Engine Controls - System & Component Testing - V6 & V8: Other Toyota Sienna I

ACOUSTIC CONTROL INDUCTION SYSTEM (ACIS)

Note. ACIS may also be referred to as Intake Air Control Valve (IACV) system.

Scheme 79

Scheme 80

1. ACIS uses 2 intake air control valves, one on end of air intake chamber and one near throttle bodies. (Scheme 79) Intake air control valve on end of air intake chamber may also be referred to as No. 2 intake air control valve. Intake air control valve near throttle bodies may also be referred to as No. 1 intake air control valve. Operation of actuator valve for each intake air control valve should be checked. Using 3-way connector, connect vacuum gauge in vacuum line to actuator valve for appropriate intake air control valve. (Scheme 80) Start engine. With engine idling, ensure no vacuum reading is obtained.
2. Fully open throttle and ensure vacuum reading momentarily reads approximately 7.9 in. Hg and actuator valve rod pulls inward. If actuator valve rod pulls inward, system is operating properly. If actuator valve rod does not pull inward, go to next step.
3. Disconnect vacuum hose from appropriate actuator valve. Using vacuum pump, apply 7.9 in. Hg of vacuum to actuator valve. Ensure actuator valve rod pulls inward and remains pulled inward for at least one minute. If actuator valve does not operate properly, replace intake air control valve assembly. If actuator valve operates properly, reconnect vacuum hose. Check ACIS control circuit. See «ACOUSTIC CONTROL INDUCTION SYSTEM (ACIS) CONTROL CIRCUIT»(ref-3026-S00305589132000051500000) under COMPUTERIZED ENGINE CONTROLS.

Scheme 81

1. ACIS uses intake air control valve on end of air intake chamber. (Scheme 81) Using 3-way connector, connect vacuum gauge in vacuum line to actuator valve. (Scheme 81) Actuator valve is located at end of air intake chamber. Start engine. With engine idling, ensure no vacuum reading is obtained.
2. Fully open throttle and ensure vacuum reading momentarily reads approximately 7.9 in. Hg and actuator valve rod pulls inward. If actuator valve rod pulls inward, system is operating properly. If actuator valve rod does not pull inward, go to next step.
3. Disconnect vacuum hose from actuator valve. Using vacuum pump, apply 7.9 in. Hg of vacuum to actuator valve. Ensure actuator valve rod pulls inward and remains pulled inward for at least one minute. If actuator valve does not operate properly, replace intake air control valve assembly. If actuator valve operates properly, reconnect vacuum hose. Check ACIS control circuit. See «ACOUSTIC CONTROL INDUCTION SYSTEM (ACIS) CONTROL CIRCUIT»(ref-3026-S00305589132000051500000) under COMPUTERIZED ENGINE CONTROLS.

ELECTRONIC THROTTLE CONTROL SYSTEM (ETCS)

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

Land Cruiser & Tundra 4.7L V8

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

ACOUSTIC CONTROL INDUCTION SYSTEM (ACIS) CONTROL CIRCUIT

Note. ACIS control circuit may also be referred to as Intake Air Control Valve (IACV) system control circuit.

Note. On Avalon models, 2 intake air control valve VSVs are used. Intake air control valve No. 1 VSV is for intake air control valve near throttle bodies which may also be referred to as No. 1 intake air control valve. Intake air control valve No. 2 VSV is for intake air control valve on end of air intake chamber which may also be referred to as No. 2 intake air control valve.

Scheme 82

Scheme 83

Scheme 84

Scheme 85

Scheme 86

1. Remove "V" bank cover located on top of engine. (Scheme 82), (Scheme 83) and (Scheme 84). Disconnect electrical connector and vacuum hoses from intake air control valve Vacuum Switching Valve (VSV). (Scheme 82), (Scheme 83) and (Scheme 84). It may be necessary to remove emission control valve set which contains various vacuum switching valves for access to intake air control valve VSV.
2. Using ohmmeter, check that continuity exists between electrical terminals on intake air control valve VSV and that resistance is 33-39 ohms at 68°F (20°C). If contiunuity exists and resistance is within specification, go to next step. If no continuity exists or resistance is not within specification, replace intake air control valve VSV.
3. Using ohmmeter, ensure no continuity exists between each electrical terminal and body of intake air control valve VSV. If continuity does not exist between electrical terminal and body of intake air control valve VSV, go to next step. If continuity exists between electrical terminal and body of intake air control valve VSV, replace intake air control valve VSV.
4. Apply air pressure to port "B" on intake air control valve VSV. Ensure air flows from the filter. Perform STEP 1 in illustration. (Scheme 85) Apply battery voltage and ground to electrical terminals on intake air control valve VSV. Apply air pressure to port "B" on intake air control valve VSV. Ensure air flows from port "A" and not from the filter. Perform STEP 2 in illustration. (Scheme 85) If intake air control valve VSV operates properly, reinstall intake air control valve VSV and go to next step. If intake air control valve VSV does not operate properly, replace intake air control valve VSV and recheck system operation.
5. On Avalon, Camry and Camry Solara, remove glove box for access to Engine Control Module (ECM). On Sienna, remove passenger's side lower instrument panel cover for access to Engine Control Module (ECM). On all models, for illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminal identification. (Scheme 97), (Scheme 98) and (Scheme 100). Turn ignition on. Using voltmeter, check voltage at specified ECM terminal(s). See «ECM TERMINAL IDENTIFICATION FOR INTAKE AIR CONTROL VALVE VSV»(ref-3026-S27093402192000040300000) table. This is the wire from intake air control valve VSV to ECM. ECM TERMINAL IDENTIFICATION FOR INTAKE AIR CONTROL VALVE VSV Application ECM Connector No. ECM Terminal No. & Wire Color Avalon E4 (1) 17 (Red/Yellow) E5 (2) 15 (White/Red) Camry & Camry Solara E11 17 (Red/Yellow) Sienna E12 17 (Red/Yellow) (1) This is for intake air control valve No. 1 VSV. (2) This is for intake air control valve No. 2 VSV.
6. Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, check for defective EFI main relay, or open or short in wiring harness and connectors between EFI main relay and ECM. See «EFI MAIN RELAY»(ref-3026-S12953225722000041700000) under MOTORS & RELAYS. See appropriate wiring diagram in WIRING DIAGRAMS article.
7. Disconnect hoses from vacuum tank. Vacuum tank is located near driver's side front corner of engine compartment, below battery tray. Apply air pressure to port "B" on vacuum tank. Ensure air flows from port "A". Perform STEP 1 in illustration. (Scheme 86) Apply air pressure to port "A". Ensure air does not flow from port "B". Perform STEP 2 in illustration. (Scheme 86)
8. Plug port "B" on vacuum tank. Using vacuum pump, apply 7.9 in. Hg of vacuum to port "A" on vacuum tank. Perform STEP 3 in illustration. (Scheme 86) Ensure vacuum reading will hold for at least one minute. If vacuum tank is defective, replace vacuum tank and recheck system operation. If vacuum tank is okay, reconnect vacuum hoses and check ECM ground circuit. See appropriate wiring diagram in WIRING DIAGRAMS. If ECM ground circuit is okay, replace ECM. 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.

ENGINE CONTROL MODULE (ECM) POWER SOURCE CIRCUIT

Note. When performing test for 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 appropriate wiring diagram in POWER DISTRIBUTION article in WIRING DIAGRAMS.

Avalon

1. Remove glove box for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminal identification. (Scheme 97)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 16 (Black/White wire) at ECM electrical connector E8 and No. 17 (Brown wire) at ECM electrical connector E5. 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 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. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
3. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 2 (Black/Orange 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 7.
4. Check for defective AM2 fuse. AM2 fuse is located in fuse/relay box at driver's side front corner of engine compartment, near battery and air cleaner. 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 appropriate wiring diagram in WIRING DIAGRAMS article.
5. Check ignition switch. See appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch.
6. Check wiring harness and electrical connectors between battery and ignition switch, and between ignition switch and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.
7. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 8 (Blue/Orange 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 appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. 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.
8. Check for defective EFI No. 1 and No. 2 fuses. EFI No. 1 and No. 2 fuses are located in fuse/relay box at driver's side front corner of engine compartment, near battery and air cleaner. If EFI No. 1 and No. 2 fuses are okay, go to next step. If EFI No. 1 fuse or EFI No. 2 fuse are defective, repair short in wiring harness and components connected to the appropriate EFI fuse. See appropriate wiring diagram in WIRING DIAGRAMS article.
9. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-3026-S12953225722000041700000) under MOTORS & RELAYS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
10. Check for open or short in wiring harness and electrical connectors between terminal No. 8 (Blue/Orange 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 appropriate wiring diagram in WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
11. Check wiring harness and electrical connectors between battery and EFI No. 1 fuse. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.

Camry

1. Remove glove box for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminal identification. (Scheme 98)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 16 (Black/Yellow wire) at ECM electrical connector E7 and No. 17 (Brown wire) at ECM electrical connector E10. 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 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 E10 and body ground. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
3. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 2 (Black/Red wire) at ECM electrical connector E7. 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 7.
4. 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 appropriate wiring diagram in WIRING DIAGRAMS article.
5. Check ignition switch. See appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch.
6. Check wiring harness and electrical connectors between battery and ignition switch, and between ignition switch and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.
7. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 8 (Black/White 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 appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. 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.
8. Check for defective EFI fuse. EFI fuse is located in fuse/relay box at driver's side front corner of engine compartment, near battery and air cleaner. 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 appropriate wiring diagram in WIRING DIAGRAMS article.
9. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-3026-S12953225722000041700000) under MOTORS & RELAYS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
10. Check for open or short in wiring harness and electrical connectors between terminal No. 8 (Black/White 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 appropriate wiring diagram in WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
11. Check wiring harness and electrical connectors between battery and EFI fuse. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.

