speed A/T and M/T models, using voltmeter, check voltage between body ground and terminal No. 21 (Red/Blue wire) at ECM electrical connector E6 while turning A/C switch from ON to OFF positions. (Scheme 140) This is the ACT terminal at ECM. On 4-speed A/T models, using voltmeter, check voltage between body ground and terminal No. 12 (Red/Blue wire) at ECM electrical connector E10 while turning A/C switch from ON to OFF positions. (Scheme 141) This is the ACT terminal at ECM.
8. On all models, voltage should be 9-14 volts with A/C switch in ON position and less than 1.5 volts with A/C switch in OFF position. If voltage is as specified, go to next step. If voltage is not as specified, check for open and short in wiring harness and electrical connectors between ECM and A/C amplifier. See WIRING DIAGRAMS in appropriate article in AIR CONDITIONING & HEATING. A/C amplifier is located behind instrument panel, just above glove box, near center of glove box area. (Scheme 125) If wiring harness and electrical connectors are okay, replace A/C amplifier. If wiring harness or electrical connector is defective, repair as necessary.
9. Check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.
10. Remove necessary components for access to Engine Control Module (ECM). See «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
11. Remove bolts from ECM so electrical connectors can be accessed on ECM. Note ECM electrical connector terminals. (Scheme 140)and (Scheme 141).
12. Start engine. On 3-speed A/T and M/T models, using voltmeter, check voltage between body ground and terminal No. 21 (Red/Blue wire) at ECM electrical connector E6 while turning A/C switch from ON to OFF positions. This is the ACT terminal at ECM. On 4-speed A/T models, using voltmeter, check voltage between body ground and terminal No. 12 (Red/Blue wire) at ECM electrical connector E10 while turning A/C switch from ON to OFF positions. This is the ACT terminal at ECM.
13. On all models, voltage should be 9-14 volts with A/C switch in ON position and less than 1.5 volts with A/C switch in OFF position. If voltage is not as specified, go to next step. If voltage is as specified, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.
14. Check for open and short in wiring harness and electrical connectors between ECM and A/C amplifier. See WIRING DIAGRAMS in appropriate article in AIR CONDITIONING & HEATING. A/C amplifier is located behind instrument panel, just above glove box, near center of glove box area. (Scheme 125) If wiring harness and electrical connectors are okay, replace A/C amplifier. If wiring harness or electrical connector is defective, repair as necessary.

Scheme 126

1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step 7.
2. Connect hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 134) Turn ignition on and then turn hand-held tester on. Start engine and turn A/C switch to ON position. Ensure A/C clutch engages.
3. Select ACTIVE TEST MODE on hand-held tester. Check operation of A/C clutch when A/C-cut control is operated by hand-held tester. A/C clutch should turn off (stop operating) when A/C-cut control is operated by hand-held tester. If A/C clutch does not operate properly, go to next step. If A/C clutch operates properly, shut engine off. Remove hand-held tester. Diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
4. Check for open and short in wiring harness and electrical connectors between Engine Control Module (ECM) and A/C amplifier. See WIRING DIAGRAMS in appropriate article in AIR CONDITIONING & HEATING. ECM is located behind glove box. (Scheme 126) A/C amplifier is attached to rear of center cluster module control. (Scheme 126) If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
5. Remove ECM with electrical connectors still attached. See «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
6. Note ECM electrical connector terminals. (Scheme 145) Start engine. Using voltmeter, check voltage between body ground and terminal No. 22 (Pink/Green wire) at ECM electrical connector E10 while turning A/C switch from ON to OFF positions. This is the ACT terminal at ECM. Voltage should be 9-14 volts with A/C switch in ON position and less than 1.5 volts with A/C switch in OFF position. If voltage is not as specified, replace A/C amplifier. If voltage is as specified, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.
7. Remove ECM with electrical connectors still attached. ECM is located behind glove box. (Scheme 126) See «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
8. Note ECM electrical connector terminals. (Scheme 145) Start engine. Using voltmeter, check voltage between body ground and terminal No. 22 (Pink/Green wire) at ECM electrical connector E10 while turning A/C switch from ON to OFF positions. This is the ACT terminal at ECM. Voltage should be 9-14 volts with A/C switch in ON position and less than 1.5 volts with A/C switch in OFF position. If voltage is not as specified, go to next step. If voltage is as specified, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.
9. Check for open and short in wiring harness and electrical connectors between ECM and A/C amplifier. See WIRING DIAGRAMS in appropriate article in AIR CONDITIONING & HEATING. A/C amplifier is attached to rear of center cluster module control. (Scheme 126) If wiring harness and electrical connectors are okay, replace A/C amplifier. If wiring harness or electrical connector is defective, repair as necessary.

Testing information is not available from manufacturer.

Camry Solara With Manual A/C

1. Remove glove box for access to Engine Control Module (ECM). For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. Note ECM electrical connector terminals. (Scheme 138)
2. Turn ignition on. Using voltmeter, check voltage between terminal No. 32 (Blue/White wire) at ECM electrical connector E8 and terminal No. 28 (Brown wire) at ECM electrical connector E11. This is the THR and E2 terminals at ECM. Voltage should be 2.2-2.6 volts at 32°F (0°C) and 1.4-1.8 volts at 59°F (15°C). If voltage is not within specification, go to next step. If voltage is within specification, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. If ECM is replaced and vehicle is equipped with engine immobilizer system, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.
3. Check A/C evaporator temperature sensor operation. See «A/C EVAPORATOR TEMPERATURE SENSOR»(ref-133221-S07118252882002032500000) under ENGINE SENSORS & SWITCHES. If A/C evaporator temperature sensor operates properly, go to next step. If A/C evaporator temperature sensor is defective, replace A/C evaporator temperature sensor. For servicing of A/C evaporator temperature sensor, see appropriate article in AIR CONDITIONING & HEATING.
4. Check wiring harness and electrical connectors between ECM and A/C evaporator temperature sensor. See «WIRING DIAGRAMS»(ref-133228) article. It may be necessary to see appropriate MANUAL or AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING for complete wiring diagram. If wiring harness or electrical connector is defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. If ECM is replaced and vehicle is equipped with engine immobilizer system, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

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.

1. Remove glove box for access to Engine Control Module (ECM). For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. Note ECM electrical connector terminals. (Scheme 137)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 1 (Black/Red wire) at ECM electrical connector E6 and No. 1 (Brown wire) at ECM electrical connector E8. This is the +B and E1 terminals at ECM. Voltage should be 9-14 volts. If voltage is not within specification, go to next step. If voltage is within specification, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
3. Turn ignition off. Disconnect electrical connector E8 from ECM. Using ohmmeter, check for continuity between body ground and terminal No. 1 (Brown wire) at ECM electrical connector E8. If continuity exists, reinstall electrical connector E8 at ECM and go to next step. If continuity does not exist, repair open in Brown wire between terminal No. 1 at ECM electrical connector E8 and body ground. See «WIRING DIAGRAMS»(ref-133228) article.
4. Ensure ignition is off. Check for open and short in Black/Red wire between EFI main relay and terminal No. 1 at ECM electrical connector E6. See «WIRING DIAGRAMS»(ref-133228) article. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment. If wiring is okay, go to next step. If wiring is defective, repair as necessary.
5. Turn ignition on. Using voltmeter, check voltage between terminals No. 9 (Black/Orange wire) at ECM electrical connector E6 and No. 1 (Brown wire) at ECM electrical connector E8. This is the IGSW and E1 terminals at ECM. Voltage should be 9-14 volts. If voltage is not within specification, go to next step. If voltage is within specification, go to step 9.
6. Check for defective IG2 fuse. IG2 fuse is located in fuse/relay box at driver's side front corner of engine compartment. If IG2 fuse is okay, go to next step. If IG2 fuse is defective, repair short in wiring harness and components connected to IG2 fuse. See «WIRING DIAGRAMS»(ref-133228) article.
7. Check for defective AM2 fuse. AM2 fuse is located in fuse/relay box at driver's side front corner of engine compartment. If AM2 fuse is okay, go to next step. If AM2 fuse is defective, repair short in wiring harness and components connected to AM2 fuse. See «WIRING DIAGRAMS»(ref-133228) article.
8. Check ignition switch. See «IGNITION SWITCH»(ref-133221-S37155000612001121400000) under ENGINE SENSORS & SWITCHES. If ignition switch is okay, repair wiring harness or electrical connectors between ignition switch and terminal No. 9 (Black/Orange wire) at ECM electrical connector E6. See «WIRING DIAGRAMS»(ref-133228) article. If ignition switch is defective, replace ignition switch. See «IGNITION SWITCH»(ref-133226-S01193468262002051300000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
9. Ensure ignition is on. Using voltmeter, check voltage between terminals No. 8 (Black/White wire) at ECM electrical connector E6 and No. 1 (Brown wire) at ECM electrical connector E8. This is the MREL and E1 terminals at ECM. Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. On models equipped with engine immobilizer system, if ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.
10. Check for defective EFI fuse. EFI fuse is located in fuse/relay box at driver's side front corner of engine compartment. If EFI fuse is okay, go to next step. If EFI fuse is defective, repair short in wiring harness and components connected to EFI fuse. See «WIRING DIAGRAMS»(ref-133228) article.
11. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-133221-S21045574842002021900000) under MODULES, MOTORS, RELAYS & SOLENOIDS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
12. Check for open and short in wiring harness and electrical connectors between terminal No. 8 (Black/White wire) at ECM electrical connector E6 and EFI main relay, and for open in White/Black wire between EFI main relay and body ground. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
13. Check wiring harness and electrical connectors between battery and EFI fuse. See «WIRING DIAGRAMS»(ref-133228) article. Repair wiring harness or and electrical connectors as necessary.

Camry Solara

1. Remove glove box for access to Engine Control Module (ECM). For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. Note ECM electrical connector terminals. (Scheme 138)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 1 (Red wire) at ECM electrical connector E7 and No. 1 (Brown wire) at ECM electrical connector E9. This is the +B and E1 terminals at ECM. Voltage should be 9-14 volts. If voltage is not within specification, go to next step. If voltage is within specification, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
3. Turn ignition off. Check for open in wiring harness and electrical connectors between body ground and terminal No. 1 (Brown wire) at ECM electrical connector E9. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
4. Ensure ignition is off. Check for open and short in Red wire between EFI main relay and terminal No. 1 at ECM electrical connector E7. See «WIRING DIAGRAMS»(ref-133228) article. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment. If wiring is okay, go to next step. If wiring is defective, repair as necessary.
5. Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 9 (Black/Red wire) at ECM electrical connector E7. This is IGSW terminal at ECM. Voltage should be 9-14 volts. If voltage is not within specification, go to next step. If voltage is within specification, go to step 8.
6. Check for defective IGN fuse. IGN fuse is located in fuse box behind driver's side of instrument panel. If IGN fuse is okay, go to next step. If IGN fuse is defective, repair short in wiring harness and components connected to IGN fuse. See «WIRING DIAGRAMS»(ref-133228) article.
7. Check ignition switch. See «IGNITION SWITCH»(ref-133221-S37155000612001121400000) under ENGINE SENSORS & SWITCHES. If ignition switch is defective, replace ignition switch. See IGNITION SWITCH under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. If ignition switch is okay, repair wiring harness or electrical connectors between battery and ignition switch, and between ignition switch and terminal No. 9 (Black/Red wire) at ECM electrical connector E7. See «WIRING DIAGRAMS»(ref-133228) article. If necessary to check AM2 fuse, AM2 fuse is located in fuse/relay box at driver's side front corner of engine compartment.
8. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 8 (Black/Red wire) at ECM electrical connector E7. This is the MREL terminal at ECM. Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. On models equipped with engine immobilizer system, if ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.
9. Check for defective EFI fuse. EFI fuse is located in fuse/relay box at driver's side front corner of engine compartment. If EFI fuse is okay, go to next step. If EFI fuse is defective, repair short in wiring harness and components connected to EFI fuse. See «WIRING DIAGRAMS»(ref-133228) article.
10. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-133221-S21045574842002021900000) under MODULES, MOTORS, RELAYS & SOLENOIDS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
11. Check for open and short in wiring harness and electrical connectors between terminal No. 8 (Black/Red wire) at ECM electrical connector E7 and EFI main relay, and for open in White/Black wire between EFI main relay and body ground. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
12. Check wiring harness and electrical connectors between battery and EFI fuse. See «WIRING DIAGRAMS»(ref-133228) article. Repair wiring harness or and electrical connectors as necessary.

1. Remove cover for access to Engine Control Module (ECM). ECM is located in engine compartment, below cover, just in front of battery, next to driver's side strut tower. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. Note ECM electrical connector terminals. (Scheme 139)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 16 (Black/Red wire) at ECM electrical connector E2 and No. 17 (Brown wire) at ECM electrical connector E4. This is the +B and E1 terminals at ECM. Voltage should be 9-14 volts. If voltage is within specification, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article. If voltage is not within specification, check for open in wiring harness and electrical connectors between terminal No. 17 (Brown wire) at ECM electrical connector E4 and body ground. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
3. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 8 (Black/Orange wire) at ECM electrical connector E2. This is the IGSW terminal at ECM. Voltage should be 9-14 volts. If voltage is not within specification, go to next step. If voltage is within specification, go to step 5.
4. Check ignition switch. See «IGNITION SWITCH»(ref-133221-S37155000612001121400000) under ENGINE SENSORS & SWITCHES. If ignition switch is defective, replace ignition switch. See «IGNITION SWITCH»(ref-133226-S01193468262002051300000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. If ignition switch is okay, check for open and short in wiring harness and electrical connectors between battery and ignition switch, and between ignition switch and terminal No. 8 (Black/Orange wire) at ECM electrical connector E2. See «WIRING DIAGRAMS»(ref-133228) article. If necessary to check AM2 fuse, AM2 fuse is located in fuse/relay box at driver's side front corner of engine compartment, just in front of strut tower. Repair wiring harness or electrical connectors as necessary.
5. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-133221-S21045574842002021900000) under MODULES, MOTORS, RELAYS & SOLENOIDS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
6. Check for defective EFI fuse. EFI fuse is located in fuse/relay box at driver's side front corner of engine compartment, just in front of strut tower. If EFI fuse is okay, go to next step. If EFI fuse is defective, repair short in wiring harness between battery and EFI fuse. See «WIRING DIAGRAMS»(ref-133228) article.
7. Check for defective EFI No. 1 fuse. EFI No. 1 fuse is located in fuse/relay box at driver's side front corner of engine compartment, just in front of strut tower. EFI No. 1 fuse may also be referred to as EFI1 fuse. If EFI No. 1 fuse is okay, go to next step. If EFI No. 1 fuse is defective, repair short in wiring harness and components connected to EFI No. 1 fuse. See «WIRING DIAGRAMS»(ref-133228) article.
8. Check for open and short in wiring harness and electrical connectors between terminal No. 21 (Blue/Black wire) at ECM electrical connector E3 and EFI main relay, and for open in White/Black wire between EFI main relay and body ground. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
9. Check wiring harness and electrical connectors between battery and EFI fuse, and between EFI No. 1 fuse and terminal No. 16 (Black/Red wire) at ECM electrical connector E2. Repair wiring harness or and electrical connectors as necessary.

Corolla

1. Remove necessary components for access to Engine Control Module (ECM). See «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
2. Remove bolts from ECM so electrical connectors can be accessed on ECM. Note ECM electrical connector terminals. (Scheme 140)and (Scheme 141).
3. Turn ignition on. On 3-speed A/T and M/T models, using voltmeter, check voltage between terminals No. 12 (Black wire) at ECM electrical connector E6 and No. 14 (Brown wire) at ECM electrical connector E4. On 4-speed A/T, using voltmeter, check voltage between terminals No. 16 (Black wire) at ECM electrical connector E10 and No. 17 (Brown wire) at ECM electrical connector E8. On all models, this is the +B and E1 terminals at ECM. Voltage should be 9-14 volts. If voltage is within specification, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article. If voltage is not within specification, check for open in wiring harness and electrical connectors between terminal No. 14 (Brown wire) at ECM electrical connector E4 and body ground on 3-speed A/T and M/T models, or terminal No. 17 (Brown wire) at ECM electrical connector E8 and body ground on 4-speed A/T models. See «WIRING DIAGRAMS»(ref-133228) article. On all models, if wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
4. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-133221-S21045574842002021900000) under MODULES, MOTORS, RELAYS & SOLENOIDS. EFI main relay may also be referred to as EFI relay or F-HTR relay. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
5. Check for defective EFI fuse. EFI fuse may also be referred to as F-HTR fuse. EFI fuse is located in fuse/relay box at driver's side front corner of engine compartment, just in front of strut tower. If EFI fuse is okay, go to next step. If EFI fuse is defective, repair short in wiring harness and components connected to EFI fuse. See «WIRING DIAGRAMS»(ref-133228) article.
6. Check for open in wiring harness and electrical connectors between EFI main relay and battery, and between EFI main relay and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
7. Check for defective IGN fuse. IGN fuse is located in fuse/relay box behind driver's side of instrument panel. If IGN fuse is okay, go to next step. If IGN fuse is defective, repair short in wiring harness and components connected to IGN fuse. See «WIRING DIAGRAMS»(ref-133228) article.
8. Check ignition switch. See «IGNITION SWITCH»(ref-133221-S37155000612001121400000) under ENGINE SENSORS & SWITCHES. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch. See «IGNITION SWITCH»(ref-133226-S01193468262002051300000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
9. Check for open in wiring harness and electrical connectors between ignition switch and EFI main relay, and between body ground and EFI main relay. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, test is complete. If wiring harness or electrical connector is defective, repair as necessary.

ECHO

1. Remove cover from Engine Control Module (ECM) for access to ECM electrical connectors. ECM is located behind glove box. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. Note ECM electrical connector terminals. (Scheme 142)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 12 (Black/Red wire) at ECM electrical connector E4 and No. 14 (Brown wire) at ECM electrical connector E7. This is the +B and E1 terminals at ECM. Voltage should be 9-14 volts. If voltage is within specification, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article. If voltage is not within specification, check for open in wiring harness and electrical connectors between terminal No. 14 (Brown wire) at ECM electrical connector E7 and body ground. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
3. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-133221-S21045574842002021900000) under MODULES, MOTORS, RELAYS & SOLENOIDS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
4. Check for defective EFI fuse. EFI fuse is located in fuse/relay box at driver's side front corner of engine compartment, just in front of strut tower, near battery. If EFI fuse is okay, go to next step. If EFI fuse is defective, repair short in wiring harness and components connected to EFI fuse. See «WIRING DIAGRAMS»(ref-133228) article.
5. Check for open in wiring harness and electrical connectors between EFI main relay and battery, and between EFI main relay and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
6. Check ignition switch. See «IGNITION SWITCH»(ref-133221-S37155000612001121400000) under ENGINE SENSORS & SWITCHES. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch. See «IGNITION SWITCH»(ref-133226-S01193468262002051300000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
7. Check for open in wiring harness and electrical connectors between ignition switch and EFI main relay, and between body ground and EFI main relay. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, test is complete. If wiring harness or electrical connector is defective, repair as necessary.

Highlander

1. Remove glove box for access to Engine Control Module (ECM). For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. Note ECM electrical connector terminals. (Scheme 143)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 16 (White wire) at ECM electrical connector E5 and No. 17 (Brown wire) at ECM electrical connector E8. This is the +B and E1 terminals at ECM. Voltage should be 9-14 volts. If voltage is not within specification, go to next step. If voltage is within specification, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
3. Turn ignition off. Disconnect electrical connector E8 from ECM. Using ohmmeter, check for continuity between body ground and terminal No. 17 (Brown wire) at ECM electrical connector E8. If continuity exists, reinstall electrical connector E8 at ECM and go to next step. If continuity does not exist, repair open in Brown wire between terminal No. 17 at ECM electrical connector E8 and body ground. See «WIRING DIAGRAMS»(ref-133228) article.
4. Ensure ignition is off. Check for open and short in White wire between EFI main relay and terminal No. 16 at ECM electrical connector E5. See «WIRING DIAGRAMS»(ref-133228) article. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment, just in front of strut tower. If wiring is okay, go to next step. If wiring is defective, repair as necessary.
5. Turn ignition on. Using voltmeter, check voltage between terminals No. 2 (Black/Orange wire) at ECM electrical connector E5 and No. 17 (Brown wire) at ECM electrical connector E8. This is the IGSW and E1 terminals at ECM. Voltage should be 9-14 volts. If voltage is not within specification, go to next step. If voltage is within specification, go to step 10.
6. Check for defective IGN fuse. IGN fuse is located in fuse box behind driver's side of instrument panel. If IGN fuse is okay, go to next step. If IGN fuse is defective, repair short in wiring harness and components connected to IGN fuse. See «WIRING DIAGRAMS»(ref-133228) article.
7. Check for defective AM2 fuse. AM2 fuse is located in fuse/relay box at driver's side front corner of engine compartment, just in front of strut tower. If AM2 fuse is okay, go to next step. If AM2 fuse is defective, repair short in wiring harness and components connected to AM2 fuse. See «WIRING DIAGRAMS»(ref-133228) article.
8. Check ignition switch. See «IGNITION SWITCH»(ref-133221-S37155000612001121400000) under ENGINE SENSORS & SWITCHES. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch. See «IGNITION SWITCH»(ref-133226-S01193468262002051300000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
9. Check for open in wiring harness and electrical connectors between battery and ignition switch, and between ignition switch and terminal No. 2 (Black/Orange wire) at ECM electrical connector E5. See «WIRING DIAGRAMS»(ref-133228) article. Repair wiring harness or electrical connectors as necessary.
10. Ensure ignition is on. Using voltmeter, check voltage between terminals No. 8 (Pink/Blue wire) at ECM electrical connector E5 and No. 17 (Brown wire) at ECM electrical connector E8. This is the MREL and E1 terminals at ECM. Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. On models equipped with engine immobilizer system, if ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.
11. Check for defective EFI fuse. EFI fuse is located in fuse/relay box at driver's side front corner of engine compartment, just in front of strut tower. If EFI fuse is okay, go to next step. If EFI fuse is defective, repair short in wiring harness and components connected to EFI fuse. See «WIRING DIAGRAMS»(ref-133228) article.
12. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-133221-S21045574842002021900000) under MODULES, MOTORS, RELAYS & SOLENOIDS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
13. Check for open and short in wiring harness and electrical connectors between terminal No. 8 (Pink/Blue wire) at ECM electrical connector E5 and EFI main relay, and for open in White/Black wire between EFI main relay and body ground. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
14. Check wiring harness and electrical connectors between battery and EFI fuse. See «WIRING DIAGRAMS»(ref-133228) article. Repair wiring harness or and electrical connectors as necessary.

MR2

1. Remove necessary components for access to Engine Control Module (ECM). ECM is located on inside of firewall, directly behind driver's seat and luggage compartment. See «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
2. Remove bolts and disconnect ECM with electrical connectors from inside of firewall. Note ECM electrical connector terminals. (Scheme 144)
3. Turn ignition on. Using voltmeter, check voltage between terminals No. 16 (Black wire) at ECM electrical connector E2 and No. 17 (Brown wire) at ECM electrical connector E4. This is the +B and E1 terminals at ECM. Voltage should be 9-14 volts. If voltage is within specification, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article. If voltage is not within specification, check for open in wiring harness and electrical connectors between terminal No. 17 (Brown wire) at ECM electrical connector E4 and body ground. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
4. Turn ignition off. Check for open and short in Black wire between EFI main relay and terminal No. 16 at ECM electrical connector E2. See «WIRING DIAGRAMS»(ref-133228) article. EFI main relay is located in relay box on firewall at driver's side front corner of engine compartment. If wiring is okay, go to next step. If wiring is defective, repair as necessary.
5. Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 8 (Black/Red wire) at ECM electrical connector E2. This is the IGSW terminal at ECM. Voltage should be 9-14 volts. If voltage is not within specification, go to next step. If voltage is within specification, go to step 11.
6. Check for defective IG2 fuse. IG2 fuse is located in fuse/relay box at driver's side rear corner of engine compartment, just in front of strut tower. If IG2 fuse is okay, go to next step. If IG2 fuse is defective, repair short in wiring harness and components connected to IGN fuse. See «WIRING DIAGRAMS»(ref-133228) article.
7. Check operation of IG2 relay. See «IG2 RELAY»(ref-133221-S31944374972002021900000) under MODULES, MOTORS, RELAYS & SOLENOIDS. If IG2 relay operates properly, go to next step. If IG2 relay is defective, replace IG2 relay.
8. Check for defective AM2 fuse. AM2 fuse is located in fuse/relay box at driver's side rear corner of engine compartment, just in front of strut tower. If AM2 fuse is okay, go to next step. If AM2 fuse is defective, repair short in wiring harness and components connected to AM2 fuse. See «WIRING DIAGRAMS»(ref-133228) article.
9. Check ignition switch. See «IGNITION SWITCH»(ref-133221-S37155000612001121400000) under ENGINE SENSORS & SWITCHES. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch. See «IGNITION SWITCH»(ref-133226-S01193468262002051300000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
10. Check for open in wiring harness and electrical connectors between battery and ignition switch, battery and IG2 relay, ignition switch and IG2 relay, and between IG2 relay and terminal No. 8 (Black/Red wire) at ECM electrical connector E2. See «WIRING DIAGRAMS»(ref-133228) article. Repair wiring harness or electrical connectors as necessary.
11. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 21 (Gray wire) at ECM electrical connector E3. This is the MREL terminal at ECM. Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. On models equipped with engine immobilizer system, if ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.
12. Check for defective EFI No. 1 fuse. EFI No. 1 fuse is located in fuse/relay box at driver's side rear corner of engine compartment, just in front of strut tower. EFI No. 1 fuse may also be referred to as EFI1 fuse. If EFI No. 1 fuse is okay, go to next step. If EFI No. 1 fuse is defective, repair short in wiring harness and components connected to EFI No. 1 fuse. See «WIRING DIAGRAMS»(ref-133228) article.
13. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-133221-S21045574842002021900000) under MODULES, MOTORS, RELAYS & SOLENOIDS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
14. Check for open and short in wiring harness and electrical connectors between terminal No. 21 (Gray wire) at ECM electrical connector E3 and EFI main relay, and for open in White/Black wire between EFI main relay and body ground. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
15. Check wiring harness and electrical connectors between battery and EFI No. 1 fuse, and between EFI No. 1 fuse and EFI main relay. See «WIRING DIAGRAMS»(ref-133228) article. Repair wiring harness or and electrical connectors as necessary.

1. Remove glove box for access to Engine Control Module (ECM). For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. Note ECM electrical connector terminals. (Scheme 145)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 4 (Black wire) at ECM electrical connector E8 and No. 17 (Brown wire) at ECM electrical connector E8. This is the +B and E1 terminals at ECM. Voltage should be 9-14 volts. If voltage is within specification, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article. If voltage is not within specification, check for open in wiring harness and electrical connectors between terminal No. 17 (Brown wire) at ECM electrical connector E8 and body ground. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
3. Turn ignition off. Check for open and short in Black wire between EFI main relay and terminal No. 4 at ECM electrical connector E8. See «WIRING DIAGRAMS»(ref-133228) article. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment, just in front of strut tower. If wiring is okay, go to next step. If wiring is defective, repair as necessary.
4. Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 9 (Black/White wire) at ECM electrical connector E10. This is the IGSW terminal at ECM. Voltage should be 9-14 volts. If voltage is not within specification, go to next step. If voltage is within specification, go to step 8.
5. Check for defective AM2 fuse. AM2 fuse is located in fuse/relay box at driver's side front corner of engine compartment. If AM2 fuse is okay, go to next step. If AM2 fuse is defective, repair short in wiring harness and components connected to AM2 fuse. See «WIRING DIAGRAMS»(ref-133228) article.
6. Check ignition switch. See «IGNITION SWITCH»(ref-133221-S37155000612001121400000) under ENGINE SENSORS & SWITCHES. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch. See «IGNITION SWITCH»(ref-133226-S01193468262002051300000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
7. Check for open in wiring harness and electrical connectors between battery and ignition switch and between ignition switch and terminal No. 9 (Black/White wire) at ECM electrical connector E10. See «WIRING DIAGRAMS»(ref-133228) article. Repair wiring harness or electrical connectors as necessary.
8. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 25 (Green/Red wire) at ECM electrical connector E9. This is the MREL terminal at ECM. Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.
9. Check for defective EFI fuse. EFI fuse is located in fuse/relay box at driver's side front corner of engine compartment. If EFI fuse is okay, go to next step. If EFI fuse is defective, repair short in wiring harness and components connected to EFI fuse. See «WIRING DIAGRAMS»(ref-133228) article.
10. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-133221-S21045574842002021900000) under MODULES, MOTORS, RELAYS & SOLENOIDS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
11. Check for open and short in wiring harness and electrical connectors between terminal No. 25 (Green/Red wire) at ECM electrical connector E9 and EFI main relay, and for open in White/Black wire between EFI main relay and body ground. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
12. Check wiring harness and electrical connectors between battery and EFI fuse, and between EFI fuse and EFI main relay. See «WIRING DIAGRAMS»(ref-133228) article. Repair wiring harness or and electrical connectors as necessary.