Camry Solara

1. Remove glove box for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminal identification. (Scheme 98)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 16 (Red wire) at ECM electrical connector E7 and No. 17 (Brown wire) at ECM electrical connector E10. 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 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 E10 and body ground. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
3. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 2 (Black/Red wire) at ECM electrical connector E7. 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 7.
4. 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 appropriate wiring diagram in WIRING DIAGRAMS article.
5. Check ignition switch. See appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch.
6. Check wiring harness and electrical connectors between battery and ignition switch, and between ignition switch and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.
7. 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 appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. 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.
8. Check for defective EFI fuse. EFI fuse is located in fuse/relay box at driver's side front corner of engine compartment, near battery and air cleaner. 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 appropriate wiring diagram in WIRING DIAGRAMS article.
9. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-3026-S12953225722000041700000) under MOTORS & RELAYS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
10. Check for open or 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 appropriate wiring diagram in WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
11. Check wiring harness and electrical connectors between battery and EFI fuse. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.

Land Cruiser

1. Remove glove box door for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminal identification. (Scheme 99)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 16 (Black/Yellow wire) at ECM electrical connector E9 and No. 17 (Brown wire) at ECM electrical connector E6. 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 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 E6 and body ground. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
3. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 9 (Black/Red wire) at ECM electrical connector E9. 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 7.
4. Check for defective IGN fuse. IGN fuse is located in fuse/relay box behind driver's side kick 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 appropriate wiring diagram in WIRING DIAGRAMS article.
5. Check ignition switch. See appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch.
6. Check wiring harness and electrical connectors between battery and ignition switch, and between ignition switch and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.
7. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 10 (Black/White 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 appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. 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.
8. Check for defective EFI fuse. EFI fuse may also be referred to as ECD fuse and is located in fuse/relay box at driver's side front corner of engine compartment, 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 appropriate wiring diagram in WIRING DIAGRAMS article.
9. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-3026-S12953225722000041700000) under MOTORS & RELAYS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
10. Check for open or short in wiring harness and electrical connectors between terminal No. 10 (Black/White wire) at ECM electrical connector E9 and EFI main relay, and for open in ground circuit to EFI main relay. See appropriate wiring diagram in WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
11. Check wiring harness and electrical connectors between battery and EFI fuse. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.

Sienna

1. Remove passenger's side lower instrument panel cover for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminal identification. (Scheme 100)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 16 (Black/Red wire) at ECM electrical connector E8 and No. 17 (Brown wire) at ECM electrical connector E11. 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 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 E11 and body ground. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
3. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 2 (Black/Orange 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 7.
4. 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 appropriate wiring diagram in WIRING DIAGRAMS article.
5. Check ignition switch. See appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch.
6. Check wiring harness and electrical connectors between battery and ignition switch, and between ignition switch and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.
7. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 8 (Yellow/Green 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 appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. 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.
8. Check for defective EFI fuse. EFI fuse is located in fuse/relay box at driver's side front corner of engine compartment, 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 appropriate wiring diagram in WIRING DIAGRAMS article.
9. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-3026-S12953225722000041700000) under MOTORS & RELAYS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
10. Check for open or short in wiring harness and electrical connectors between terminal No. 8 (Yellow/Green 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 appropriate wiring diagram in WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
11. Check wiring harness and electrical connectors between battery and EFI fuse. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.

Tacoma Calif. Emission Vehicles

1. Remove glove box for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminal identification. (Scheme 101)
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 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. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
3. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 2 (Black/Red wire) at ECM electrical connector E5. 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 7.
4. 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 appropriate wiring diagram in WIRING DIAGRAMS article.
5. Check ignition switch. See appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch.
6. Check wiring harness and electrical connectors between battery and ignition switch, and between ignition switch and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.
7. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 8 (Black/Orange wire) at ECM electrical connector E5. 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 appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.
8. Check for defective EFI fuse. EFI fuse is located in fuse/relay box at driver's side front corner of engine compartment, 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 appropriate wiring diagram in WIRING DIAGRAMS article.
9. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-3026-S12953225722000041700000) under MOTORS & RELAYS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
10. Check for open or short in wiring harness and electrical connectors between terminal No. 8 (Black/Orange 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 appropriate wiring diagram in WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
11. Check wiring harness and electrical connectors between battery and EFI fuse. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.

Tacoma Except Calif. Emission Vehicles

1. Remove glove box for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminal identification. (Scheme 102)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 23 (White/Red wire) at ECM electrical connector E5 and No. 16 (Brown wire) at ECM electrical connector E6. 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 article. If voltage is not within specification, check for open in wiring harness and electrical connectors between terminal No. 16 (Brown wire) at ECM electrical connector E6 and body ground. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
3. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-3026-S12953225722000041700000) under MOTORS & RELAYS. 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, 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 appropriate wiring diagram in WIRING DIAGRAMS article.
5. Check for open in wiring harness and electrical connectors between battery, EFI fuse and EFI main relay, and between EFI main relay and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
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 appropriate wiring diagram in WIRING DIAGRAMS article.
7. Check ignition switch. See appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch.
8. Check for open in wiring harness and electrical connectors between ignition switch, IGN fuse and EFI main relay, and for open on White/Black wire between EFI main relay and body ground. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.

Tundra 3.4L V6 Calif. Emission Vehicles

1. Remove glove box for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminal identification. (Scheme 103)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 16 (White/Blue wire) at ECM electrical connector E3 and No. 17 (Brown wire) at ECM electrical connector E5. 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 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. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
3. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 2 (Black/Orange wire) at ECM electrical connector E3. 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 7.
4. 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 appropriate wiring diagram in WIRING DIAGRAMS article.
5. Check ignition switch. See appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch.
6. Check wiring harness and electrical connectors between battery and ignition switch, and between ignition switch and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.
7. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 8 (Black/Yellow 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 appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.
8. 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, near battery. 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 appropriate wiring diagram in WIRING DIAGRAMS article.
9. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-3026-S12953225722000041700000) under MOTORS & RELAYS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
10. Check for open or short in wiring harness and electrical connectors between terminal No. 8 (Black/Yellow 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 appropriate wiring diagram in WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
11. Check wiring harness and electrical connectors between battery and EFI No. 1 fuse. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.

Tundra 3.4L V6 Except Calif. Emission Vehicles

1. Remove glove box for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminal identification. (Scheme 104)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 23 (White/Blue wire) at ECM electrical connector E3 and No. 16 (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 article. If voltage is not within specification, check for open in wiring harness and electrical connectors between terminal No. 16 (Brown wire) at ECM electrical connector E4 and body ground. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
3. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-3026-S12953225722000041700000) under MOTORS & RELAYS. 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 No. 1 fuse. EFI No. 1 fuse is located in fuse/relay box at driver's side front corner of engine compartment, near battery. 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 appropriate wiring diagram in WIRING DIAGRAMS article.
5. Check for open in wiring harness and electrical connectors between battery, EFI No. 1 fuse and EFI main relay, and between EFI main relay and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
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 appropriate wiring diagram in WIRING DIAGRAMS article.
7. Check ignition switch. See appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch.
8. Check for open in wiring harness and electrical connectors between ignition switch, IGN fuse and EFI main relay, and for open on White/Black wire between EFI main relay and body ground. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.

Tundra 4.7L V8

1. Remove glove box for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminal identification. (Scheme 105)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 16 (White/Blue wire) at ECM electrical connector E3 and No. 17 (Brown wire) at ECM electrical connector E6. 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 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 E6 and body ground. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
3. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 9 (Black/Orange wire) at ECM electrical connector E3. 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 7.
4. 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 appropriate wiring diagram in WIRING DIAGRAMS article.
5. Check ignition switch. See appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch.
6. Check wiring harness and electrical connectors between battery and ignition switch, and between ignition switch and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.
7. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 10 (Black/Yellow 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 appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM.
8. 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, near battery. 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 appropriate wiring diagram in WIRING DIAGRAMS article.
9. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-3026-S12953225722000041700000) under MOTORS & RELAYS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
10. Check for open or short in wiring harness and electrical connectors between terminal No. 10 (Black/Yellow 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 appropriate wiring diagram in WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
11. Check wiring harness and electrical connectors between battery and EFI No. 1 fuse. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.

4Runner

1. Remove glove box for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminal identification. (Scheme 106)
2. Turn ignition on. Using voltmeter, check voltage between terminals No. 16 (White/Blue wire) at ECM electrical connector E14 and No. 17 (Brown wire) at ECM electrical connector E10. 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 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 E10 and body ground. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
3. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 2 (Black/Blue wire) at ECM electrical connector E14. 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 7.
4. 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 appropriate wiring diagram in WIRING DIAGRAMS article.
5. Check ignition switch. See appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch.
6. Check wiring harness and electrical connectors between battery and ignition switch, and between ignition switch and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.
7. Ensure ignition is on. Using voltmeter, check voltage between body ground and terminal No. 8 (Gray/Black wire) at ECM electrical connector E14. 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 appropriate wiring diagram in WIRING DIAGRAMS 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.
8. Check for defective EFI fuse. EFI fuse is located in fuse/relay box at driver's side front corner of engine compartment, 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 appropriate wiring diagram in WIRING DIAGRAMS article.
9. Check operation of EFI main relay. See «EFI MAIN RELAY»(ref-3026-S12953225722000041700000) under MOTORS & RELAYS. If EFI main relay operates properly, go to next step. If EFI main relay is defective, replace EFI main relay.
10. Check for open or short in wiring harness and electrical connectors between terminal No. 8 (Gray/Black wire) at ECM electrical connector E14 and EFI main relay, and for open in White/Black wire between EFI main relay and body ground. See appropriate wiring diagram in WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
11. Check wiring harness and electrical connectors between battery and EFI fuse. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.

FUEL PUMP CONTROL CIRCUIT

Scheme 87

1. If using scan tool, go to next step. If scan tool is not available, go to step 3.
2. Check operation of fuel pump by using scan tool. See FUEL PUMP OPERATION under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. Ensure screw at center of fuel pressure pulsation damper rises upward when fuel pump is operated to indicate fuel pressure. Fuel pressure pulsation damper is located on end of fuel rail. (Scheme 87) If screw at center of fuel pressure pulsation damper does not rise upward when fuel pump is operated to indicate fuel pressure, go to step 4. If screw at center of fuel pressure pulsation damper rises upward when fuel pump is operated to indicate fuel pressure, check starter signal circuit. See «STARTER SIGNAL CIRCUIT»(ref-3026-S16626608752000032900000).
3. Remove glove box for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM terminals. (Scheme 97)- (Scheme 98). Turn ignition on. Momentarily connect jumper wire between body ground and FC terminal at ECM to operate fuel pump. See «ECM IDENTIFICATION FOR FUEL PUMP FC TERMINAL (AVALON, CAMRY & CAMRY SOLARA)»(ref-3026-S05043103992000032900000) table. Ensure screw at center of fuel pressure pulsation damper rises upward when fuel pump is operated to indicate fuel pressure. Fuel pressure pulsation damper is located on end of fuel rail. (Scheme 87) If screw at center of fuel pressure pulsation damper does not rise upward when fuel pump is operated to indicate fuel pressure, go to next step. If screw at center of fuel pressure pulsation damper rises upward when fuel pump is operated to indicate fuel pressure, check starter signal circuit. See «STARTER SIGNAL CIRCUIT»(ref-3026-S16626608752000032900000). ECM IDENTIFICATION FOR FUEL PUMP FC TERMINAL (AVALON, CAMRY & CAMRY SOLARA) Application ECM Connector No. ECM Terminal No. & Wire Color Avalon E8 3 (Green/Black) Camry & Camry Solara E7 3 (Green/Red)
4. Check ECM power source circuit. See «ENGINE CONTROL MODULE (ECM) POWER SOURCE CIRCUIT»(ref-3026-S04299435392000051500000). If ECM power source circuit is okay, go to next step. If ECM power source circuit is defective, repair as necessary.
5. Check operation of circuit opening relay. See «CIRCUIT OPENING RELAY»(ref-3026-S38220287942000041700000) under MOTORS & RELAYS. If circuit opening relay operates properly, go to next step. If circuit opening relay is defective, replace circuit opening relay.
6. Remove glove box for access to ECM if not previously done. For illustration of ECM location, see THEORY & OPERATION article. Note ECM terminals. (Scheme 97)- (Scheme 98).
7. Turn ignition on. Using voltmeter, check voltage between body ground and FC terminal at ECM. See «ECM IDENTIFICATION FOR FUEL PUMP FC TERMINAL (AVALON, CAMRY & CAMRY SOLARA)»(ref-3026-S05043103992000032900000) table. Voltage should be 9-14 volts. If voltage is within specification, go to next step. 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 appropriate wiring diagram in WIRING DIAGRAMS article. On Camry and Camry Solara, it may be necessary to check IGN fuse. IGN fuse is located in fuse box behind driver's side of instrument panel. On all models, repair wiring harness or electrical connectors as necessary.
8. Check fuel pump resistance and operation. See «FUEL DELIVERY»(ref-3026-S35804695532000041700000) 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.
9. Check for open in wiring harness and electrical connectors between circuit opening relay and fuel pump, and between fuel pump and body ground. See appropriate wiring diagram in WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
10. Check ECM ground circuit. See appropriate wiring diagram in WIRING DIAGRAMS 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.

Fuel pump control circuit test is not available from manufacturer. If problem exists in fuel pump control circuit, a Diagnostic Trouble Code (DTC) will be stored in Engine Control Module (ECM).

1. If using scan tool, go to next step. If scan tool is not available, go to step 3.
2. Check operation of fuel pump by using scan tool. See FUEL PUMP OPERATION under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If fuel pump does not operate and fuel pressure does not exist in fuel inlet line at fuel filter, go to step 4. If fuel pump operates and fuel pressure exists in fuel inlet line at fuel filter, check starter signal circuit. See «STARTER SIGNAL CIRCUIT»(ref-3026-S16626608752000032900000).
3. Remove passenger's side lower instrument panel cover for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM terminals. (Scheme 100) Turn ignition on. Momentarily connect jumper wire between body ground and terminal No. 3 (Light Green/Red wire) at ECM electrical connector E8 to operate the fuel pump. This is the FC terminal at ECM. Ensure fuel pump operates and fuel pressure exists in fuel inlet line at fuel filter. If fuel pump does not operate and fuel pressure does not exist in fuel inlet line at fuel filter, go to next step. If fuel pump operates and fuel pressure exists in fuel inlet line at fuel filter, check starter signal circuit. See «STARTER SIGNAL CIRCUIT»(ref-3026-S16626608752000032900000).
4. Check ECM power source circuit. See «ENGINE CONTROL MODULE (ECM) POWER SOURCE CIRCUIT»(ref-3026-S04299435392000051500000). If ECM power source circuit is okay, go to next step. If ECM power source circuit is defective, repair as necessary.
5. Check operation of circuit opening relay. See «CIRCUIT OPENING RELAY»(ref-3026-S38220287942000041700000) under MOTORS & RELAYS. If circuit opening relay operates properly, go to next step. If circuit opening relay is defective, replace circuit opening relay.
6. Remove passenger's side lower instrument panel cover for access to ECM if not previously done. For illustration of ECM location, see THEORY & OPERATION article. Note ECM terminals. (Scheme 100)
7. Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 3 (Light Green/Red wire) at ECM electrical connector E8. This is the FC 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 for open in wiring harness and connectors between ECM and circuit opening relay, and between ignition switch and circuit opening relay. See appropriate wiring diagram in WIRING DIAGRAMS article. It may be necessary to check IGN fuse. IGN fuse is located in fuse box behind driver's side of instrument panel. Repair wiring harness or electrical connectors as necessary.
8. Check fuel pump resistance and operation. See «FUEL DELIVERY»(ref-3026-S35804695532000041700000) 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.
9. Check for open in wiring harness and electrical connectors between circuit opening relay and fuel pump, and between fuel pump and body ground. See appropriate wiring diagram in WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
10. Check ECM ground circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. 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.

Tacoma, Tundra 3.4L V6 & 4Runner

1. If using scan tool, go to next step. If scan tool is not available, go to step 3.
2. Check operation of fuel pump by using scan tool. See FUEL PUMP OPERATION under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article. If fuel pump does not operate and fuel pressure does not exist in fuel inlet line at fuel filter, go to step 4. If fuel pump operates and fuel pressure exists in fuel inlet line at fuel filter, check starter signal circuit. See «STARTER SIGNAL CIRCUIT»(ref-3026-S16626608752000032900000).
3. Remove glove box for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM terminals. (Scheme 101)- (Scheme 106). Turn ignition on. Momentarily connect jumper wire between body ground and FC terminal at ECM to operate fuel pump. See «ECM IDENTIFICATION FOR FUEL PUMP FC TERMINAL (TACOMA, TUNDRA 3.4L V6 & 4RUNNER)»(ref-3026-S24058204922000052200000) table. Ensure fuel pump operates and fuel pressure exists in fuel inlet line at fuel filter. If fuel pump does not operate and fuel pressure does not exist in fuel inlet line at fuel filter, go to next step. If fuel pump operates and fuel pressure exists in fuel inlet line at fuel filter, check starter signal circuit. See «STARTER SIGNAL CIRCUIT»(ref-3026-S16626608752000032900000). ECM IDENTIFICATION FOR FUEL PUMP FC TERMINAL (TACOMA, TUNDRA 3.4L V6 & 4RUNNER) Application ECM Connector No. ECM Terminal No. & Wire Color Tacoma Calif. Emission Vehicles E5 3 (Green/Yellow) Except Calif. Emission Vehicles E7 18 (Green/Yellow) Tundra 3.4L V6 Calif. Emission Vehicles E3 3 (Yellow) Except Calif. Emission Vehicles E5 18 (Yellow) 4Runner E14 3 (Green/Yellow)
4. Check ECM power source circuit. See «ENGINE CONTROL MODULE (ECM) POWER SOURCE CIRCUIT»(ref-3026-S04299435392000051500000). If ECM power source circuit is okay, go to next step. If ECM power source circuit is defective, repair as necessary.
5. Check operation of circuit opening relay. See «CIRCUIT OPENING RELAY»(ref-3026-S38220287942000041700000) under MOTORS & RELAYS. If circuit opening relay operates properly, go to next step. If circuit opening relay is defective, replace circuit opening relay.
6. Remove glove box for access to ECM if not previously done. For illustration of ECM location, see THEORY & OPERATION article. Note ECM terminals. (Scheme 101)- (Scheme 106).
7. Turn ignition on. Using voltmeter, check voltage between body ground and FC terminal at ECM. See «ECM IDENTIFICATION FOR FUEL PUMP FC TERMINAL (TACOMA, TUNDRA 3.4L V6 & 4RUNNER)»(ref-3026-S24058204922000052200000) table. Voltage should be 9-14 volts. If voltage is within specification, go to next step. 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 appropriate wiring diagram in WIRING DIAGRAMS article. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment, near battery. Repair wiring harness or electrical connectors as necessary.
8. Check fuel pump resistance and operation. See «FUEL DELIVERY»(ref-3026-S35804695532000041700000) 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.
9. Check for open in wiring harness and electrical connectors between circuit opening relay and fuel pump, and between fuel pump and body ground. See appropriate wiring diagram in WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary.
10. Check ECM ground circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. NOTE: On 4Runner 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.