1. Remove glove box for access to Engine Control Module (ECM). ECM is located near passenger's side kick panel, just below instrument panel. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. Note ECM electrical connector terminals. (Scheme 146)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 16 (Black/Red or Light Green wire) at ECM electrical connector E8 and No. 17 (Brown wire) at ECM electrical connector E5. There are 2 different wiring harnesses used. Wire color at terminal No. 16 may vary according to wiring harness used. This is the +B and E1 terminals at ECM. Voltage should be 9-14 volts. If voltage is within specification, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article. If voltage is not within specification, check for open in wiring harness and electrical connectors between terminal No. 17 (Brown wire) at ECM electrical connector E5 and body ground. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
3. Turn ignition off. Check for open and short in Black/Red or Light Green wire between EFI main relay and terminal No. 16 at ECM electrical connector E8. See «WIRING DIAGRAMS»(ref-133228) article. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment, just in front of strut tower. If wiring is okay, go to next step. If wiring is defective, repair as necessary.
4. Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 2 (Black/Orange or White wire) at ECM electrical connector E8. This is the IGSW terminal at ECM. Voltage should be 9-14 volts. If voltage is not within specification, go to next step. If voltage is within specification, go to step 9.
5. Check for defective IG2 fuse. IG2 fuse is located in fuse box behind driver's side of instrument panel. If IG2 fuse is okay, go to next step. If IG2 fuse is defective, repair short in wiring harness and components connected to IG2 fuse. See «WIRING DIAGRAMS»(ref-133228) article.
6. Check for defective AM2 fuse. AM2 fuse is located in fuse/relay box at driver's side front corner of engine compartment. If AM2 fuse is okay, go to next step. If AM2 fuse is defective, repair short in wiring harness and components connected to AM2 fuse. See «WIRING DIAGRAMS»(ref-133228) article.
7. Check ignition switch. See «IGNITION SWITCH»(ref-133221-S37155000612001121400000) under ENGINE SENSORS & SWITCHES. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch. See «IGNITION SWITCH»(ref-133226-S01193468262002051300000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
8. Check for open in wiring harness and electrical connectors between battery and ignition switch, and between ignition switch and terminal No. 2 (Black/Orange or White wire) at ECM electrical connector E8. See «WIRING DIAGRAMS»(ref-133228) article. Repair wiring harness or electrical connectors as necessary.
9. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 8 (Green/White or White wire) at ECM electrical connector E8. This is the MREL terminal at ECM. Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. On models equipped with engine immobilizer system, if ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.
10. Check for defective EFI No. 1 fuse. EFI No. 1 fuse is located in fuse/relay box at driver's side front corner of engine compartment. EFI No. 1 fuse may also be referred to as EFI1 fuse. If EFI No. 1 fuse is okay, go to next step. If EFI No. 1 fuse is defective, repair short in wiring harness and components connected to EFI No. 1 fuse. See «WIRING DIAGRAMS»(ref-133228) article.
11. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-133221-S21045574842002021900000) under MODULES, MOTORS, RELAYS & SOLENOIDS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
12. Check for open in wiring harness and electrical connectors between EFI main relay, EFI No. 1 fuse and battery. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
13. Check for open and short in wiring harness and electrical connectors between terminal No. 8 (Green/White or White wire) at ECM electrical connector E8 and EFI main relay, and for open in White/Black wire between EFI main relay and body ground. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, test is complete. If wiring harness or electrical connector is defective, repair as necessary.

Tacoma

1. Remove glove box for access to ECM. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. Note ECM electrical connector terminals. (Scheme 147)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 16 (White/Red wire) at ECM electrical connector E5 and No. 17 (Brown wire) at ECM electrical connector E7. This is the +B and E1 terminals at ECM. Voltage should be 9-14 volts. If voltage is within specification, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article. If voltage is not within specification, check for open in wiring harness and electrical connectors between terminal No. 17 (Brown wire) at ECM electrical connector E7 and body ground. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
3. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-133221-S21045574842002021900000) under MODULES, MOTORS, RELAYS & SOLENOIDS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
4. Check for defective EFI fuse. EFI fuse is located in fuse/relay box at driver's side front corner of engine compartment, next to battery. If EFI fuse is okay, go to next step. If EFI fuse is defective, repair short in wiring harness and components connected to EFI fuse. See «WIRING DIAGRAMS»(ref-133228) article.
5. Check for open in wiring harness and electrical connectors between EFI main relay and battery, and between EFI main relay and terminals No. 16 (White/Red wire) at ECM electrical connector E5. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
6. Check for defective IGN fuse. IGN fuse is located in fuse/relay box behind driver's side of instrument panel. If IGN fuse is okay, go to next step. If IGN fuse is defective, repair short in wiring harness and components connected to IGN fuse. See «WIRING DIAGRAMS»(ref-133228) article.
7. Check ignition switch. See «IGNITION SWITCH»(ref-133221-S37155000612001121400000) under ENGINE SENSORS & SWITCHES. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch. See «IGNITION SWITCH»(ref-133226-S01193468262002051300000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
8. Check for open in wiring harness and electrical connectors between ignition switch and EFI main relay, and for open in White/Black wire between EFI main relay and body ground. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, test is complete. If wiring harness or electrical connector is defective, repair as necessary.

FUEL PUMP CONTROL CIRCUIT

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

1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step 3.
2. Check operation of fuel pump by using Toyota hand-held tester. See «FUEL PUMP OPERATION»(ref-133196-S33506992762002021900000) under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If fuel pump does not operate when using hand-held tester, go to step 5. If fuel pump operates when using hand-held tester, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
3. Remove necessary components for access to Engine Control Module (ECM). See «ENGINE CONTROL MODULE LOCATION»(ref-133221-S07930508892002021900000) table.
4. Note ECM terminals. (Scheme 137)- (Scheme 147). Turn ignition on. Momentarily connect jumper wire between body ground and FC terminal at ECM and listen for fuel pump operating sound. See «ECM IDENTIFICATION FOR FUEL PUMP FC TERMINAL»(ref-133221-S23500210242002021900000) table. On Camry, Celica, Corolla, ECHO, Highlander, MR2, Prius and RAV4, feel for fuel pressure in fuel inlet line at end of fuel rail when fuel inlet line is pinched closed. On Camry Solara, feel for fuel pressure in fuel inlet line at fuel filter when fuel inlet line is pinched closed. On Tacoma, feel for fuel pressure in fuel return line from fuel pressure regulator when fuel return line is pinched closed. On all models, if fuel pump does not operate when jumper wire was connected, go to next step. If fuel pump operates when jumper wire was connected, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
5. Check ECM power source circuit. See «ENGINE CONTROL MODULE POWER SOURCE CIRCUIT»(ref-133221-S10558774742002021900000). If ECM power source circuit is okay, go to next step. If ECM power source circuit is defective, repair as necessary.
6. Check circuit opening relay. See «CIRCUIT OPENING RELAY»(ref-133221-S15425192882002021900000) under MODULES, MOTORS, RELAYS & SOLENOIDS. If circuit opening relay is okay, go to next step. If circuit opening relay is defective, replace circuit opening relay.
7. Remove necessary components for access to ECM if not previously done. See «ENGINE CONTROL MODULE LOCATION»(ref-133221-S07930508892002021900000) table. ENGINE CONTROL MODULE LOCATION Model (1) Location Camry & Camry Solara Behind Glove Box Celica In Engine Compartment, Below Cover, Just In Front Of Battery, Next To Driver's Side Strut Tower Corolla Behind Stereo On Instrument Panel, Just In Front Of Center Console ECHO & Highlander Behind Glove Box MR2 On Inside Of Firewall, Directly Behind Driver's Seat & Luggage Compartment Prius Behind Glove Box RAV4 Near Passenger's Side Kick Panel, Just Below Instrument Panel Tacoma Behind Glove Box (1) For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article.
8. Note ECM terminals. (Scheme 137)- (Scheme 147). Turn ignition on. Using voltmeter, check voltage between body ground and FC terminal at ECM. See «ECM IDENTIFICATION FOR FUEL PUMP FC TERMINAL»(ref-133221-S23500210242002021900000) table. ECM IDENTIFICATION FOR FUEL PUMP FC TERMINAL Application ECM Connector ECM Terminal No. (Wire Color) Camry E6 10 (Green/Red) Camry Solara E7 10 (Green/Red) Celica E2 3 (Green/Red) Corolla 3-Speed A/T & M/T E6 14 (Green/Red) 4-Speed A/T E10 3 (Green/Red) ECHO E4 14 (Green) Highlander E5 3 (Green/Red) MR2 E2 3 (Green/Red) Prius E8 9 (Green/Red) RAV4 E8 (1) 3 (Green/Red Or White) Tacoma E6 6 (White/Blue) (1) There are 2 different wiring harnesses used. Wire color at designated terminal may vary according to wiring harness used.
9. Voltage should be 9-14 volts. If voltage is within specification, go to next step. On Camry, Camry Solara, Highlander, MR2, RAV4 and Tacoma, if voltage is not within specification, check for open in wiring harness and connectors between ECM and circuit opening relay, and between ignition switch and circuit opening relay. See «WIRING DIAGRAMS»(ref-133228) article. On Celica, Corolla, ECHO and Prius, if voltage is not within specification, check for open in wiring harness and connectors between ECM and circuit opening relay, and between EFI main relay and circuit opening relay. See «WIRING DIAGRAMS»(ref-133228) article. For EFI main relay location, see «EFI MAIN RELAY»(ref-133221-S21045574842002021900000) under MODULES, MOTORS, RELAYS & SOLENOIDS. On all models, if wiring harness or electrical connector is defective, repair as necessary.
10. Check fuel pump resistance and operation. See «FUEL DELIVERY»(ref-133221-S17025239702002021900000) under FUEL SYSTEMS. If fuel pump resistance is within specification and fuel pump operates, go to next step. If fuel pump resistance is not within specification or fuel pump does not operate, replace fuel pump. See «FUEL PUMP»(ref-133226-S07700574872002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
11. Check for open in wiring harness and electrical connectors between circuit opening relay and fuel pump, and between fuel pump and body ground. See «WIRING DIAGRAMS»(ref-133228) article. On Camry, Camry Solara, Highlander, MR2, RAV4 and Tacoma, also check for open in wiring harness and electrical connectors between circuit opening relay and EFI main relay. See «WIRING DIAGRAMS»(ref-133228) article. For EFI main relay location, see «EFI MAIN RELAY»(ref-133221-S21045574842002021900000) under MODULES, MOTORS, RELAYS & SOLENOIDS. On all models, if wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
12. Check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. On Camry, Camry Solara, Highlander, MR2 and RAV4, if ECM is replaced and vehicle is equipped with engine immobilizer system, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

STARTER 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 TROUBLE SHOOTING - NO CODES article.

Note. When performing starter signal circuit test, it may be necessary to consult the starter wiring diagram for the entire wiring circuit. For starter wiring diagram, see WIRING DIAGRAMS in appropriate STARTERS article in STARTING & CHARGING SYSTEMS.

Camry & Camry Solara

1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step 5.
2. Connect hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 127)and (Scheme 128). Turn ignition on and then turn hand-held tester on. Read STA signal display on hand-held tester with ignition on, and with ignition switch in START position and engine cranking. STA signal display should read OFF with ignition on, and ON with ignition switch in START position. If STA signal display is not as specified, go to next step. If STA signal display is as specified, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
3. Check for open in Black/White wire (Camry) or Gray wire (Camry Solara) and electrical connectors between STA terminal at Engine Control Module (ECM) and park/neutral position switch (A/T) or clutch start switch (M/T). See «WIRING DIAGRAMS»(ref-133228) article. Park/neutral position switch is located on side of transaxle and clutch start switch is located near top of clutch pedal. See «ECM TERMINAL IDENTIFICATION FOR STARTER SIGNAL (CAMRY & CAMRY SOLARA)»(ref-133221-S14069479772002021900000) table. ECM is located behind glove box. For illustration of ECM location, see THEORY & OPERATION article. For ECM electrical connector terminal identification (Scheme 137)and (Scheme 138).
4. If wiring harness or electrical connector is defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. On models equipped with engine immobilizer system, if ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.
5. Remove glove box for access to Engine Control Module (ECM). For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. Note ECM electrical connector terminals. (Scheme 137)and (Scheme 138). Using voltmeter, check voltage between body ground and STA terminal (starter signal wire) at ECM with ignition switch in START position and engine cranking. See «ECM TERMINAL IDENTIFICATION FOR STARTER SIGNAL (CAMRY & CAMRY SOLARA)»(ref-133221-S14069479772002021900000) table. ECM TERMINAL IDENTIFICATION FOR STARTER SIGNAL (CAMRY & CAMRY SOLARA) Application ECM Connector ECM Terminal No. (Wire Color) Camry E9 9 (Black/White) Camry Solara E10 9 (Gray)
6. Voltage should be 6 volts or more. If voltage is not within specification, go to next step. If voltage is within specification, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
7. Check for open in Black/White wire (Camry) or Gray wire (Camry Solara) and electrical connectors between STA terminal at ECM and park/neutral position switch (A/T) or clutch start switch (M/T). See «WIRING DIAGRAMS»(ref-133228) article. Park/neutral position switch is located on side of transaxle and clutch start switch is located near top of clutch pedal. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary. If ECM ground circuit is okay, replace ECM. On models equipped with engine immobilizer system, if ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

Celica & ECHO

Testing information is not available from manufacturer.

1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step 5.
2. Connect hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 130) Turn ignition on and then turn hand-held tester on. Read STA signal display on hand-held tester with ignition on, and with ignition switch in START position and engine cranking. STA signal display should read OFF with ignition on, and ON with ignition switch in START position. If STA signal display is not as specified, go to next step. If STA signal display is as specified, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
3. Check for open in Black/White wire (starter signal wire) and electrical connectors between starter relay and terminal No. 11 at Engine Control Module (ECM) electrical connector E6 on 3-speed A/T and M/T models, or terminal No. 11 at ECM electrical connector E9 on 4-speed A/T models. See «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind stereo on instrument panel, just in front of center console. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. Starter relay is located in fuse/relay box at driver's side front corner of engine compartment, just in front of strut tower and may be marked as ST relay. For ECM electrical connector terminal identification (Scheme 140)and (Scheme 141).
4. If wiring harness or electrical connector is defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.
5. Remove necessary components for access to Engine Control Module (ECM). See «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Remove bolts from ECM so electrical connectors can be accessed on ECM.
6. Note ECM electrical connector terminals. (Scheme 140)and (Scheme 141). On 3-speed A/T and M/T models, using voltmeter, check voltage between body ground and terminal No. 11 (Black/White wire) at ECM electrical connector E6 with ignition switch in START position and engine cranking. On 4-speed A/T models, using voltmeter, check voltage between body ground and terminal No. 11 (Black/White wire) at ECM electrical connector E9 with ignition switch in START position and engine cranking. On all models, this is the STA terminal at ECM.
7. On all models, voltage should be 6 volts or more. If voltage is not within specification, go to next step. If voltage is within specification, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
8. Check for open and short in Black/White wire and electrical connectors between starter relay and terminal No. 11 at ECM electrical connector E6 on 3-speed A/T and M/T models, or terminal No. 11 at ECM electrical connector E9 on 4-speed A/T models. See «WIRING DIAGRAMS»(ref-133228) article. This is the starter signal wire. Starter relay is located in fuse/relay box at driver's side front corner of engine compartment, just in front of strut tower and may be marked as ST relay.
9. If wiring harness or electrical connector is defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.