Fuel pump control circuit test is not available from manufacturer. If problem exists in fuel pump control circuit, a Diagnostic Trouble Code (DTC) will be stored in Engine Control Module (ECM).

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.

1. If using scan tool, go to next step. If scan tool is not available, go to step 5.
2. Connect scan tool to data link connector No. 3. (Scheme 89) Turn ignition on and then turn scan tool on. Read STA signal display on scan tool with ignition on and with ignition in START position and engine cranking. The STA signal display should read OFF with ignition on and ON with ignition 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 article.
3. Check for open in wiring harness and electrical connectors between ECM and starter relay. See appropriate wiring diagram in WIRING DIAGRAMS article. ECM is located behind glove box. For illustration of ECM location, see THEORY & OPERATION article. Starter relay is located in fuse/relay box at driver's side front corner of engine compartment, near battery.
4. If wiring harness or electrical connector are defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. 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.
5. Remove glove box for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminals. (Scheme 97) Using voltmeter, check voltage between body ground and terminal No. 7 (Black/Red wire) at ECM electrical connector E8 with ignition 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 article.
6. Check for open in wiring harness and electrical connectors between ECM and starter relay. See appropriate wiring diagram in WIRING DIAGRAMS article. Starter relay is located in fuse/relay box at driver's side front corner of engine compartment, near battery.
7. If wiring harness or electrical connector are defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. 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.

Scheme 88

1. If using scan tool, go to next step. If scan tool is not available, go to step 5.
2. Connect scan tool to data link connector No. 3. (Scheme 90)and (Scheme 91). Turn ignition on and then turn scan tool on. Read STA signal display on scan tool with ignition on and with ignition in START position and engine cranking. The STA signal display should read OFF with ignition on and ON with ignition 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 article.
3. Check for open in wiring harness and electrical connectors between ECM and junction connectors J6 and J7. See appropriate wiring diagram in STARTERS article in STARTING & CHARGING SYSTEMS. ECM is located behind glove box. For illustration of ECM location, see THEORY & OPERATION article. Junction connectors J6 and J7 are located behind driver's side of instrument panel, near fuse/relay box. (Scheme 88) NOTE: Junction connectors J6 and J7 may also be referred to as junction connectors J7 and J8 when referring to wiring diagram.
4. If wiring harness or electrical connector are defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See appropriate wiring diagram in WIRING DIAGRAMS 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.
5. Remove glove box for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminals. (Scheme 98) Using voltmeter, check voltage between body ground and STA terminal at ECM with ignition in START position and engine cranking. See «ECM TERMINAL IDENTIFICATION FOR STARTER SIGNAL (CAMRY & CAMRY SOLARA)»(ref-3026-S13677302332000052200000) table. ECM TERMINAL IDENTIFICATION FOR STARTER SIGNAL (CAMRY & CAMRY SOLARA) Application ECM Connector No. ECM Terminal No. & Wire Color Camry E7 (1) 7 (Gray Or Black/Orange) Camry Solara E7 7 (Gray) (1) Gray wire is used on Toyota Motor Corporation (TMC) vehicles and Black/Orange wire is used on Toyota Motor Manufacturing Kentucky (TMMK) vehicles.
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 article.
7. Check for open in wiring harness and electrical connectors between ECM and junction connectors J6 and J7. See appropriate wiring diagram in STARTERS article in STARTING & CHARGING SYSTEMS. Junction connectors J6 and J7 are located behind driver's side of instrument panel, near fuse/relay box. (Scheme 88) NOTE: Junction connectors J6 and J7 may also be referred to as junction connectors J7 and J8 when referring to wiring diagram.
8. If wiring harness or electrical connector are defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See appropriate wiring diagram in WIRING DIAGRAMS 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.

1. If using scan tool, go to next step. If scan tool is not available, go to step 5.
2. Connect scan tool to data link connector No. 3. (Scheme 92) Turn ignition on and then turn scan tool on. Read STA signal display on scan tool with ignition on and with ignition in START position and engine cranking. The STA signal display should read OFF with ignition on and ON with ignition 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 article.
3. Check for open in wiring harness and electrical connectors between ECM and starter relay. See appropriate wiring diagram in STARTERS article in STARTING & CHARGING SYSTEMS. ECM is located behind glove box. For illustration of ECM location, see THEORY & OPERATION article. Starter relay is located in fuse/relay box at driver's side front corner of engine compartment, near battery.
4. If wiring harness or electrical connector are defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. 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.
5. Remove glove box for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminals. (Scheme 99) Using voltmeter, check voltage between body ground and terminal No. 17 (Black/Red wire) at ECM electrical connector E8 with ignition in START position and engine cranking. This is the STA terminal at ECM.
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 article.
7. Check for open in wiring harness and electrical connectors between ECM and starter relay. See appropriate wiring diagram in STARTERS article in STARTING & CHARGING SYSTEMS. Starter relay is located in fuse/relay box at driver's side front corner of engine compartment, near battery.
8. If wiring harness or electrical connector are defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. 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.

1. If using scan tool, go to next step. If scan tool is not available, go to step 5.
2. Connect scan tool to data link connector No. 3. (Scheme 93) Turn ignition on and then turn scan tool on. Read STA signal display on scan tool with ignition on and with ignition in START position and engine cranking. The STA signal display should read OFF with ignition on and ON with ignition 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 article.
3. Check for open in wiring harness and electrical connectors between ECM and park/neutral position switch. See appropriate wiring diagram in WIRING DIAGRAMS article. ECM is located behind glove box, just above passenger's side lower instrument panel cover. For illustration of ECM location, see THEORY & OPERATION article. Park/neutral position switch is located on side of transaxle.
4. If wiring harness or electrical connector are defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. 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.
5. Remove passenger's side lower instrument panel cover for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM terminals. (Scheme 100) Using voltmeter, check voltage between body ground and terminal No. 7 (Gray wire) at ECM electrical connector E8 with ignition in START position and engine cranking. This is the STA terminal at ECM.
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 article.
7. Check for open in wiring harness and electrical connectors between ECM and park/neutral position switch. See appropriate wiring diagram in WIRING DIAGRAMS article. Park/neutral position switch is located on side of transaxle.
8. If wiring harness or electrical connector are defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. 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.

Scheme 89

Scheme 90

Scheme 91

Scheme 92

Scheme 93

Scheme 94

Scheme 95

Scheme 96

1. If using scan tool, go to next step. If scan tool is not available, go to step 5.
2. Connect scan tool to data link connector No. 3. (Scheme 94)- (Scheme 96). Turn ignition on and then turn scan tool on. Read STA signal display on scan tool with ignition on and with ignition in START position and engine cranking. The STA signal display should read OFF with ignition on and ON with ignition 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 article.
3. Check for open in wiring harness and electrical connectors between ECM and park/neutral position switch (A/T models) or clutch start switch (M/T models). See appropriate wiring diagram in WIRING DIAGRAMS article. ECM is located behind glove box. For illustration of ECM location, see THEORY & OPERATION article. Park/neutral position switch is located on side of transmission. Clutch start switch is located near top of clutch pedal.
4. If wiring harness or electrical connector are defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. NOTE: On 4Runner 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.
5. Remove glove box for access to ECM. For illustration of ECM location, see THEORY & OPERATION article. Note ECM electrical connector terminals. (Scheme 101)- (Scheme 106). Using voltmeter, check voltage between body ground and STA terminal at ECM with ignition in START position and engine cranking. See «ECM TERMINAL IDENTIFICATION FOR STARTER SIGNAL (TACOMA, TUNDRA & 4RUNNER)»(ref-3026-S23753803752000052200000) table. ECM IDENTIFICATION FOR STARTER SIGNAL (TACOMA, TUNDRA & 4RUNNER) Application ECM Connector No. ECM Terminal No. & Wire Color Tacoma Calif. Emission Vehicles E5 7 (Black/White) Except Calif. Emission Vehicles E8 13 (Black/White) Tundra 3.4L V6 Calif. Emission Vehicles E3 7 (Black/White) Except Calif. Emission Vehicles E6 13 (Black/White) 4.7L V8 E4 17 (Black/White) 4Runner E14 7 (Black/White)
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 article.
7. Check for open in wiring harness and electrical connectors between ECM and park/neutral position switch (A/T models) or clutch start switch (M/T models). See appropriate wiring diagram in WIRING DIAGRAMS article. Park/neutral position switch is located on side of transmission. Clutch start switch is located near top of clutch pedal.
8. If wiring harness or electrical connector are defective, repair as necessary. If wiring harness and electrical connectors are okay, check ECM ground circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. If ECM ground circuit is defective, repair ground circuit as necessary. If ECM ground circuit is okay, replace ECM. NOTE: On 4Runner 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.

Power & Ground Circuits

For testing of Engine Control Module (ECM) power and ground circuits, see ENGINE CONTROL MODULE (ECM) 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 97)- (Scheme 106).

Scheme 97

Scheme 98

Scheme 99

Scheme 100

Scheme 101

Scheme 102

Scheme 103

Scheme 104

Scheme 105

Scheme 106

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

AIR/FUEL (A/F) SENSOR

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

Avalon, Camry Calif. Emission Vehicles, Camry Solara Calif. Emission Vehicles & Sienna Calif. Emission Vehicles

1. Two heated A/F sensors are used, one on each exhaust manifold. Heated A/F sensor on rear (firewall side) exhaust manifold may also be referred to as bank No. 1 sensor No. 1. Heated A/F sensor on front (radiator side) exhaust manifold may also be referred to as bank No. 2 sensor No. 1.
2. To check heater resistance on A/F sensor, disconnect electrical connector at A/F sensor. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 107)and (Scheme 108). Replace A/F sensor if resistance is not.8-1.4 ohms at 68°F (20°C) and 1.8-3.2 ohms at 1472°F (800°C).
3. 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 RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Scheme 107

Scheme 108

Tacoma Calif. Emission Vehicles, Tundra 3.4L V6 Calif. Emission Vehicles & 4Runner Calif. Emission Vehicles

1. Heated A/F is located on exhaust pipe in front of catalytic converter. Heated A/F sensor may also be referred to as bank No. 1 sensor No. 1.
2. To check heater resistance on A/F sensor, disconnect electrical connector at A/F sensor. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 109) Replace A/F sensor if resistance is not.8-1.4 ohms at 68°F (20°C) and 1.8-3.2 ohms at 1472°F (800°C).
3. 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 RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Scheme 109

AIRFLOW METER

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

Scheme 110

Scheme 111

1. Turn ignition off. Disconnect electrical connector at airflow meter. Airflow meter is bolted to top side of air intake hose, near upper cap on air cleaner assembly. Remove airflow meter and note airflow meter terminal identification. (Scheme 110)
2. Using ohmmeter, check resistance between terminals E2 and THA. Resistance should be within specification in relation to the temperature. See «AIRFLOW METER RESISTANCE»(ref-3026-S28931305912000041700000) table. Replace airflow meter if resistance is not within specification.
3. To test airflow meter operation, ensure electrical connector is installed on airflow meter. Connect voltmeter leads to proper terminals on airflow meter with electrical connector installed. (Scheme 111)
4. Turn ignition on. Apply air into airflow meter and note voltage reading. (Scheme 111) While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate. Remove voltmeter. Reinstall airflow meter.

Scheme 112

Scheme 113

1. Turn ignition off. Disconnect electrical connector at airflow meter. Airflow meter is bolted to side of air intake hose, near upper cap on air cleaner assembly. Remove airflow meter with gasket and note airflow meter terminal identification. (Scheme 112)
2. Using ohmmeter, check resistance between terminals E2 and THA. Resistance should be within specification in relation to the temperature. See «AIRFLOW METER RESISTANCE»(ref-3026-S28931305912000041700000) table. Replace airflow meter if resistance is not within specification.
3. To test airflow meter operation, ensure electrical connector is installed on airflow meter. Connect voltmeter leads to proper terminals on airflow meter with electrical connector installed. (Scheme 113)
4. Turn ignition on. Apply air into airflow meter and note voltage reading. (Scheme 113) While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate. Remove voltmeter. Reinstall airflow meter using NEW gasket.

Scheme 114

Scheme 115

1. Turn ignition off. Disconnect electrical connector at airflow meter. Airflow meter is bolted to top side of air intake hose, near upper cap on air cleaner assembly. Remove airflow meter and note airflow meter terminal identification. (Scheme 114)
2. Using ohmmeter, check resistance between terminals E2 and THA. Resistance should be within specification in relation to the temperature. See «AIRFLOW METER RESISTANCE»(ref-3026-S28931305912000041700000) table. Replace airflow meter if resistance is not within specification.
3. To test airflow meter operation, ensure electrical connector is installed on airflow meter. Connect voltmeter leads to proper terminals on airflow meter with electrical connector installed. (Scheme 115)
4. Turn ignition on. Apply air into airflow meter and note voltage reading. (Scheme 115) While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate. Remove voltmeter. Reinstall airflow meter.

Scheme 116

1. Turn ignition off. Disconnect electrical connector at airflow meter. Airflow meter is bolted to air intake hose, near air cleaner assembly. Remove airflow meter with "O" ring (if equipped) and note airflow meter terminal identification. (Scheme 110)
2. Using ohmmeter, check resistance between terminals E2 and THA. Resistance should be within specification in relation to the temperature. See «AIRFLOW METER RESISTANCE»(ref-3026-S28931305912000041700000) table. Replace airflow meter if resistance is not within specification.
3. To test airflow meter operation, ensure electrical connector is installed on airflow meter. Connect voltmeter leads to proper terminals on airflow meter with electrical connector installed. (Scheme 116)
4. Turn ignition on. Apply air into airflow meter and note voltage reading. (Scheme 116) While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate. Remove voltmeter. Reinstall airflow meter using "O" ring (if equipped).

AIRFLOW METER RESISTANCE

Scheme 117

1. Disconnect electrical connector at brakelight switch. Brakelight switch is located near top of the brake pedal. Note terminal identification on brakelight switch. (Scheme 117)
2. On models without cruise control, using ohmmeter, check that no continuity exists between terminals No. 1 and 2 with brake pedal released. Check that continuity exists between terminals No. 1 and 2 with brake pedal depressed. Adjust or replace brakelight switch if operation is not as described.
3. On models with cruise control, using ohmmeter, check that no continuity exists between terminals No. 1 and 2 with brake pedal released. Check that continuity exists between terminals No. 1 and 2 with brake pedal depressed.
4. Check that no continuity exists between terminals No. 3 and 4 with brake pedal depressed. Check that continuity exists between terminals No. 3 and 4 brake pedal released. Adjust or replace brakelight switch if operation is not as described.

Scheme 118

1. Disconnect electrical connector at brakelight switch. Brakelight switch is located near top of brake pedal. Note terminal identification on the brakelight switch. (Scheme 118)
2. Using ohmmeter, check that continuity exists between terminals No. 1 and 2 with brake pedal depressed. Check that no continuity exists between terminals No. 1 and 2 with brake pedal released.
3. Check that no continuity exists between terminals No. 3 and 4 with brake pedal depressed. Check that continuity exists between terminals No. 3 and 4 with brake pedal released. Adjust or replace brakelight switch if operation is not as described.

CAMSHAFT POSITION SENSOR

For testing camshaft position sensor, see CAMSHAFT POSITION SENSOR RESISTANCE under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article.

CRANKSHAFT POSITION SENSOR

For testing crankshaft position sensor, see CRANKSHAFT POSITION SENSOR RESISTANCE under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article.

Camry & Camry Solara

1. Manufacturer recommends removing throttle body for access to EGR gas temperature sensor. See THROTTLE BODY under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. Remove EGR gas temperature sensor. EGR gas temperature sensor is screwed into bottom of pipe that EGR valve is mounted on.
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. WARNING: Use care when heating oil. Hot oil is extremely flammable.
3. Heat oil and note resistance at specified temperature. See «EGR GAS TEMPERATURE SENSOR RESISTANCE»(ref-3026-S32948347352000041700000) table. Replace EGR gas temperature sensor if resistance is not within specification. Reinstall EGR gas temperature sensor. EGR GAS TEMPERATURE SENSOR RESISTANCE Temperature °F (°C) Ohms 122 (50) 64,000-97,000 212 (100) 11,000-16,000 302 (150) 2000-4000

For testing of EGR position sensor, see EGR POSITION SENSOR under EMISSION SYSTEMS & SUB-SYSTEMS.

Avalon, Camry, Camry Solara & Sienna

1. Ensure ignition is off. Note location of ECT sensor. See «ENGINE COOLANT TEMPERATURE (ECT) SENSOR LOCATION»(ref-3026-S25197023582000041700000) table. Remove ECT sensor. See ENGINE COOLANT TEMPERATURE (ECT) SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 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 119) Replace ECT sensor if resistance is not within specification.
3. Using NEW gasket, install ECT sensor. Tighten ECT sensor to 15 ft. lbs. (20 N.m). Fill cooling system.