1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step 5.
2. Connect hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 132) Turn ignition on and then turn hand-held tester on. Read STA signal display on hand-held tester with ignition on, and with ignition switch in START position and engine cranking. STA signal display should read OFF with ignition on, and ON with ignition switch in START position. If STA signal display is not as specified, go to next step. If STA signal display is as specified, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
3. Check for open and short in White/Red wire between starter relay and starter fuse, defective starter fuse, and for open and short in Blue wire and electrical connectors between starter fuse and terminal No. 16 at Engine Control Module (ECM) electrical connector E7. This is the starter signal circuit between starter relay and ECM. See «WIRING DIAGRAMS»(ref-133228) article. Starter relay and starter fuse are located in fuse/relay box at driver's side front corner of engine compartment, just in front of strut tower. ECM is located behind glove box. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. For ECM electrical connector terminal identification (Scheme 143)
4. If starter fuse, wiring harness or electrical connector is defective, replace fuse or repair wiring harness or electrical connector as necessary. If starter fuse, wiring harness and electrical connectors are okay, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. On models equipped with engine immobilizer system, if ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.
5. Remove glove box for access to Engine Control Module (ECM). For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article.
6. Note ECM electrical connector terminals. (Scheme 143) Using voltmeter, check voltage between body ground and terminal No. 16 (Blue wire) at ECM electrical connector E7 with ignition switch in START position and engine cranking. (Scheme 143) This is the STA terminal at ECM. Voltage should be 6 volts or more. If voltage is not within specification, go to next step. If voltage is within specification, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
7. Check for open and short in White/Red wire between starter relay and starter fuse, defective starter fuse, and for open and short in Blue wire and electrical connectors between starter fuse and terminal No. 16 at ECM electrical connector E7. This is the starter signal circuit between starter relay and ECM. See «WIRING DIAGRAMS»(ref-133228) article. Starter relay and starter fuse are located in fuse/relay box at driver's side front corner of engine compartment, just in front of strut tower.
8. If starter fuse, wiring harness or electrical connector is defective, replace fuse or repair wiring harness or electrical connector as necessary. If starter fuse, wiring harness and electrical connectors are okay, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. On models equipped with engine immobilizer system, if ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step 5.
2. Connect hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 133) Turn ignition on and then turn hand-held tester on. Read STA signal display on hand-held tester with ignition on, and with ignition switch in START position and engine cranking. STA signal display should read OFF with ignition on, and ON with ignition switch in START position. If STA signal display is not as specified, go to next step. If STA signal display is as specified, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
3. Check for open and short in Black wire between starter relay and starter fuse, defective starter fuse, and for open and short in Black wire and electrical connectors between starter fuse and terminal No. 11 at Engine Control Module (ECM) electrical connector E3. This is the starter signal circuit between starter relay and ECM. See «WIRING DIAGRAMS»(ref-133228) article. Starter relay and starter fuse are located in fuse/relay box at driver's side rear corner of engine compartment, just in front of strut tower and may be marked as ST relay and ST fuse. ECM is located on inside of firewall, directly behind driver's seat and luggage compartment. For illustration of ECM location, see THEORY & OPERATION article. To remove components for access to ECM, see «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. For ECM electrical connector terminal identification (Scheme 144)
4. If starter fuse, wiring harness or electrical connector is defective, replace fuse or repair wiring harness or electrical connector as necessary. If starter fuse, wiring harness and electrical connectors are okay, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. On models equipped with engine immobilizer system, if ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.
5. Remove necessary components for access to Engine Control Module (ECM). ECM is located on inside of firewall, directly behind driver's seat and luggage compartment. See «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Remove bolts and disconnect ECM with electrical connectors from inside of firewall.
6. Note ECM electrical connector terminals. (Scheme 144) Using voltmeter, check voltage between body ground and terminal No. 11 (Black wire) at ECM electrical connector E3 with ignition switch in START position and engine cranking. This is the STA terminal at ECM. Voltage should be 6 volts or more. If voltage is not within specification, go to next step. If voltage is within specification, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
7. Check for open and short in Black wire between starter relay and starter fuse, defective starter fuse, and for open and short in Black wire and electrical connectors between starter relay and terminal No. 11 at ECM electrical connector E3. This is the starter signal circuit between starter relay and ECM. See «WIRING DIAGRAMS»(ref-133228) article. Starter relay and starter fuse are located in fuse/relay box at driver's side rear corner of engine compartment, just in front of strut tower and may be marked as ST relay and ST fuse.
8. If starter fuse, wiring harness or electrical connector is defective, replace fuse or repair wiring harness or electrical connector as necessary. If starter fuse, wiring harness and electrical connectors are okay, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. On models equipped with engine immobilizer system, if ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

Testing information is not available from manufacturer.

1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step 5.
2. Connect hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 135) Turn ignition on and then turn hand-held tester on. Read STA signal display on hand-held tester with ignition on, and with ignition switch in START position and engine cranking. STA signal display should read OFF with ignition on, and ON with ignition switch in START position. If STA signal display is not as specified, go to next step. If STA signal display is as specified, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
3. Check for open and short in Black/White wire between starter relay and starter fuse, defective starter fuse, and for open and short in Black/Red or White wire and electrical connectors between starter fuse and terminal No. 7 (Black/Red or White wire) at Engine Control Module (ECM) electrical connector E8. There are 2 different wiring harnesses used. Wire color at between starter fuse and terminal No. 7 at ECM may vary according to wiring harness used. This is the starter signal circuit between starter relay and ECM. See «WIRING DIAGRAMS»(ref-133228) article. Starter relay and starter fuse are located in fuse/relay box at driver's side front corner of engine compartment and may be marked as ST relay and ST fuse. ECM is located near passenger's side kick panel, just below instrument panel. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. For ECM electrical connector terminal identification (Scheme 146)
4. If starter fuse, wiring harness or electrical connector is defective, replace fuse or repair wiring harness or electrical connector as necessary. If starter fuse, wiring harness and electrical connectors are okay, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. On models equipped with engine immobilizer system, if ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.
5. Remove glove box for access to Engine Control Module (ECM). For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article.
6. Note ECM electrical connector terminals (Scheme 146) Using voltmeter, check voltage between body ground and terminal No. 7 (Black/Red or White wire) at ECM electrical connector E8 with ignition switch in START position and engine cranking. There are 2 different wiring harnesses used. Wire color at terminal No. 7 at ECM may vary according to wiring harness used. This is the STA terminal at ECM. Voltage should be 6 volts or more. If voltage is not within specification, go to next step. If voltage is within specification, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
7. Check for open and short in Black/White wire between starter relay and starter fuse, defective starter fuse, and for open and short in Black/Red or White wire and electrical connectors between starter fuse and terminal No. 7 at ECM electrical connector E8. This is the starter signal circuit between starter relay and ECM. See «WIRING DIAGRAMS»(ref-133228) article. Starter relay and starter fuse are located in fuse/relay box at driver's side front corner of engine compartment and may be marked as ST relay and ST fuse.
8. If starter fuse, wiring harness or electrical connector is defective, replace fuse or repair wiring harness or electrical connector as necessary. If starter fuse, wiring harness and electrical connectors are okay, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. On models equipped with engine immobilizer system, if ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step 5.
2. Connect hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 136) Turn ignition on and then turn hand-held tester on. Read STA signal display on hand-held tester with ignition on, and with ignition switch in START position and engine cranking. STA signal display should read OFF with ignition on, and ON with ignition switch in START position. If STA signal display is not as specified, go to next step. If STA signal display is as specified, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
3. Check for open in Black/White wire between park/neutral position switch (A/T) or clutch start switch (M/T) and terminal No. 7 at Engine Control Module (ECM) electrical connector E5. This is the starter signal circuit to ECM. See «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind glove box. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. For ECM electrical connector terminal identification (Scheme 147) Park/neutral position switch is located on side of transmission and clutch start switch is located near top of clutch pedal.
4. If wiring harness or electrical connector is defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.
5. Remove glove box for access to Engine Control Module (ECM). For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article.
6. Note ECM electrical connector terminals. (Scheme 147) Using voltmeter, check voltage body ground and terminal No. 7 (Black/White wire) at ECM electrical connector E5 with ignition switch in START position and engine cranking. This is the STA terminal at ECM. Voltage should be 6 volts or more. If voltage is not within specification, go to next step. If voltage is within specification, diagnose by symptom. See «TROUBLE SHOOTING - NO CODES»(ref-133220) article.
7. Check for open in Black/White wire between park/neutral position switch (A/T) or clutch start switch (M/T) and terminal No. 7 at ECM electrical connector E5. This is the starter signal circuit to ECM. See «WIRING DIAGRAMS»(ref-133228) article. Park/neutral position switch is located on side of transmission and clutch start switch is located near top of clutch pedal.
8. If wiring harness or electrical connector is defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.

Scheme 127

Scheme 128

Scheme 129

Scheme 130

Scheme 131

Scheme 132

Scheme 133

Scheme 134

Scheme 135

Scheme 136

Power & Ground Circuits

For testing of Engine Control Module (ECM) power and ground circuits, see ENGINE CONTROL MODULE POWER SOURCE CIRCUIT. Also see PIN VOLTAGE CHARTS article. For illustration of ECM location, see THEORY & OPERATION article. For identification of ECM electrical connector terminals. (Scheme 137)- (Scheme 147).

Scheme 137

Scheme 138

Scheme 139

Scheme 140

Scheme 141

Scheme 142

Scheme 143

Scheme 144

Scheme 145

Scheme 146

Scheme 147

Scheme 148

1. Disconnect electrical connector at accelerator pedal position sensor. Accelerator pedal position sensor is located near top of accelerator pedal. (Scheme 148)
2. Using ohmmeter, check that resistance is within specification between specified terminals on accelerator pedal position sensor. See «ACCELERATOR PEDAL POSITION SENSOR RESISTANCE»(ref-133221-S28437197212002040500000) table. (Scheme 148) Replace accelerator pedal position sensor if resistance is not within specification. See «ACCELERATOR PEDAL POSITION SENSOR»(ref-133226-S32976509252002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. ACCELERATOR PEDAL POSITION SENSOR RESISTANCE Application Terminals Ohms Camry VPA1 & EP2 5000 Or Less VPA2 & EP1 5000 Or Less VCP1 & EP1 2250-4750 VCP2 & EP2 2250-4750 Camry Solara VCP1 & EP1 (1) 2250-4750 VCP2 & EP2 (1) 2250-4750 (1) Resistance at 68°F (20°C).

MR2 With Sequential Manual Transaxle

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

Scheme 149

1. Disconnect electrical connector at accelerator pedal position sensor. Accelerator pedal position sensor is located near top of accelerator pedal. (Scheme 149)
2. Using ohmmeter, check resistance between VCP1 and EP1 terminals, and between VCP2 and EP2 terminals on accelerator pedal position sensor. (Scheme 149) Resistance should be 1500-6000 ohms at 68°F (20°C). Replace accelerator pedal position sensor if resistance is not within specification. See «ACCELERATOR PEDAL POSITION SENSOR»(ref-133226-S32976509252002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

Scheme 150

Scheme 151

Scheme 152

Scheme 153

Scheme 154

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 150)- (Scheme 154). Ensure resistance is within specification. See «A/C COMPRESSOR LOCK SENSOR RESISTANCE»(ref-133221-S25404425542002032500000) 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

Scheme 155

1. Remove A/C evaporator temperature sensor. A/C evaporator temperature sensor is located in evaporator case, next to evaporator core. For servicing of A/C evaporator temperature sensor, see appropriate article in AIR CONDITIONING & HEATING.
2. Place probe end of A/C evaporator temperature sensor with thermometer in container of water. Using ohmmeter, check resistance between electrical terminals on A/C evaporator temperature sensor while using ice to cool water. Ensure ice does not contact A/C evaporator temperature sensor.
3. Check that resistance is within specification in relation to water temperature. (Scheme 155) Replace A/C evaporator temperature sensor if resistance is not within specification at specified temperature. For servicing of A/C evaporator temperature sensor, see appropriate article in AIR CONDITIONING & HEATING.

AIR/FUEL SENSOR

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

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 156) Replace A/F sensor if resistance is not within specification. See «A/F SENSOR HEATER RESISTANCE»(ref-133221-S29478009432002021900000) table. See «AIR/FUEL SENSOR»(ref-133226-S17977439112002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & 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 156) Replace A/F sensor if continuity exists. See «AIR/FUEL SENSOR»(ref-133226-S17977439112002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 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 157) Replace A/F sensor if resistance is not within specification. See «A/F SENSOR HEATER RESISTANCE»(ref-133221-S29478009432002021900000) table. See «AIR/FUEL SENSOR»(ref-133226-S17977439112002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

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 158)and (Scheme 159). Replace A/F sensor if resistance is not within specification. See «A/F SENSOR HEATER RESISTANCE»(ref-133221-S29478009432002021900000) table. See «AIR/FUEL SENSOR»(ref-133226-S17977439112002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

Scheme 156

Scheme 157

Scheme 158

Scheme 159

Scheme 160

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 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 160) Replace A/F sensor if resistance is not within specification. See «A/F SENSOR HEATER RESISTANCE»(ref-133221-S29478009432002021900000) table. See «AIR/FUEL SENSOR»(ref-133226-S17977439112002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. A/F SENSOR HEATER RESISTANCE Application & Temperature Ohms Camry 68°F (20°C) 1.8-3.4 932°F (500°C) 5.0-7.5 Camry Solara 68°F (20°C).8-1.4 Highlander 68°F (20°C) 1.8-3.4 932°F (500°C) 5.0-7.5 RAV4 68°F (20°C).8-1.4 1472°F (800°C) 1.8-3.2 Tacoma 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-133226-S15443530482002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
2. Using ohmmeter, check resistance between terminals E2 and THA on airflow meter. (Scheme 161)- (Scheme 164). Resistance should be within specification in relation to temperature. See «AIRFLOW METER RESISTANCE»(ref-133221-S38512445802002021900000) 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 & ECHO -4°F (-20°C) 13,600-18,400 68°F (20°C) 2210-2690 140°F (60°C) 490-670 Corolla -4°F (-20°C) 13,600-18,400 68°F (20°C) 2200-2700 140°F (60°C) 500-700 Highlander -4°F (-20°C) 13,600-18,400 68°F (20°C) 2210-2690 140°F (60°C) 493-667 MR2, 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
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 161) Connect voltmeter leads to proper terminals on airflow meter. (Scheme 161) Apply air into designated area on airflow meter and note voltage reading. (Scheme 161) 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 165)- (Scheme 167). Turn ignition on. Apply air into designated area on airflow meter and note voltage reading. (Scheme 161)and (Scheme 165) - (Scheme 167). While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate. Turn ignition off. Remove voltmeter.