1. Note location of ECT sensor. See «ENGINE COOLANT TEMPERATURE (ECT) SENSOR LOCATION»(ref-3026-S25197023582000041700000) table. Manufacturer recommends removing throttle body for access to ECT sensor. Remove ECT sensor. See ENGINE COOLANT TEMPERATURE (ECT) SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 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 119) Replace ECT sensor if resistance is not within specification.
3. Using NEW gasket, install ECT sensor. Tighten ECT sensor to 15 ft. lbs. (20 N.m). Install throttle body. Fill cooling system.

1. Note location of ECT sensor. See «ENGINE COOLANT TEMPERATURE (ECT) SENSOR LOCATION»(ref-3026-S25197023582000041700000) table. Manufacturer recommends removing upper timing belt cover and fuel crossover pipe for access to ECT sensor. Remove ECT sensor. See ENGINE COOLANT TEMPERATURE (ECT) SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 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 119) Replace ECT sensor if resistance is not within specification.
3. Using NEW gasket, install ECT sensor. Tighten ECT sensor to 15 ft. lbs. (20 N.m). Fill cooling system.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR LOCATION

Scheme 119

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

Scheme 120

1. Air/Fuel (A/F) sensor is used on each exhaust manifold and heated oxygen sensor is used on exhaust pipe behind catalytic converter. For testing of A/F sensor, see «AIR/FUEL (A/F) SENSOR»(ref-3026-S32418189842000041700000) under ENGINE SENSORS & SWITCHES. Heated oxygen sensor on exhaust pipe behind catalytic converter may also be referred to as bank No. 1 sensor No. 2.
2. To test heater on heated oxygen sensor, disconnect electrical connector for heated oxygen sensor and note heated oxygen sensor terminals. (Scheme 120) Electrical connector for heated oxygen sensor is located below passenger's side front seat, near center console and contains a Dark Gray 4-pin electrical connector.
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 120) 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).
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 RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

1. On Calif. emission vehicles, a heated oxygen sensor is used on exhaust pipe behind catalytic converter and Air/Fuel (A/F) sensor is used on each exhaust manifold. For testing of A/F sensor, see «AIR/FUEL (A/F) SENSOR»(ref-3026-S32418189842000041700000) under ENGINE SENSORS & SWITCHES. On except Calif. emission vehicles, heated oxygen sensor is used on each exhaust manifold and on exhaust pipe behind catalytic converter.
2. Heated oxygen sensor on rear (firewall side) exhaust manifold may also be referred to as bank No. 1 sensor No. 1. Heated oxygen sensor on front (radiator side) exhaust manifold may also be referred to as bank No. 2 sensor No. 1. Heated oxygen sensor on the exhaust pipe behind catalytic converter may also be referred to as bank No. 1 sensor No. 2.
3. To test heater on heated oxygen sensor, disconnect electrical connector at appropriate heated oxygen sensor and note heated oxygen sensor terminals. (Scheme 121)and (Scheme 122). Electrical connector for heated oxygen sensor on exhaust pipe behind catalytic converter is located below driver's side front seat, below carpet near center console and contains a Dark Gray 4-pin electrical connector.
4. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 121)and (Scheme 122). 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).
5. 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 RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Scheme 121

Scheme 122

1. Four heated oxygen sensors are used, one on each exhaust manifold, and one on each exhaust pipe behind catalytic converter. On driver's side, heated oxygen sensor on exhaust manifold may also be referred to as bank No. 1 sensor No. 1 and heated oxygen sensor on exhaust pipe behind catalytic converter may also be referred to as bank No. 1 sensor No. 2. On passenger's side, heated oxygen sensor on exhaust manifold may also be referred to as bank No. 2 sensor No. 1 and heated oxygen sensor on exhaust pipe behind catalytic converter may also be referred to as bank No. 2 sensor No. 2.
2. To test heater on heated oxygen sensor, disconnect electrical connector at appropriate heated oxygen sensor and note heated oxygen sensor terminals. (Scheme 123)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 123) On Land Cruiser, replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C). On Tundra 4.7L V8, 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).
4. On all models, 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 RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Scheme 123

1. On Calif. emission vehicles, a heated oxygen sensor is used on exhaust pipe behind catalytic converter and Air/Fuel (A/F) sensor is used on each exhaust manifold. For testing of A/F sensor, see «AIR/FUEL (A/F) SENSOR»(ref-3026-S32418189842000041700000) under ENGINE SENSORS & SWITCHES. Heated oxygen sensor on exhaust pipe behind catalytic converter may also be referred to as bank No. 1 sensor No. 2.
2. On except Calif. emission vehicles, heated oxygen sensor is used on each exhaust manifold and on exhaust pipe behind catalytic converter. Heated oxygen sensor on rear (firewall side) exhaust manifold may also be referred to as bank No. 1 sensor No. 1. Heated oxygen sensor on front (radiator side) exhaust manifold may also be referred to as bank No. 2 sensor No. 1. Heated oxygen sensor on exhaust pipe behind catalytic converter may also be referred to as bank No. 1 sensor No. 2.
3. To test heater on heated oxygen sensor, disconnect electrical connector at appropriate heated oxygen sensor and note heated oxygen sensor terminals. (Scheme 124)and (Scheme 125). Electrical connector for heated oxygen sensor on exhaust pipe behind catalytic converter is located below passenger's side front seat, underneath the carpet and contains a Dark Gray 4-pin electrical connector.
4. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 124)and (Scheme 125). Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C).
5. 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 RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Scheme 124

Scheme 125

1. On Calif. emission vehicles, a heated oxygen sensor is used on exhaust pipe behind catalytic converter and Air/Fuel (A/F) sensor is used on exhaust pipe in front of catalytic converter. For testing of A/F sensor, see «AIR/FUEL (A/F) SENSOR»(ref-3026-S32418189842000041700000) under ENGINE SENSORS & SWITCHES. Heated oxygen sensor exhaust pipe behind catalytic converter may also be referred to as bank No. 1 sensor No. 2.
2. On except Calif. emission vehicles, a heated oxygen sensor is used on exhaust pipe in front of catalytic converter and one on exhaust pipe behind catalytic converter. Heated oxygen sensor on exhaust pipe in front of catalytic converter may also be referred to as bank No. 1 sensor No. 1. Heated oxygen sensor exhaust pipe behind catalytic converter may also be referred to as bank No. 1 sensor No. 2.
3. To test heater on heated oxygen sensor, disconnect electrical connector at appropriate heated oxygen sensor and note heated oxygen sensor terminals. (Scheme 126)
4. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 126) 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).
5. 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 RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Scheme 126

Avalon, Camry, Camry Solara, Sienna, Tacoma, Tundra 3.4L V6 & 4Runner

1. Knock sensors No. 1 and 2 are located below intake manifold on cylinder block. (Scheme 127)and (Scheme 128). Manufacturer lists testing procedure with knock sensor removed from cylinder block before testing. Remove knock sensor. See KNOCK SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
2. Using ohmmeter, check that no continuity exists between electrical terminal on knock sensor and body of knock sensor. Replace knock sensor if continuity exists.

Scheme 127

Scheme 128

1. Knock sensors No. 1 and 2 are located below intake manifold on cylinder block. (Scheme 129) Remove intake manifolds for access to knock sensor. See KNOCK SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article for removal of intake manifolds.
2. Disconnect electrical connector at knock sensor. Using ohmmeter, check that no continuity exists between electrical terminal on knock sensor and body of knock sensor. Replace knock sensor if continuity exists.

Scheme 129

A/T Models

1. Disconnect electrical connector at PNP switch. PNP switch is mounted on side of transmission/transaxle. Note terminal identification. (Scheme 130)and (Scheme 131).
2. Using ohmmeter, check for continuity between specified terminals with shift lever in proper positions. See «PARK/NEUTRAL POSITION SWITCH SPECIFICATIONS»(ref-3026-S11794457082000041700000) table. If proper continuity cannot obtained, adjust or replace PNP switch as necessary.

PARK/NEUTRAL POSITION SWITCH SPECIFICATIONS

Scheme 130

Scheme 131

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

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

1. Ensure ignition is off. Disconnect electrical connector at Throttle Position (TP) sensor mounted on side of throttle body. Note terminal identification on TP sensor. (Scheme 132)- (Scheme 135).
2. Apply vacuum to throttle opener. Using ohmmeter, check resistance between specified terminals in relation to throttle position. See «THROTTLE POSITION SENSOR RESISTANCE»(ref-3026-S41068346422000041700000) table. Replace components as necessary if resistance is not within specification.

THROTTLE POSITION SENSOR RESISTANCE (1)

Scheme 132

Scheme 133

Scheme 134

Scheme 135

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

VAPOR PRESSURE SENSOR

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

VVT sensor may also be referred to as camshaft position sensor. For testing of camshaft position sensor, see CAMSHAFT POSITION SENSOR RESISTANCE under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article.

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

1. Vehicle speed sensor is located on transaxle. (Scheme 136) 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 137)
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 137)
3. While rotating vehicle speed sensor shaft, ensure voltage changes from zero volts to at least 11 volts. Voltage should change 4 times per revolution of the shaft. Replace vehicle speed sensor if voltage does not change as specified. Remove test equipment.

Scheme 136

Scheme 137

Vehicle speed sensor is located on transmission. (Scheme 138) Testing information is not available from manufacturer.

Scheme 138

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

Scheme 139

Scheme 140

Scheme 141

1. Vehicle speed sensor is mounted near rear of transmission or transfer case and contains a 3-pin electrical connector. Electrical connector contains Blue, Green/Red and Pink wires.
2. Connect voltmeter positive lead to terminal No. 3 (outer terminal) and negative lead to terminal No. 2 (center terminal) on vehicle speed sensor. (Scheme 139)- (Scheme 141).
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 139)- (Scheme 141).
4. While rotating vehicle speed sensor shaft, ensure voltage changes from zero volts to at least 11 volts. Voltage should change 4 times per revolution of the shaft. Replace vehicle speed sensor if voltage does not change as specified. Remove test equipment.

Tundra

1. Vehicle speed sensor is mounted near rear of transmission or transfer case and contains a 3-pin electrical connector. Electrical connector contains Blue/Yellow, Black/Yellow and Pink/Blue wires. 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 137)
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 137)
3. While rotating vehicle speed sensor shaft, ensure voltage changes from zero volts to at least 11 volts. Voltage should change 4 times per revolution of the shaft. Replace vehicle speed sensor if voltage does not change as specified. Remove test equipment.

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

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

See FUEL PUMP ELECTRONIC CONTROL UNIT (LAND CRUISER) under FUEL DELIVERY under FUEL SYSTEMS.

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

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 142

1. Remove A/F heater relay. See «A/F HEATER RELAY LOCATION»(ref-3026-S37122893442000041700000) table. A/F HEATER RELAY LOCATION Application Location Avalon In Fuse/Relay Box At Driver's Side Front Corner Of Engine Compartment, Near Battery & Air Cleaner Camry & Camry Solara In Small Fuse/Relay Box At Driver's Side Front Corner Of Engine Compartment, In Front Of Battery
2. To test A/F heater relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on A/F heater relay. (Scheme 142)
3. To test A/F heater relay operation, apply battery voltage and ground to A/F heater relay and use ohmmeter to check continuity between specified terminals on A/F heater relay. (Scheme 142) Replace A/F heater relay if defective.

Sienna Calif. Emission Vehicle

A/F heater relay is located near ECM behind passenger's side of instrument panel and contains a 4-pin connector. (Scheme 143) Testing information is not available from manufacturer. It may be necessary to consult wiring diagram for A/F heater relay testing. See appropriate wiring diagram in WIRING DIAGRAMS article.

Scheme 143

CIRCUIT OPENING RELAY

Note. Circuit opening relay is used on all models except Land Cruiser.

1. Ensure ignition is off. Remove circuit opening relay. See «CIRCUIT OPENING RELAY LOCATION»(ref-3026-S20081913402000041700000) table. (Scheme 144)- (Scheme 150). CIRCUIT OPENING RELAY LOCATION (1) Application Location Avalon Top Corner Of Relay Box Behind Driver's Side Kick Panel Camry, Camry Solara & Sienna In Fuse/Relay Box At Driver's Side Front Corner Of Engine Compartment, Near Battery & Air Cleaner Tacoma Behind Lower Instrument Panel Cover, Next To Driver's Side Of Steering Column Tundra In Fuse/Relay Box At Driver's Side Front Corner Of Engine Compartment, Next To Battery 4Runner Below Right Corner Of Fuse/Relay Box Behind Lower Instrument Panel Cover At Driver's Side Of Instrument Panel To Left Of Steering Column, Just Above Hood Release Lever (1) Circuit opening relay may be marked as CIR OPN relay in the relay box.
2. To test circuit opening relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on circuit opening relay. see scheme 73- (Scheme 153).
3. To test circuit opening relay operation, apply battery voltage and ground to circuit opening relay and use ohmmeter to check continuity between specified terminals on circuit opening relay. see scheme 73- (Scheme 153). Replace circuit opening relay if defective.

Scheme 144

Scheme 145

Scheme 146

Scheme 147

Scheme 148

Scheme 149

Scheme 150

Scheme 151

Scheme 152

Scheme 153

EFI MAIN RELAY

Note. EFI main relay is used on all models and may also be referred to as EFI relay.

1. Ensure ignition is off. Remove EFI main relay from fuse/relay box at driver's side front corner of engine compartment, near battery.
2. To test EFI main relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on EFI main relay. see scheme 73- (Scheme 154).
3. To test EFI main relay operation, apply battery voltage and ground to EFI main relay and use ohmmeter to check continuity between specified terminals on EFI main relay. see scheme 73- (Scheme 154). Replace EFI main relay if defective.

Scheme 154

1. Ensure ignition is off. Remove fuel pump relay from relay box at driver's side front corner of engine compartment, next to battery. (Scheme 149)
2. To test fuel pump relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on fuel pump relay. (Scheme 155)
3. To test fuel pump relay operation, apply battery voltage and ground to fuel pump relay and use ohmmeter to check continuity between specified terminals on fuel pump relay. (Scheme 155) Replace fuel pump relay if defective.

Scheme 155

IG2 RELAY

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

1. Ensure ignition is off. Remove IG2 relay from fuse/relay box at driver's side front corner of engine compartment, next to battery.
2. To test IG2 relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on IG2 relay. see scheme 79
3. To test IG2 relay operation, apply battery voltage and ground to IG2 relay relay and use ohmmeter to check continuity between specified terminals on IG2 relay relay. see scheme 79 Replace IG2 relay relay if defective.

See CIRCUIT OPENING RELAY under MOTORS & RELAYS.

See EFI MAIN RELAY under MOTORS & RELAYS.

Fuel Pump Electronic Control Unit (Land Cruiser)

Fuel pump Electronic Control Unit (ECU) is located behind inner panel, just behind driver's side rear wheelwell. (Scheme 156) Testing information is not available from manufacturer. If problem exists with fuel pump ECU or wiring circuit, a Diagnostic Trouble Code (DTC) P1200 will be stored in Engine Control Module (ECM). See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Scheme 156

Fuel Pump Relay (Tundra 4.7L V8)

See FUEL PUMP RELAY under MOTORS & RELAYS.

Scheme 157

1. Fuel pump resistor is located at driver's side front corner of engine compartment, near end of fuse/relay box. (Scheme 157) Manufacturer lists testing procedure with fuel pump resistor removed. Disconnect electrical connector at fuel pump resistor.
2. Remove bolt and fuel pump resistor. Using ohmmeter, check resistance between electrical terminals on fuel pump resistor. Replace fuel pump resistor if resistance is not.70-.76 ohms at 68°F (20°C). Reinstall fuel pump resistor.

Fuel Pump Switch (Land Cruiser)

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

1. Fuel pump switch is located on driver's side of instrument panel and contains a reset switch. (Scheme 158) Disconnect electrical connector at fuel pump switch. It may be necessary to remove carpet and fuel pump switch for access to electrical connector.
2. Using ohmmeter, check that no continuity exists between electrical terminals on fuel pump switch with reset switch in OFF position. Check that continuity exists between electrical terminals on fuel pump switch with reset switch in ON position. Replace fuel pump switch if defective. Ensure reset switch is in the ON position for fuel pump operation.

Scheme 158

Fuel Pump Pressure

For fuel pump pressure testing, see FUEL PRESSURE under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article.

Fuel Cut System

1. On Avalon, Camry, Camry Solara and Sienna, remove "V" bank cover on top of engine for access to fuel injectors. (Scheme 82), (Scheme 83) and (Scheme 84).
2. On all models, connect scan tool to data link connector No. 3. (Scheme 89)- (Scheme 96). Scan tool is used to read engine RPM. Start engine and warm engine to normal operating temperature.
3. Ensure A/C is off. Gradually increase engine RPM to specified RPM. See «FUEL CUT SYSTEM TESTING SPEED»(ref-3026-S40415309382000041700000) table. FUEL CUT SYSTEM TESTING SPEED Application Engine RPM Avalon, Camry, Camry Solara, Sienna, Tacoma, Tundra 3.4L V6 & 4Runner 3500 Land Cruiser & Tundra 4.7L V8 2500
4. 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).
5. Ensure fuel return RPM is within specification. See «FUEL CUT SYSTEM SPECIFICATIONS»(ref-3026-S14041970112000041700000) table. Shut engine off. Remove scan tool.

FUEL CUT SYSTEM SPECIFICATIONS (1)

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS - V6 & V8 article.
2. Turn ignition off. Apply parking brake and place transaxle in Neutral. Ensure A/C is off. Install Jumper Wire (SST 09843-18020) between terminals TE1 and E1 on data link connector No. 1. Data link connector No. 1 is located in the engine compartment on end of air intake chamber at passenger's side of engine. (Scheme 161)
3. Start engine and note engine RPM. Engine should increase to 1000 RPM for 5 seconds and then return to idle speed. If engine speed is not as specified, test IAC valve operation. Go to next step. If engine speed is as specified, remove jumper wire. Turn ignition off.
4. To test IAC valve operation, remove IAC valve from throttle body. See THROTTLE BODY under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. Check that valve on inside of IAC valve is half open. (Scheme 170) Reinstall electrical connector on IAC valve.
5. Turn ignition on. Check that valve on inside of IAC valve moves to fully closed position, fully open position and then returns to half open position.
6. If IAC valve operates properly, it may be necessary to check wiring circuit between Engine Control Module (ECM) and IAC valve for intermittent problem. ECM is located behind glove box. If wiring circuit is okay, but idle problem still exists, the air assist system may be defective. For testing of air assist system, see «AIR ASSIST SYSTEM»(ref-3026-S17292960852000041700000). If IAC valve does not operate properly, check wiring circuit between Engine Control Module (ECM) and IAC valve. ECM is located behind glove box. If wiring circuit is okay, replace IAC valve. See «ECM LOCATION»(ref-3026-S37281478102000041700000) table. See appropriate wiring diagram in WIRING DIAGRAMS article.