Scheme 161

Scheme 162

Scheme 163

Scheme 164

Scheme 165

Scheme 166

Scheme 167

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 168)
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-133226-S38781797152002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

Scheme 168

Celica, Corolla, 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 169)
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-133226-S38781797152002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & 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-133226-S38781797152002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

Scheme 169

1. Disconnect electrical connector at brakelight switch. Brakelight switch is located near top of brake pedal. Note terminal identification on brakelight switch. (Scheme 170)
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-133226-S38781797152002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

Scheme 170

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.

Tacoma 2.7L 3RZ-FE

1. EGR gas temperature sensor is located near EGR valve. Remove EGR gas temperature sensor. See «EGR GAS TEMPERATURE SENSOR»(ref-133226-S03734989322002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
2. Place threaded end of EGR gas temperature sensor and thermometer in container of oil. Attach ohmmeter between electrical terminals on EGR gas temperature sensor.
3. Heat oil and note resistance at specified temperature. See «EGR GAS TEMPERATURE SENSOR RESISTANCE»(ref-133221-S11551722572002021900000) table. Replace EGR gas temperature sensor if resistance is not within specification. Reinstall EGR gas temperature sensor.

EGR GAS TEMPERATURE SENSOR RESISTANCE

Scheme 171

Scheme 172

Scheme 173

1. Ensure ignition is off. Disconnect electrical connector from Engine Coolant Temperature (ECT) sensor. See «ENGINE COOLANT TEMPERATURE SENSOR LOCATION»(ref-133221-S08125484322002021900000) table. Remove ECT sensor. See «ENGINE COOLANT TEMPERATURE SENSOR»(ref-133226-S40099607872002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
2. Place probe end of ECT sensor and thermometer in container of water. Attach ohmmeter between electrical terminals No. 1 and 2 on ECT sensor. (Scheme 171)and (Scheme 172). Heat water and note that resistance is within specification in relation to temperature. (Scheme 173) Replace ECT sensor if resistance is not within specification.

Highlander, MR2, Prius, RAV4 & Tacoma

1. Ensure ignition is off. Disconnect electrical connector from Engine Coolant Temperature (ECT) sensor. See «ENGINE COOLANT TEMPERATURE SENSOR LOCATION»(ref-133221-S08125484322002021900000) table. Remove ECT sensor. See «ENGINE COOLANT TEMPERATURE SENSOR»(ref-133226-S40099607872002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
2. Place probe end of ECT sensor and thermometer in container of water. Attach ohmmeter between electrical terminals on ECT sensor. Heat water and note that resistance is within specification in relation to temperature. (Scheme 173) Replace ECT sensor if resistance is not within specification. ENGINE COOLANT TEMPERATURE SENSOR LOCATION Model Location Camry & Camry Solara On Flywheel End Of Cylinder Head & Contains Dark Gray Electrical Connector With Green/Yellow & Brown Wires Celica On Flywheel End Of Cylinder Head & Contains Gray Electrical Connector With Green & Brown Wires Corolla On Flywheel End Of Cylinder Head & Contains Dark Gray Electrical Connector With White & Brown Wires ECHO On Flywheel End Of Cylinder Head & Contains Gray Electrical Connector With Red/Blue & Brown Wires 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 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 174

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-133221-S05995831792002021900000). 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 174) Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C). See «HEATED OXYGEN SENSOR»(ref-133227-S08172754992002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & 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 174) Replace heated oxygen sensor if continuity exists. See «HEATED OXYGEN SENSOR»(ref-133227-S08172754992002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & 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 175

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-133221-S05995831792002021900000). 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 175) Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C). See «HEATED OXYGEN SENSOR»(ref-133227-S08172754992002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & 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 176

Scheme 177

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 176) 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 177)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 176)and (Scheme 177). Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C). See «HEATED OXYGEN SENSOR»(ref-133227-S08172754992002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & 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 178) 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 179)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 178)and (Scheme 179). 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-133227-S08172754992002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & 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 178

Scheme 179

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 180) 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 181)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 180)and (Scheme 181). Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C). See «HEATED OXYGEN SENSOR»(ref-133227-S08172754992002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & 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 180

Scheme 181

Scheme 182

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-133221-S05995831792002021900000). 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 182) Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C). See «HEATED OXYGEN SENSOR»(ref-133227-S08172754992002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & 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 183)- (Scheme 185). Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 183)- (Scheme 185). 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-133227-S08172754992002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & 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 183

Scheme 184

Scheme 185

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 186) 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 187)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 186)and (Scheme 187). Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C). See «HEATED OXYGEN SENSOR»(ref-133227-S08172754992002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & 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 186

Scheme 187

Scheme 188

Scheme 189

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-133221-S05995831792002021900000). 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 188)and (Scheme 189). Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 188)and (Scheme 189). 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-133227-S08172754992002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & 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 190

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-133221-S05995831792002021900000). 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 190) 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-133227-S08172754992002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & 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 191

Scheme 192

Scheme 193

Scheme 194

1. Disconnect electrical connector from ignition switch on bottom of upper steering column bracket. (Scheme 191) Note ignition switch electrical terminals and ignition lock cylinder positions. (Scheme 192)- (Scheme 194).
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-133221-S35708655602001121400000) table. Replace ignition switch if defective. See «IGNITION SWITCH»(ref-133226-S01193468262002051300000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. IGNITION SWITCH CONTINUITY Application Ign. Lock Cylinder Position Ign. Switch Terminals Specification Camry, Camry Solara & Corolla, 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, 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, Camry Solara, Celica 1.8L 1ZZ-FE, Corolla, 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-133226-S04347412862002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
2. Using ohmmeter, check that no continuity exists between electrical terminal on knock sensor and body of knock sensor. Replace knock sensor if continuity exists.

Celica 1.8L 2ZZ-GE

1. Knock sensor is located on side of cylinder block. Manufacturer recommends removing knock sensor from cylinder block before testing. See «KNOCK SENSOR»(ref-133226-S04347412862002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
2. Using ohmmeter, check resistance between electrical terminals on knock sensor. Replace knock sensor if resistance is no 120,000-280,000 ohms at 68°F (20°C).

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 195)- (Scheme 198).
2. Using ohmmeter, check for continuity between specified terminals with shift lever in proper positions. See «PARK/NEUTRAL POSITION SWITCH SPECIFICATIONS»(ref-133221-S21965639512002021900000) 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-133226-S02246767272002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

PARK/NEUTRAL POSITION SWITCH SPECIFICATIONS

Scheme 195

Scheme 196

Scheme 197

Scheme 198

Scheme 199

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 199) 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-133221-S38847028892002021900000) 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

POWER STEERING PRESSURE SENSOR

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

Power steering pressure sensor is located on side of power steering pump. Testing information is not available from manufacturer. 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.

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.

1. Remove glove box for access to Engine Control Module (ECM). For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. Note ECM electrical connector terminals. (Scheme 143)
2. Start engine and allow engine to idle. Using voltmeter, check voltage between terminals No. 11 (Green/Yellow wire) at ECM electrical connector E7 and No. 17 (Brown wire) at ECM electrical connector E8. This is the PSW and E1 terminals at ECM. Check voltage with steering wheel at stationary position with engine idling, and while turning steering wheel with engine idling. Voltage should be 9-14 volts with steering wheel at stationary position and 0-3 volts while turning the steering wheel. If voltage is within specification, test is complete. If voltage is not within specification, go to next step.
3. Check wiring harness and electrical connectors between ECM and power steering pressure switch. See «WIRING DIAGRAMS»(ref-133228) article. Power steering pressure switch is located on power steering pump. If wiring harness or electrical connector is defective, repair as necessary. If wiring harness and electrical connectors are okay, replace power steering pressure switch. See «POWER STEERING PRESSURE SWITCH»(ref-133226-S04903895562002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

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

Celica, Corolla, ECHO, Highlander, RAV4 & Tacoma

1. Ensure ignition is off. Disconnect electrical connector from Throttle Position (TP) sensor on throttle body. Note terminal identification on TP sensor. (Scheme 200)- (Scheme 206).
2. On Tacoma, disconnect vacuum hose and apply vacuum to throttle opener. (Scheme 206) On all models, using ohmmeter, check resistance between specified terminals in relation to throttle position. See «THROTTLE POSITION SENSOR RESISTANCE»(ref-133221-S29143428822002021900000) table. Replace components as necessary if resistance is not within specification.

1. There are 2 types of throttle bodies and TP sensors used depending on type of transaxle used. On models with a standard type manual transaxle, the driver operates the clutch and shifts the transaxle. On models with sequential manual transaxle, the transaxle is electronically controlled and the clutch is operated and transaxle is shifted hydraulically by moving the shift lever forward or backward. 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 no clutch pedal is used.
2. For models with standard type manual transaxle, go to next step. For models with sequential manual transaxle, see «THROTTLE BODY»(ref-133221-S16414397892002021900000) under IDLE CONTROL SYSTEMS for testing of TP sensor.
3. Ensure ignition is off. Disconnect electrical connector from TP sensor on throttle body. Note terminal identification on TP sensor. (Scheme 204)
4. Using ohmmeter, check resistance between specified terminals in relation to throttle position. See «THROTTLE POSITION SENSOR RESISTANCE»(ref-133221-S29143428822002021900000) table. Replace components as necessary if resistance is not within specification.

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

THROTTLE POSITION SENSOR RESISTANCE

Scheme 200

Scheme 201

Scheme 202

Scheme 203

Scheme 204

Scheme 205

Scheme 206

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

Scheme 207

Scheme 208

1. Ensure ignition is off. To test vacuum sensor supply voltage, disconnect electrical connector from vacuum sensor. Vacuum sensor is located at passenger's side front corner of engine and contains Black 3-pin electrical connector with Brown, Violet/White and Yellow/Red wires. (Scheme 207)
2. Turn ignition on. Using voltmeter, check vacuum sensor supply voltage between terminals E2 and VC on wiring harness side of electrical connector for vacuum sensor. (Scheme 208) E2 and VC terminals are the 2 outer terminals. DO NOT use center terminal.
3. Vacuum sensor supply voltage should be 4.5-5.5 volts. If vacuum sensor supply voltage is not within specification, check wiring circuit. See «WIRING DIAGRAMS»(ref-133228) article. If vacuum sensor supply voltage is within specification, turn ignition off. Reinstall electrical connector on vacuum sensor.
4. To test vacuum sensor output voltage, disconnect vacuum hose from vacuum sensor. Remove glove box for access to Engine Control Module (ECM). For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article.
5. Note ECM electrical connector terminals. (Scheme 145) Connect voltmeter between terminals No. 14 (Violet/White wire) at ECM electrical connector E9 and No. 18 (Brown wire) at ECM electrical connector E8. (Scheme 145) This is the HCLS and E1 terminals at ECM.
6. Turn ignition on. Measure and record vacuum sensor output voltage under ambient atmospheric pressure. Attach vacuum pump to bottom of vacuum sensor. Apply vacuum in specified increments and measure vacuum sensor output voltage drop at each increment. See «VACUUM SENSOR OUTPUT VOLTAGE DROP SPECIFICATIONS»(ref-133221-S36015986242002021900000) table. Turn ignition off. Replace vacuum sensor if vacuum sensor output voltage drop is not within specification. VACUUM SENSOR OUTPUT VOLTAGE DROP SPECIFICATIONS Applied Vacuum - In. Hg Voltage Drop 3.94.3-.5 7.87.7-.9 11.81 1.1-1.3 15.75 1.5-1.7 19.69 1.9-2.1

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.

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

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

Scheme 209

Scheme 210

1. Vehicle speed sensor is mounted on transaxle and contains a 3-pin electrical connector. (Scheme 209) Raise and support vehicle so one front wheel is off the ground. Place transaxle in Neutral.
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 2 and 3 on vehicle speed sensor while rotating the front wheel with electrical connector installed on vehicle speed sensor. (Scheme 210) Voltage should change from zero volts to 10-14 volts several times while rotating the front wheel. If voltage is not as specified, it may be necessary to verify that battery voltage exists at terminal No. 1 on vehicle speed sensor. If battery voltage exists, replace vehicle speed sensor. See «VEHICLE SPEED SENSOR»(ref-133226-S27389256412002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. If battery voltage does not exist, check wiring circuit to electrical terminal No. 1 on vehicle speed sensor. See «WIRING DIAGRAMS»(ref-133228) article. If necessary to check GAUGE No. 1 fuse, this fuse is located is located in fuse/relay box behind driver's side of instrument panel.

Scheme 211

Scheme 212

1. Vehicle speed sensor is mounted on transaxle and contains a 3-pin electrical connector. (Scheme 209) Remove vehicle speed sensor. Connect voltmeter positive lead to terminal No. 3 (outer terminal) and negative lead to terminal No. 2 (center terminal) on vehicle speed sensor. (Scheme 211)and (Scheme 212).
2. Using jumper wires, connect positive battery terminal to terminal No. 1 (outer terminal) and negative battery terminal to terminal No. 2 (center terminal) on vehicle speed sensor. (Scheme 211)and (Scheme 212).
3. While rotating vehicle speed sensor shaft, ensure voltage changes from zero volts to at least 11 volts. Voltage should change 4 times per revolution of shaft. Replace vehicle speed sensor if voltage does not change as specified. See «VEHICLE SPEED SENSOR»(ref-133226-S27389256412002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

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. Instrument cluster then converts 4-pulse input signal to a rectangular waveform and then sends vehicle speed signal to Engine Control Module (ECM). 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.

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. Instrument cluster then converts 4-pulse input signal to a rectangular waveform and then sends vehicle speed signal to Engine Control Module (ECM). 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.

Wheel speed sensors on each wheel deliver an input signal to brake Electronic Control Unit (ECU) for the Anti-Lock Brake System (ABS). 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). 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 is mounted on transaxle. Testing information 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.

Scheme 213

Scheme 214

Scheme 215

1. Vehicle speed sensor is mounted near rear of transmission or transfer case and contains a 3-pin electrical connector. (Scheme 213) Electrical connector contains Blue, Green/Red and Pink wires.
2. Remove vehicle speed sensor. Connect voltmeter positive lead to terminal No. 3 (outer terminal) and negative lead to terminal No. 2 (center terminal) on vehicle speed sensor. (Scheme 212), (Scheme 214) and (Scheme 215).
3. Using jumper wires, connect positive battery terminal to terminal No. 1 (outer terminal) and negative battery terminal to terminal No. 2 (center terminal) on vehicle speed sensor. (Scheme 212), (Scheme 214) and (Scheme 215).
4. While rotating vehicle speed sensor shaft, ensure voltage changes from zero volts to at least 11 volts. Voltage should change 4 times per revolution of shaft. Replace vehicle speed sensor if voltage does not change as specified. See «VEHICLE SPEED SENSOR»(ref-133226-S27389256412002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

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.

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.

Scheme 216

1. Remove A/C compressor clutch relay from relay box on firewall at driver's side front corner of engine compartment. (Scheme 224)
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 216)
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 216) 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.

Scheme 217

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 217)
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 217) Replace A/F heater relay if defective.

1. Remove A/F heater relay from fuse/relay box at driver's side front corner of engine compartment. To test A/F heater relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on A/F heater relay. (Scheme 216)
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 216) Replace A/F heater relay if defective.

CIRCUIT OPENING RELAY

1. Ensure ignition is off. Remove circuit opening relay. See «CIRCUIT OPENING RELAY LOCATION»(ref-133221-S21767427192002021900000) table. (Scheme 218)- (Scheme 227). CIRCUIT OPENING RELAY LOCATION (1) Application Location Camry & Camry Solara In Fuse/Relay Box At Driver's Side Front Corner Of Engine Compartment Celica In Fuse/Relay Box At driver's side Front Corner Of Engine Compartment, Just In Front Of Strut Tower Corolla Center Relay In Relay Box Behind Driver's Side Kick Panel ECHO In Fuse/Relay Box Behind Driver's Side Of Instrument Panel Highlander In Relay Box Just Above Driver's Side Kick Panel MR2 In Relay Box On Firewall At Driver's Side Front Corner Of Engine Compartment Prius & RAV4 In Fuse/Relay Box At Driver's Side Front Corner Of Engine Compartment Tacoma Behind Lower Instrument Panel Cover, Next To Driver's Side Of Steering Column (1) Circuit opening relay may be marked as CIR OPN relay.
2. To test circuit opening relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on circuit opening relay. see scheme 109and see scheme 110.
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 109and see scheme 110. Replace circuit opening relay if defective.

Scheme 218

Scheme 219

Scheme 220

Scheme 221

Scheme 222

Scheme 223

Scheme 224

Scheme 225

Scheme 226

Scheme 227

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-133221-S41025385542002021900000) table. 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 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
2. To test EFI main relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on EFI main relay. see scheme 109and see scheme 110.
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 109and see scheme 110. Replace EFI main relay if defective.

HTR SUB1 RELAY

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

Scheme 228

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 228)
2. Note terminals on HTR SUB1 relay. (Scheme 228) 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 WIRING DIAGRAMS article.

1. Remove IG2 relay from relay box on firewall at driver's side front corner of engine compartment. (Scheme 224)
2. To test IG2 relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on IG2 relay. see scheme 112
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 112 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 WIRING DIAGRAMS article.

1. Remove IG2 relay from relay box located at driver's side front corner of engine compartment. (Scheme 226)
2. To test IG2 relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on IG2 relay. see scheme 112
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 112 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, OVERHAUL & 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 (Celica, Corolla, ECHO, Highlander, MR2, Prius & RAV4)

1. To check for fuel injector operation, remove No. 2 cylinder head cover on top of engine (if equipped) any other components for access to fuel injectors. Using stethoscope, listen for clicking sound at each fuel injector, or feel for fuel injector operation at fuel injector with engine cranking or with engine running. If fuel injector operation does not exist, check for loose connection at electrical connector for fuel injector. If electrical connector for fuel injector is okay, go to next step.
2. Ensure ignition is off. Disconnect electrical connector at fuel injector. Using ohmmeter, check resistance between electrical terminals on fuel injector. Replace fuel injector if resistance is not within specification. See «FUEL INJECTOR RESISTANCE»(ref-133221-S40320021852002021900000) table. See «FUEL RAILS & FUEL INJECTORS»(ref-133226-S05944270142002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
3. If fuel injector operates and fuel injector resistance is within specification, go to next step. If fuel injector resistance is within specification but fuel injector does not operate, check wiring circuit to fuel injector. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists in fuel injector or wiring circuit and misfire exists, 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.
4. To check fuel injector volume, remove fuel injector. See «FUEL RAILS & FUEL INJECTORS»(ref-133226-S05944270142002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
5. On Celica, Corolla, ECHO and MR2, remove fuel pipe clamp from end of fuel pipe at end of fuel rail if not previously done. Perform STEP 1 in illustration. (Scheme 230)- (Scheme 232) and (Scheme 234). Ensure area around fuel pipe and disconnect fitting is clean. Depress both sides of retainer and pull fuel pipe with disconnect fitting from fuel pipe fitting. Perform STEP 2 in illustration. (Scheme 230)- (Scheme 232) and (Scheme 234). Use care when disconnecting fuel pipe, as some residual fuel pressure may still exist in fuel system. Go to step 8.
6. On Highlander and RAV4, remove fuel pipe clamp from end of fuel pipe at end of fuel rail if not previously done. (Scheme 233)and (Scheme 236). Depress both tabs and pull fuel pipe with disconnect fitting from fuel pipe fitting. (Scheme 233)and (Scheme 236). Use care when disconnecting fuel pipe, as some residual fuel pressure may still exist in fuel system. Go to step 8.
7. On Prius, depress both sides of retainer and pull fuel pipe with disconnect fitting from fuel pipe fitting. (Scheme 235) Use care when disconnecting fuel pipe, as some residual fuel pressure may still exist in fuel system. Go to next step.
8. On all models, purchase appropriate fuel pipe from parts department. See «FUEL PIPE IDENTIFICATION»(ref-133221-S14872551772002021900000) table. Remove fuel pipe connector from end of NEW fuel pipe. see scheme 125and see scheme 130. FUEL PIPE IDENTIFICATION Application Fuel Pipe Part No. Celica 1.8L 1ZZ-FE 23901-22100 1.8L 2ZZ-GE 23271-88600 Corolla 23901-22010 ECHO 23901-21020 Or 23901-22010 Highlander 23901-28070 MR2 23901-22070 Prius 23901-21020 RAV4 23901-22110
9. Install fuel pipe connector on fuel pipe fitting and retainer (if equipped). see scheme 126 Ensure fuel pipe connector is securely attached on fuel pipe fitting and retainer (if equipped) is fully seated.
10. Connect delivery hose from Fuel Injector Measuring Set (SST 09268-41047) to fuel pipe connector. Check that grommet (if equipped) and "O" ring are installed on top of fuel injector. Using clamp and union from fuel injector measuring set, connect fuel injector to delivery hose. see scheme 126
11. Place vinyl tube on end of fuel injector to prevent fuel spillage. Place fuel injector into a clean graduated container.
12. Connect Toyota hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 129)- (Scheme 135). Turn ignition on and then turn hand-held tester on. Select ACTIVE TEST MODE on hand-held tester. Using hand-held tester manufacturer's instructions, activate fuel pump. NOTE: If hand-held tester is not available, fuel pump may also be operated to pressurize fuel system by applying battery voltage to electrical terminals on fuel pump. For operating of fuel pump, see appropriate «FUEL PUMP RESISTANCE & OPERATION»(ref-133221-S22385185732002021900000) procedure under FUEL DELIVERY under FUEL SYSTEMS.
13. Connect Fuel Injector Tester (09842-30080) to fuel injector for 15 seconds. see scheme 128 Measure fuel injector volume. Test each fuel injector 2-3 times. Replace fuel injector if fuel injector volume is not within specification. See «FUEL INJECTOR VOLUME SPECIFICATIONS»(ref-133221-S38944995152002021900000) table. Ensure difference between fuel injector volume on all fuel injectors is within specification. See «FUEL INJECTOR VOLUME SPECIFICATIONS»(ref-133221-S38944995152002021900000) table.
14. Disconnect fuel injector tester. Ensure fuel leakage from end of fuel injector does not exceed one drop in 12 minutes. Replace fuel injector if leakage exceeds one drop in 12 minutes. Disconnect negative battery cable. Remove test equipment.
15. On Celica, Corolla, ECHO, MR2 and Prius, DO NOT reuse old retainer when installing fuel pipe on fuel pipe fitting. Always use a NEW retainer. Apply light coat of engine oil on tip of fuel pipe fitting to allow for ease of disconnect fitting and fuel pipe installation. Using NEW retainer, install fuel pipe on fuel pipe fitting until "click" sound is heard. DO NOT reuse old retainer. Pull on fuel pipe to ensure fuel pipe is properly locked on fuel pipe fitting. Reinstall fuel pipe clamp (if equipped). Go to step 17.
16. On Highlander and RAV4, install fuel pipe on fuel pipe fitting. Pull on fuel pipe to ensure fuel pipe is properly locked on fuel pipe fitting. Reinstall fuel pipe clamp. Go to next step.
17. On all models, install negative battery cable. Check for fuel leaks by operating the fuel pump by using hand-held tester or connecting battery voltage to fuel pump. NOTE: On Celica, it may be possible that power sun roof may not operate properly after battery was disconnected. If power sun roof does not operate properly, perform power sun roof reinitialization procedure. See appropriate «POWER SUN ROOF REINITIALIZATION PROCEDURE»(ref-133221-S15755059972002032500000) under PROGRAMMING.

Fuel Injectors (Tacoma)

1. To check for fuel injector operation, using stethoscope, listen for clicking sound at each fuel injector, or feel for fuel injector operation at fuel injector with engine cranking or with engine running. If fuel injector operation does not exist, check for loose connection at electrical connector for fuel injector. If electrical connector for fuel injector is okay, go to next step.
2. Ensure ignition is off. Disconnect electrical connector at fuel injector. Using ohmmeter, check resistance between electrical terminals on fuel injector. Replace fuel injector if resistance is not within specification. See «FUEL INJECTOR RESISTANCE»(ref-133221-S40320021852002021900000) table. See FUEL RAILS & FUEL INJECTORS under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
3. If fuel injector operates and fuel injector resistance is within specification, go to next step. If fuel injector resistance is within specification but fuel injector does not operate, check wiring circuit to fuel injector. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists in fuel injector or wiring circuit and misfire exists, 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.
4. To check fuel injector volume, remove fuel injector. See «FUEL RAILS & FUEL INJECTORS»(ref-133226-S05944270142002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Ensure area around fuel hoses on fuel filter is clean. Remove union bolts with gaskets, and disconnect fuel hose from fuel filter. (Scheme 237)
5. Install union, delivery hose, gaskets and union bolt from Fuel Injector Measuring Set (SST 09268-41047) on fuel filter. (Scheme 237) Tighten union bolt to 21 ft. lbs. (29 N.m).
6. Check that "O" ring is installed on top of fuel injector. Using clamp and union from fuel injector measuring set, connect fuel injector to delivery hose. (Scheme 237)
7. Remove fuel pressure regulator from fuel rail. See «FUEL PRESSURE REGULATOR»(ref-133226-S09916981002002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Using NEW "O" ring, install union on fuel pressure regulator. (Scheme 237) Connect delivery hose to union and fuel return hose on fuel pressure regulator.
8. Place vinyl tube on end of fuel injector to prevent fuel spillage. Place fuel injector into a clean graduated container.
9. Connect Toyota hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 136) Turn ignition on and then turn hand-held tester on. Select ACTIVE TEST MODE on hand-held tester. Using hand-held tester manufacturer's instructions, activate fuel pump. NOTE: If hand-held tester is not available, fuel pump may also be operated to pressurize fuel system by applying battery voltage to electrical terminals on fuel pump. For operating of fuel pump, see appropriate «FUEL PUMP RESISTANCE & OPERATION»(ref-133221-S22385185732002021900000) procedure under FUEL DELIVERY under FUEL SYSTEMS.
10. Connect Fuel Injector Tester (09842-30070) to fuel injector for 15 seconds. see scheme 128 Measure fuel injector volume. Test each fuel injector 2-3 times. Replace fuel injector if fuel injector volume is not within specification. See «FUEL INJECTOR VOLUME SPECIFICATIONS»(ref-133221-S38944995152002021900000) table. Ensure difference between fuel injector volume on all fuel injectors is within specification. See «FUEL INJECTOR VOLUME SPECIFICATIONS»(ref-133221-S38944995152002021900000) table.
11. Disconnect fuel injector tester. Ensure fuel leakage from end of fuel injector does not exceed one drop in 12 minutes. Replace fuel injector if leakage exceeds one drop in 12 minutes. Disconnect negative battery cable. Remove test equipment.
12. Using NEW gaskets, install fuel hose on top of fuel filter. Tighten union bolt to 21 ft. lbs. (29 N.m). Reinstall fuel pressure regulator. Install negative battery cable. Check for fuel leaks by operating the fuel pump by using hand-held tester or connecting battery voltage to fuel pump.

FUEL INJECTOR RESISTANCE

FUEL INJECTOR VOLUME SPECIFICATIONS

Scheme 229

Scheme 230

Scheme 231

Scheme 232

Scheme 233

Scheme 234

Scheme 235

Scheme 236

Fuel Cut System (Camry & Highlander)

1. Connect Toyota hand-held tester or scan tool to data link connector No. 3 at driver's side of instrument panel. (Scheme 127)and (Scheme 132). Hand-held tester or scan tool is used to read engine RPM. Start engine and warm engine 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, Corolla, ECHO, MR2, RAV4 & Tacoma)

1. Connect Toyota hand-held tester or scan tool to data link connector No. 3 at driver's side of instrument panel. (Scheme 128)- (Scheme 136). 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-133221-S10361604632002021900000) table. Shut engine off. Remove hand-held tester or scan tool.

FUEL CUT SYSTEM SPECIFICATIONS (1)

Fuel Cut System (Prius)

Scheme 237

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 238) 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 at driver's side of instrument panel. (Scheme 134) 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.

Scheme 238

Scheme 239

Scheme 240

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See «IDLE SPEED & MIXTURE»(ref-133193-S30658159542002021900000) 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 239) Data link connector No. 3 is located behind driver's side of instrument panel. (Scheme 129)and (Scheme 131).
3. Start engine and note engine speed. Engine speed should increase to 900-1300 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 and remove jumper wire. Go to next step.
4. To test Idle Air Control (IAC) valve operation, remove IAC valve from throttle body. See «THROTTLE BODY»(ref-133226-S29566029082002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Check that valve on inside of IAC valve is half open. (Scheme 240)and (Scheme 241). Reinstall electrical connector on IAC valve.
5. Disconnect electrical connector from Engine Coolant Temperature (ECT) sensor. On Celica, ECT sensor is located on flywheel end of cylinder head and contains Gray electrical connector with Green and Brown wires. On ECHO, ECT sensor is located on flywheel end of cylinder head and contains Gray electrical connector with Red/Blue and Brown wires.
6. On all models, 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 240)and (Scheme 241).
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. 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 THEORY & OPERATION article. See «WIRING DIAGRAMS»(ref-133228) article. On all models, if wiring circuit and ECM are okay, replace IAC valve.

Scheme 241

Scheme 242

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See «IDLE SPEED & MIXTURE»(ref-133193-S30658159542002021900000) 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 TE1 and E1 on data link connector No. 1. (Scheme 242) Data link connector No. 1 is located at driver's side of engine compartment, near strut tower.
3. Start engine and note engine speed. Engine speed should increase to 900-1300 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 and remove jumper wire. Go to next step.
4. To test Idle Air Control (IAC) valve operation, remove IAC valve from throttle body. See «THROTTLE BODY»(ref-133226-S29566029082002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Check that valve on inside of IAC valve is half open. (Scheme 243) Reinstall electrical connector on IAC valve.
5. Disconnect electrical connector from Engine Coolant Temperature (ECT) sensor. ECT sensor is located on flywheel end of cylinder head and contains Dark Gray electrical connector with White and Brown wires.
6. Turn ignition on. Check that valve on inside of IAC valve moves. Repeatedly disconnect and reconnect electrical connector for IAC valve several times while checking that valve on inside of IAC valve opens and closes. (Scheme 243)
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. ECM is located behind stereo on instrument panel, just in front of center console. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. It may be necessary to remove bolts from ECM so electrical connectors can be accessed on ECM. See «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. See «WIRING DIAGRAMS»(ref-133228) article. If wiring circuit and ECM are okay, replace IAC valve.

Scheme 243

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-133226-S29566029082002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & 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 seconds. (Scheme 244) 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, see «THEORY & OPERATION»(ref-133195) article. See «WIRING DIAGRAMS»(ref-133228) article. 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-133193-S30658159542002021900000) 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 239) Data link connector No. 3 is located behind driver's side of instrument panel. (Scheme 133)
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 and remove jumper wire. Go to next step.
4. To test IAC operation, remove IAC valve from throttle body. See «THROTTLE BODY»(ref-133226-S29566029082002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Check that valve on inside of IAC valve is half open. (Scheme 241) 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 seconds. (Scheme 241) 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, see «THEORY & OPERATION»(ref-133195) article. See «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article for removal of components for access to ECM. See «WIRING DIAGRAMS»(ref-133228) article. 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-133193-S30658159542002021900000) 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 239) Data link connector No. 3 is located behind driver's side of instrument panel. (Scheme 135)
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 and remove jumper wire. Go to next step.
4. To test Idle Air Control (IAC) valve operation, remove IAC valve from throttle body. See «THROTTLE BODY»(ref-133226-S29566029082002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Check that valve on inside of IAC valve is half open. (Scheme 244) 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 seconds. (Scheme 244) 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, see «THEORY & OPERATION»(ref-133195) article. See «WIRING DIAGRAMS»(ref-133228) article. 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-133193-S30658159542002021900000) 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 239) Data link connector No. 3 is located behind driver's side of instrument panel. (Scheme 136)
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 and remove jumper wire. Go to next step.
4. To test Idle Air Control (IAC) valve operation, remove IAC valve from throttle body. See «THROTTLE BODY»(ref-133226-S29566029082002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Check that valve on inside of IAC valve is half open. (Scheme 245) 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 245)
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. ECM is located behind glove box. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. See «WIRING DIAGRAMS»(ref-133228) article. If wiring circuit and ECM are okay, replace IAC valve.

Scheme 244

Scheme 245

Scheme 246

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 listing for operating sound at throttle control motor and note that no grinding noise is heard at throttle control motor and throttle body. Accelerator pedal position sensor is located near top of accelerator pedal and throttle control motor is located on the throttle body. (Scheme 246)
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 behind glove box. For illustration of ECM location, see THEORY & OPERATION article. For wiring of throttle control motor, see «WIRING DIAGRAMS»(ref-133228) article. For testing of throttle control motor, go to step 6.
4. To test accelerator pedal position sensor, turn ignition off. Connect Toyota hand-held tester or scan tool to data link connector No. 3 at driver's side of instrument panel. (Scheme 127)and (Scheme 128). Turn ignition on. Hand-held tester or scan tool is used to read throttle valve opening which is displayed as a percentage. Ensure Malfunction Indicator Light (MIL) on instrument panel is not illuminated. 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.
5. 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 next step. If throttle valve opening is not at least 60 percent, problem may exist in accelerator position sensor, wiring circuit or ECM. If necessary to check wiring between ECM and accelerator pedal position sensor, see «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind glove box. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. For testing of accelerator pedal position sensor, see «ACCELERATOR PEDAL POSITION SENSOR»(ref-133221-S16384707362002021900000) under ENGINE SENSORS & SWITCHES.
6. To test throttle control motor, disconnect electrical connector from side of throttle body. (Scheme 246) Note electrical terminal identification on throttle body. (Scheme 247) Using ohmmeter, check resistance between specified terminals on throttle control motor. See «THROTTLE CONTROL MOTOR RESISTANCE»(ref-133221-S35854591892002032500000) 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 Ohms @ 68°F (20°C) M+ & M-.3-100.0 VC & E2 1.2-3.2
7. To test Throttle Position (TP) sensor, disconnect electrical connector from side of throttle body. (Scheme 246) Note electrical terminal identification on throttle body. (Scheme 247) 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).

Celica, Corolla, 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.

Scheme 247

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 248) 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 248) 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-133221-S11553571842002021900000) under ENGINE SENSORS & SWITCHES.

Note. A standard type manual transaxle and a sequential manual transaxle may be used. On models with a standard type manual transaxle, the driver operates the clutch and shifts the transaxle. On models with sequential manual transaxle, the transaxle is electronically controlled and the clutch is operated and transaxle is shifted hydraulically by moving shift lever forward or backward. 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. 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).

Scheme 248

Scheme 249

Scheme 250

Scheme 251

Scheme 252

1. Ensure throttle cable and throttle lever on throttle body move smoothly. Note location of throttle control motor on throttle body. (Scheme 249)
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, see «THEORY & OPERATION»(ref-133195) article. To remove components for access to ECM, see «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. Go to step 12 for testing of throttle control motor. For wiring of throttle control motor, see «WIRING DIAGRAMS»(ref-133228) article.
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 at driver's side of instrument panel. (Scheme 133) 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 «WIRING DIAGRAMS»(ref-133228) article.
8. Access ECM. ECM is located on inside of firewall, directly behind driver's seat and luggage compartment. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. To remove components for access to ECM, see «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
9. Ensure ignition is on. Using voltmeter, check voltage between ECM terminals VPA (Blue wire) and E2 (Brown wire) with accelerator pedal released and with accelerator pedal fully depressed. (Scheme 250) 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. Go to step 16 for testing of accelerator pedal position sensor. For wiring of accelerator pedal position sensor, see «WIRING DIAGRAMS»(ref-133228) article.
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 249) 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-133226-S29566029082002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
13. Note terminal identification on throttle control motor. (Scheme 251) Using ohmmeter, check resistance between specified terminals on throttle control motor. See «THROTTLE CONTROL MOTOR RESISTANCE»(ref-133221-S01276232712002021900000) 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-133226-S29566029082002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
15. Disconnect electrical connector at TP sensor. (Scheme 249) Using ohmmeter, check resistance between terminals E2 and VC on TP sensor. (Scheme 252) Replace TP sensor if resistance is not 1200-3200 ohms at 68°F (20°C). See «THROTTLE BODY»(ref-133226-S29566029082002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & 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-133226-S29566029082002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
17. Disconnect electrical connector at accelerator pedal position sensor. (Scheme 249) Using ohmmeter, check resistance between terminals E2 and VC on accelerator pedal position sensor. (Scheme 253) Replace accelerator pedal position sensor if resistance is not 1200-3200 ohms at 68°F (20°C). See «THROTTLE BODY»(ref-133226-S29566029082002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

Scheme 253

Scheme 254

Scheme 255

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, Hybrid Vehicle Control Electronic Control Unit (HV ECU) and Engine Control Module (ECM).
2. To inspect ETCS operation, ensure ignition is off. Disconnect electrical connector at throttle control motor on throttle body. (Scheme 254)
3. To test TP sensor operation, connect Toyota hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 134) Turn ignition on. Hand-held tester is used to read throttle valve opening which is displayed as a percentage.
4. Rotate throttle linkage to full throttle while reading throttle valve opening on hand-held tester which is accessed by THROTTLE POS under CURRENT DATA. Throttle valve opening should be at 60 percent or more. If throttle valve opening is at least 60 percent, go to next step. If throttle valve opening is not at least 60 percent, problem may exist in TP sensor, wiring circuit or ECM. Go to step 10 for testing of TP sensor. If necessary to check wiring between ECM and TP sensor, see «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind glove box. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article.
5. Turn ignition off. Reinstall electrical connector at throttle control motor. It is necessary to put transit in inspection mode so engine will run continuously. 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.
6. Check that master warning light on instrument cluster at center of instrument panel is flashing to indicate inspection mode operation. (Scheme 238) 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.
7. Warm engine to normal operating temperature. To check charging rate of High Voltage (HV) battery, apply brake and place shift lever in Drive and check that engine shuts off. If engine shuts off, go to next step. If engine does not shut off, charging rate of HV battery may be low. Place shift lever in Park and allow engine to run for a while to charge the HV battery. After engine has ran for a while, place shift lever in Drive and check that engine shuts off. If engine now shuts off, go to next step. If engine does not shut off, it may be necessary to place shift lever in Park and allow engine to run for a while to charge the HV battery.
8. With engine idling, turn A/C switch to ON and OFF positions while noting engine idle speed. Idle speed should be 950-1050 RPM with A/C switch in OFF position and 1150-1250 RPM with A/C switch in ON position. If idle speed is not as specified, go to next step. If idle speed is as specified, shut engine off. Remove hand-held tester.
9. To test throttle control motor, disconnect electrical connector for throttle control motor. (Scheme 254) Using ohmmeter, check resistance between terminals No. 1 and 2 on electrical connector for throttle control motor. (Scheme 255) Resistance should be.3-100.0 ohms at 68°F (20°C). 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. See «THROTTLE BODY»(ref-133226-S29566029082002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
10. To test TP sensor, disconnect electrical connector at TP sensor. (Scheme 254) Using ohmmeter, check resistance between terminals E2 and VC on TP sensor. (Scheme 256) Resistance should be 1200-3200 ohms at 68°F (20°C). If resistance is within specification, reinstall electrical connector. Go to next step. If resistance is not within specification, replace TP sensor. See «THROTTLE BODY»(ref-133226-S29566029082002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
11. It may be necessary to check accelerator pedal position sensor. See «ACCELERATOR PEDAL POSITION SENSOR»(ref-133221-S16384707362002021900000) under ENGINE SENSORS & SWITCHES. If TP sensor, throttle control motor and accelerator pedal position sensor are okay, but ETCS does not operate properly, it may be necessary to check wiring between ECM and TP sensor, ECM and throttle control motor, ECM and HV ECU. See «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind glove box. HV ECU is located below carpet on floor panel, just below passenger's side of instrument panel. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article.

1. Check that throttle linkage moves freely at throttle body. To check vacuum supply at throttle body, start engine and allow engine to idle. Note vacuum port location on throttle body. (Scheme 257)
2. Check that vacuum and no vacuum exist at specified vacuum ports on throttle body with engine idling and with engine at more than idle. See «THROTTLE BODY VACUUM SUPPLY»(ref-133221-S15767553112002021900000) table. Repair or replace components if vacuum supply is not as designated.

THROTTLE BODY VACUUM SUPPLY

Scheme 256

IGNITION SYSTEMS

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

See KNOCK SENSOR under ENGINE SENSORS & SWITCHES.

EMISSION SYSTEMS & SUB-SYSTEMS

Note. For emission system component location, refer to illustrations. (Scheme 258)- (Scheme 265). On Camry and Highlander, illustration was not available from manufacturer.

Scheme 257

Scheme 258

Scheme 259

Scheme 260

Scheme 261

Scheme 262

Scheme 263

Scheme 264

System Check (Tacoma 2.7L 3RZ-FE)

1. Remove cap and filter from top of EGR vacuum modulator. (Scheme 265) 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 266) 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 at driver's side of instrument panel. (Scheme 136) 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 266) 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 267) 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 265

Scheme 266

EGR Gas Temperature Sensor (Tacoma 2.7L 3RZ-FE)

See EGR GAS TEMPERATURE SENSOR under ENGINE SENSORS & SWITCHES.

EGR Vacuum Modulator (Tacoma 2.7L 3RZ-FE)

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 at driver's side of instrument panel for monitoring engine RPM. (Scheme 136)
2. Mark vacuum hose locations and disconnect vacuum hoses from EGR vacuum modulator. (Scheme 265)
3. Block ports "P" and "R" on EGR vacuum modulator. (Scheme 267) 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 267) 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 267

1. Disconnect electrical connector from EGR Vacuum Switching Valve (VSV). (Scheme 265) EGR VSV is located on bracket, near throttle body and contains Green 2-pin electrical connector with White/Red and Red/Black wires.
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 268)
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 268) Replace EGR VSV if defective.

EGR Valve (Tacoma 2.7L 3RZ-FE)

1. Remove EGR valve. See «EGR VALVE»(ref-133226-S09543119472002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
2. Inspect EGR valve for restricted passages caused by carbon deposits. Using vacuum pump, apply vacuum directly to EGR valve and ensure valve opens. Release vacuum and ensure valve closes. Replace EGR valve if defective.

HYDROCARBON ADSORBER CATALYST SYSTEM (PRIUS)

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

Scheme 268

Scheme 269

Scheme 270

1. Hydrocarbon adsorber may also be referred to as HC adsorber. Start engine and warm engine to normal operating temperature. Shut engine off. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step 3.
2. Connect hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 134) Start engine. Turn hand-held tester on. Select proper mode on hand-held tester to operate HCAC Vacuum Switching Valve (VSV). Go to step 4.
3. Disconnect electrical connector at HCAC Vacuum Switching Valve (VSV). (Scheme 269) HCAC VSV is located on bracket bolted to timing chain end of engine and uses a Brown 2-pin electrical connector with Black and Black/White wires. Apply battery voltage and ground to electrical terminals on HCAC VSV to operate HCAC VSV. (Scheme 270) Start engine. Go to next step.
4. With engine idling and HCAC VSV operating, check that rod on actuator is pulled inward and that by-pass valve moves. Actuator and by-pass valve are located at front of three-way catalytic converter on exhaust pipe. (Scheme 271) If rod on actuator is not pulled inward and by-pass valve does not move, shut engine off. Go to next step. If rod on actuator is pulled inward and by-pass valve moves, HCAC system is operating properly. Shut engine off. Reinstall electrical connector at HCAC VSV (if removed) and disconnect hand-held tester (if used).
5. Check vacuum hose and line to HCAC VSV. If vacuum hose and line are okay, check operation of actuator for HCAC system and HCAC VSV. See «ACTUATOR FOR HCAC SYSTEM & BY-PASS VALVE»(ref-133221-S20129943412002021900000) and «HCAC VACUUM SWITCHING VALVE»(ref-133221-S10363413582002021900000). If vacuum hose or line are defective, replace components as necessary and recheck system operation.

Actuator For HCAC System & By-Pass Valve

1. Remove front exhaust pipe. Remove actuator from front exhaust pipe. (Scheme 271) To check the actuator, using vacuum pump, apply 9.83 in. Hg of vacuum to actuator while checking to see if rod on actuator is pulled inward. If rod is pulled inward, actuator is operating properly. If rod is not pulled inward, replace actuator.
2. To check by-pass valve, ensure by-pass valve can be rotated in front exhaust pipe. If by-pass valve will not rotate, replace front exhaust pipe. Reinstall actuator and front exhaust pipe.

HCAC Vacuum Switching Valve

Scheme 271

1. Remove HCAC Vacuum Switching Valve (VSV). (Scheme 269) HCAC VSV is located on bracket bolted to timing chain end of engine and uses a Brown 2-pin electrical connector with Black and Black/White wires.
2. Using ohmmeter, check that continuity exists between electrical terminals on HCAC VSV and that resistance is 33-39 ohms at 68°F (20°C). Replace HCAC VSV if no continuity exists or resistance is not within specification.
3. Ensure no continuity exists between each electrical terminal and body of HCAC VSV body. Replace HCAC VSV if continuity exists between electrical terminal and body of HCAC VSV.
4. To test HCAC VSV operation, apply air pressure to port "E". Ensure air flows from air filter and not from port "F". Perform STEP 1 in illustration. see scheme 174
5. Apply battery voltage and ground to electrical terminals on HCAC VSV. Apply air pressure to port "E". Ensure air flows from port "F" and not from air filter. Perform STEP 2 in illustration. see scheme 174 Replace HCAC VSV if defective.

FUEL EVAPORATIVE SYSTEM

Note. Fuel evaporative system is referred to as fuel EVAP system and may contain different components depending on application. (Scheme 258)- (Scheme 265). When testing fuel EVAP system components, use proper illustration to determine component location.

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. (Scheme 258)- (Scheme 265). 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 (Prius)

Scheme 272

1. Manufacturer states to remove fuel tank for access to Canister Closed Valve Vacuum Switching Valve (CCV VSV) as it is mounted on top of fuel tank. (Scheme 263)
2. Remove fuel tank. See «FUEL PUMP»(ref-133226-S07700574872002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article for removal of fuel tank. Disconnect necessary hoses and electrical connectors for removal of CCV VSV and fresh air valve. Remove bolt and separate fresh air valve from CCV VSV. (Scheme 263) Remove bolts for CCV VSV and remove CCV VSV along with trap filter. Remove bolts and separate trap filter from CCV VSV.
3. Using ohmmeter, check that continuity exists between electrical terminals on CCV VSV and that resistance is 25-30 ohms at 68°F (20°C). Replace CCV VSV if no continuity exists or resistance is not within specification.
4. Using ohmmeter, ensure no continuity exists between each electrical terminal and body of CCV VSV. Replace CCV VSV if continuity exists between electrical terminal and body of CCV VSV.
5. To test CCV VSV operation, apply air pressure to port "A". Ensure air flows from port "B". Perform STEP 1 in illustration. (Scheme 273)
6. Apply battery voltage and ground to electrical terminals on CCV VSV. Apply air pressure to port "A". Ensure air does not flow from port "B". Perform STEP 2 in illustration. (Scheme 273) Replace CCV VSV if defective. Reinstall CCV VSV and fuel tank.

Charcoal Canister

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

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). See «EVAP VACUUM SWITCHING VALVE LOCATION»(ref-133221-S38278027552002021900000) table. (Scheme 258)- (Scheme 265). EVAP VACUUM SWITCHING VALVE LOCATION Application Location Camry On Air Cleaner Housing & Contains Blue or Black 2-Pin Electrical Connector With Black/White & Black/Red Wires Camry Solara On Air Intake Hose, Near Air Cleaner Assembly & Contains Black 2-Pin Electrical Connector With Black/White & Black/Red Wires Celica On Bracket At Rear Of Air Cleaner Housing & Contains Black 2-Pin Electrical Connector With Green/Orange & Black/White Wires Corolla On Bracket At Rear Of Air Cleaner Housing & Contains Black 2-Pin Electrical Connector With Blue/Black & Black Wires ECHO On Bracket At Side Of Air Cleaner Housing & Contains Blue 2-Pin Electrical Connector With Black/Yellow & White/Green Wires Highlander On Rear Of Air Cleaner Housing & Contains Blue 2-Pin Electrical Connector With Black/White & Black/Red Wires MR2 On Air Intake Hose, Near Air Cleaner Assembly & Contains Blue 2-Pin Electrical Connector With Black/Red & White Wires Prius At Passenger's Side Front Corner Of Engine Compartment, Near Air Intake Hose & Contains Blue 2-Pin Electrical Connector With Red/Blue & Black Wires RAV4 On Air Intake Hose, Near Air Cleaner Assembly & Contains Black 2-Pin Electrical Connector With Black/Red & Pink Wires Tacoma On Bracket Bolted To Inside Of Driver's Side Front Fender Panel & Contains Black 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-133221-S08685575312002021900000) 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 30-34 Celica, Corolla, ECHO, MR2 & Prius 27-33 Highlander, RAV4 & Tacoma 30-34
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 274)- (Scheme 278).
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 274)- (Scheme 278). Replace EVAP VSV if defective.

Scheme 273

Scheme 274

Scheme 275

Scheme 276

Scheme 277

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). See «PRESSURE SWITCHING VALVE VACUUM SWITCHING VALVE LOCATION»(ref-133221-S20465360802002021900000) table. (Scheme 258)- (Scheme 264). PRESSURE SWITCHING VALVE VACUUM SWITCHING VALVE LOCATION Application Location Camry On Bracket At Charcoal Canister Near Fuel Tank & Contains Blue 2-Pin Electrical Connector With Violet & Black/Red Wires Camry Solara On Bracket At Charcoal Canister Near Fuel Tank & Contains Blue 2-Pin Electrical Connector With White/Red & Red Wires Celica On Bracket At Charcoal Canister Near Fuel Tank & Contains Blue 2-Pin Electrical Connector With Green/Orange & Black/White Wires Corolla On Bracket At Charcoal Canister Near Fuel Tank & Contains Black 2-Pin Electrical Connector With Red & Black Wires Highlander On Bracket At Charcoal Canister Near Fuel Tank & Contains Blue 2-Pin Electrical Connector With White & Green/Yellow Wires MR2 Below Driver's Side Luggage Compartment, On Bracket At Charcoal Canister Near Fuel Tank & Contains Blue 2-Pin Electrical Connector With Blue/White & Black/Red Wires RAV4 On Bracket At Charcoal Canister Near Fuel Tank & Contains Blue 2-Pin Electrical Connector With Green/Orange & Black/Red Wires Tacoma On Bracket At Charcoal Canister Near Fuel Tank & Contains Blue 2-Pin Electrical Connector With Green/Black & White/Red 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-133221-S29208846802002021900000) 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 30-36 Camry Solara & Celica (1) Corolla 37-44 Highlander, MR2, RAV4 & Tacoma 30-36 (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 279)- (Scheme 281).
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 279)- (Scheme 281). Replace pressure switching valve VSV if defective.

Scheme 278

Scheme 279

Scheme 280

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. (Scheme 263) If necessary to remove fuel tank for access to purge flow switching valve VSV, see «FUEL PUMP»(ref-133226-S07700574872002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & 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 282)
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 282) Replace purge flow switching valve VSV if defective.

Scheme 281

Vapor Pressure Sensor (Camry)

Testing information is not available from manufacturer.

Scheme 282

Scheme 283

Scheme 284

Scheme 285

1. Ensure ignition is off. To test vapor pressure sensor supply voltage, disconnect electrical connector from vapor pressure sensor. See «VAPOR PRESSURE SENSOR LOCATION»(ref-133221-S41264494602002021900000) table. (Scheme 258), (Scheme 260), (Scheme 262) and (Scheme 264). For additional information for obtaining access to vapor pressure sensor, see «VAPOR PRESSURE SENSOR»(ref-133226-S39173639702002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. VAPOR PRESSURE SENSOR LOCATION Application Location Camry Solara On Charcoal Canister Near Fuel Tank & Contains Black 3-Pin Electrical Connector With Blue/Red, Brown & Yellow Wires Corolla On Charcoal Canister Near Fuel Tank & Contains Black 3-Pin Electrical Connector With Brown, Blue & Yellow Wires MR2 On Top Of Fuel Pump Assembly On Fuel Tank, Below Cover Plate & Luggage Compartment Boxes Behind Seats & Contains Black 3-Pin Electrical Connector With Brown, Blue/Red & Green/Black Wires RAV4 On Top Of Fuel Pump Assembly On Fuel Tank, Below Cover Plate & Driver's Side Rear Seat & Contains Black 3-Pin Electrical Connector With Brown, Yellow & Blue/Black Wires
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 283)and (Scheme 284). VC and E2 terminals are the 2 outer terminals. 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 «WIRING DIAGRAMS»(ref-133228) article. See «ENGINE CONTROL MODULE LOCATION»(ref-133221-S32176917752002021900000) table.
4. On Camry Solara and Corolla, to test vapor pressure sensor output voltage, turn ignition on. Disconnect proper vacuum hose from vapor pressure sensor. (Scheme 285)and (Scheme 286). On MR2 and RAV4, to test vapor pressure sensor output voltage, turn ignition on. Remove retaining clip and remove vapor pressure sensor from top of fuel pump assembly. On all models, obtain access to Engine Control Module (ECM). See «ENGINE CONTROL MODULE LOCATION»(ref-133221-S32176917752002021900000) table. ENGINE CONTROL MODULE LOCATION Model (1) Location Camry Solara Behind Glove Box Corolla Behind Stereo On Instrument Panel, Just In Front Of Center Console MR2 On Inside Of Firewall, Directly Behind Driver's Seat & Luggage Compartment RAV4 Near Passenger's Side Kick Panel, Just Below Instrument Panel (1) For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. For information on accessing ECM, see «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
5. Connect voltmeter between specified ECM terminals. (Scheme 287)- (Scheme 290). See «ECM TERMINAL APPLICATION»(ref-133221-S23055521492002021900000) table. ECM TERMINAL APPLICATION Application & Terminal Wire Color Camry Solara E2 Brown PTNK Blue/Red Corolla E2 Brown PTNK Blue MR2 E2 Brown PTNK Green/Black RAV4 E2 Brown PTNK (1) Blue/Black Or White (1) There are 2 different wiring harnesses used. Wire color at designated terminal may vary according to wiring harness used.
6. Ensure ignition is on and electrical connector is installed on vapor pressure sensor. On Camry Solara and Corolla, using vacuum pump, apply.59 in. Hg of vacuum to disconnected vacuum hose port on vapor pressure sensor and note vapor pressure sensor output voltage. On MR2 and RAV4, using vacuum pump, apply.59 in. Hg of vacuum to air passage on vapor pressure sensor and note vapor pressure sensor output voltage. (Scheme 284) On all models, ensure vapor pressure sensor output voltage is within specification. See «VAPOR PRESSURE SENSOR OUTPUT VOLTAGE»(ref-133221-S03475957822002021900000) table.
7. Release vacuum from vapor pressure sensor and note vapor pressure sensor output voltage. Ensure vapor pressure sensor output voltage is within specification. See «VAPOR PRESSURE SENSOR OUTPUT VOLTAGE»(ref-133221-S03475957822002021900000) table.
8. Apply.22 psi (.015 kg/cm 2 ) of pressure to vapor pressure sensor and note vapor pressure sensor output voltage. Ensure vapor pressure sensor output voltage is within specification. See «VAPOR PRESSURE SENSOR OUTPUT VOLTAGE»(ref-133221-S03475957822002021900000) table. Replace vapor pressure sensor if vapor pressure sensor output voltage is not within specification. Turn ignition off.

VAPOR PRESSURE SENSOR OUTPUT VOLTAGE

Scheme 286

Scheme 287

Scheme 288

Scheme 289

Scheme 290

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 Black 3-pin electrical connector with Brown, Red and Blue/Black wires. (Scheme 291) On ECHO, vapor pressure sensor is located on top of fuel pump assembly on top of fuel tank and contains Black 3-pin electrical connector with Brown, Red/White and Black wires. (Scheme 291)
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 291) 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 «WIRING DIAGRAMS»(ref-133228) article. 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 «THEORY & OPERATION»(ref-133195) article. For information on accessing ECM, see «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & 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 291)
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 (Highlander)

Testing information is not available from manufacturer.

Vapor Pressure Sensor (Prius)

Scheme 291

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 Black 3-pin electrical connector with Brown, Blue/Red and Yellow/Red wires. (Scheme 292) 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 292) 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 «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind glove box. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) 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 292)
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.

Scheme 292

Scheme 293

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 293)
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 293) 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 «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind the glove box. For illustration of ECM location, see «THEORY & OPERATION»(ref-133195) article. For information on accessing ECM, see «ENGINE CONTROL MODULE»(ref-133226-S19804702592002021900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & 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 294) 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

1. Remove Positive Crankcase Ventilation (PCV) valve. (Scheme 258)- (Scheme 265). 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.

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 294

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See «IDLE SPEED & MIXTURE»(ref-133193-S30658159542002021900000) in ON-VEHICLE ADJUSTMENTS - 4-CYLINDER article.
2. With engine idling, disconnect and plug vacuum hose at throttle opener. (Scheme 295) 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-133226-S29566029082002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & 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. VVL system is used only on Celica 1.8L 2ZZ-GE. 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).

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 296)
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-133226-S35673850332002021900000) under VARIABLE VALVE LIFT SYSTEM in REMOVAL, OVERHAUL & 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-133226-S35673850332002021900000) under VARIABLE VALVE LIFT SYSTEM in REMOVAL, OVERHAUL & 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 302) 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 302) Replace VVL oil control valve if operation is not as specified.

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.

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 296)- (Scheme 301).. 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-133221-S27548083722002021900000) 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-133226-S07399530522002021900000) under VARIABLE VALVE TIMING SYSTEM in REMOVAL, OVERHAUL & 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-133226-S07399530522002021900000) under VARIABLE VALVE TIMING SYSTEM in REMOVAL, OVERHAUL & 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 302)and see scheme 236. 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 302)and see scheme 236. Replace VVT camshaft timing oil control valve if operation is not as specified.

Scheme 295

Scheme 296

Scheme 297

Scheme 298

Scheme 299

Scheme 300

Scheme 301

Scheme 302