Camry, Camry Solara, Sienna, Tacoma, Tundra 3.4L V6 & 4Runner

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS - V6 & V8 article.
2. Turn ignition off. Apply parking brake and place transmission/transaxle in Neutral. Ensure A/C is off. Install Jumper Wire (SST 09843-18020) between terminals TE1 and E1 on data link connector No. 1 located in the engine compartment. (Scheme 162)- (Scheme 166). See «DATA LINK CONNECTOR NO. 1 LOCATION»(ref-3026-S41743587622000041700000) table. DATA LINK CONNECTOR NO. 1 LOCATION Application Location Camry On End Of Air Intake Chamber At Passenger's Side Of Engine Camry Solara Passenger's Side Of Engine Compartment, Near Strut Tower Sienna On Engine Mount Bracket Near Passenger's Side Strut Tower Tacoma, Tundra & 4Runner Center Of Air Intake Chamber At Driver's Side Of Engine
3. Start engine and note engine RPM. Engine should increase to 1000 RPM for 5 seconds and then return to idle speed. If engine speed is not as specified, test IAC valve resistance and IAC valve operation. Go to next step. If engine speed is as specified, remove jumper wire. Turn ignition off.
4. To test IAC valve resistance, ensure ignition is off. Disconnect electrical connector at IAC valve. IAC valve is located on lower area of throttle body. Using ohmmeter, checking resistance between +B terminal and each remaining terminal on IAC valve. (Scheme 167)- (Scheme 169).
5. Replace IAC valve if resistance is not within specification. See «IAC VALVE RESISTANCE»(ref-3026-S19587804942000041700000) table. IAC VALVE RESISTANCE Application Ohms Camry Cold (1) 17.0-25.0 Hot (2) 21.5-29.5 Camry Solara & Sienna Cold (1) 17.0-24.5 Hot (2) 21.5-28.5 Tacoma, Tundra & 4Runner Cold (1) 17.0-25.0 Hot (2) 21.5-29.5 (1) Cold is with temperature of 14-122°F (-10-50°C). (2) Hot is with temperature of 122-212°F (50-100°C).
6. To test IAC valve operation, remove IAC valve from throttle body. See IDLE AIR CONROL (IAC) VALVE under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. Apply battery voltage to +B terminal on IAC valve. Apply battery ground to proper terminal and ensure valve opens and closes. (Scheme 171)and (Scheme 172). Replace IAC valve if defective.
7. If IAC valve resistance is within specification and operates properly, check wiring circuit between Engine Control Module (ECM) and IAC valve. See «ECM LOCATION»(ref-3026-S37281478102000041700000) table. See appropriate wiring diagram in WIRING DIAGRAMS article. NOTE: If all components and wiring circuit are okay, but idle problem still exists, the air assist system may be defective. For testing of air assist system, see «AIR ASSIST SYSTEM»(ref-3026-S17292960852000041700000).

ECM LOCATION

Scheme 159

Scheme 160

Scheme 161

Scheme 162

Scheme 163

Scheme 164

Scheme 165

Scheme 166

Scheme 167

Scheme 168

Scheme 169

Scheme 170

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS - V6 & V8 article.
2. Turn ignition off. Apply parking brake and place transmission/transaxle in Neutral. Ensure A/C is off. Install Jumper Wire (SST 09843-18020) between terminals TE1 and E1 on data link connector No. 1 located in the engine compartment. (Scheme 161)- (Scheme 166). See «DATA LINK CONNECTOR NO. 1 LOCATION»(ref-3026-S31091207762000041700000) table. DATA LINK CONNECTOR NO. 1 LOCATION Application Location Avalon & Camry On End Of Air Intake Chamber At Passenger's Side Of Engine Camry Solara Passenger's Side Of Engine Compartment, Near Strut Tower Sienna On Engine Mount Bracket Near Passenger's Side Strut Tower Tacoma, Tundra & 4Runner Center Of Air Intake Chamber At Driver's Side Of Engine
3. Start engine and note engine RPM. After engine RPM is kept at 900-1300 RPM for 10 seconds, ensure engine returns to idle speed. Turn ignition off.
4. On Avalon, Camry, Camry Solara and Sienna, disconnect air assist hose from air pipe. (Scheme 173)- (Scheme 175). Air assist hose fits between IAC valve and air pipe. Place plug on end of air pipe and air assist hose. (Scheme 173)- (Scheme 175). Go to step 6.
5. On Tacoma, Tundra and 4Runner, disconnect air assist hose from IAC valve. (Scheme 176) Place plug on end of air assist hose. (Scheme 176) Go to next step.
6. On all models, start engine and note idle speed. Idle speed should be 500 RPM or less which may cause the engine to stall. Turn ignition off.
7. If idle speed is not 500 RPM or less, check for air leak between air assist hoses, air pipe and fuel injectors. Remove plug(s) and jumper wire. Reconnect air assist hose.

Scheme 171

Scheme 172

Scheme 173

Scheme 174

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

Scheme 175

Scheme 176

Scheme 177

Scheme 178

Scheme 179

1. On Land Cruiser, remove intake manifold cover located on top of engine for access to throttle body. On Tundra, remove throttle body cover for access to throttle body. On all models, ensure throttle cable and throttle lever on throttle body move smoothly. Note location of throttle control motor on throttle body. (Scheme 177)
2. To check throttle control motor operation, turn ignition on. Rotate throttle lever on throttle body to full throttle while listing for operating sound at throttle control motor and that no grinding noise is heard at throttle control motor and throttle body. Throttle lever will also rotate accelerator pedal position sensor.
3. If throttle control motor operating sound is heard, go to next step. If throttle control motor operating sound is not heard, throttle control motor, wiring harness or Engine Control Motor (ECM) may be defective. On Land Cruiser, ECM is located above glove box, near passenger's side of instrument panel. On Tundra, ECM is located behind glove box and air inlet duct. On all models, for illustration of ECM location, see THEORY & OPERATION article. Go to step 12 for testing of throttle control motor.
4. To test operation of accelerator pedal position sensor, scan tool may be used or voltmeter may be used. If using scan tool, go to next step. If using voltmeter, go to step 8.
5. Connect scan tool to data link connector No. 3. (Scheme 92)and (Scheme 95). Scan tool is used to read throttle valve opening which is displayed as a percentage. Ensure Malfunction Indicator Light (MIL) on instrument panel is not illuminated. If MIL is not illuminated, go to next step. If MIL is illuminated, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.
6. Rotate throttle lever on throttle body to full throttle while reading throttle valve opening on scan tool which is accessed by THROTTLE POS under CURRENT DATA. Throttle lever will also rotate accelerator pedal position sensor. Throttle valve opening should be at least 60 percent.
7. If throttle valve opening is at least 60 percent, go to step 10. If throttle valve opening is not at least 60 percent, problem may exist in accelerator pedal position sensor, wiring circuit or ECM. Go to step 15 for testing of accelerator pedal position sensor.
8. Access ECM. On Land Cruiser, ECM is located above glove box, near passenger's side of instrument panel. On Tundra, ECM is located behind glove box and air inlet duct. On all models, for illustration of ECM location, see THEORY & OPERATION article. On all models, ensure ignition is turned on. Using voltmeter, check voltage between ECM terminals VPA and E2 with accelerator pedal released and with accelerator pedal fully depressed. (Scheme 178) See «ECM TERMINAL WIRE COLOR IDENTIFICATION»(ref-3026-S31551482702000041700000) table. ECM TERMINAL WIRE COLOR IDENTIFICATION Application & ECM Terminal Wire Color Land Cruiser E2 Brown/White VPA Red Tundra E2 Green/White VPA Green/Red
9. Voltage should.3-.9 volt with accelerator pedal released and 3.2-4.8 volts with accelerator pedal fully depressed. If voltage is within specification, go to next step. If voltage is not within specification, problem may exist in accelerator pedal position sensor, wiring circuit or ECM. Go to step 15 for testing of accelerator pedal position sensor.
10. Start engine and allow engine to idle. Check operation of Malfunction Indicator Light (MIL) on instrument panel. If MIL is not illuminated, go to next step. If MIL is illuminated, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.
11. To test operation of air assist system, allow engine to warm to normal operating temperature. Apply parking brake. Place transmission in Neutral. Ensure A/C is off. Note engine idle speed. Engine idle speed should be 650-750 RPM. If all previous steps have been performed, drive vehicle to verify proper operation of throttle body.
12. To test throttle control motor, disconnect electrical connector at throttle control motor. (Scheme 177) Note terminal identification on throttle control motor. (Scheme 179)
13. Using ohmmeter, check resistance between specified terminals on throttle control motor. See «THROTTLE CONTROL MOTOR RESISTANCE»(ref-3026-S21897667402000041700000) table. If resistance is within specification, reinstall electrical connector. Go to next step. If resistance is not within specification, replace throttle control motor. See THROTTLE BODY under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. THROTTLE CONTROL MOTOR RESISTANCE Terminal No. Ohms @ 68°F (20°C) 1 (M+) & 2 (M-).3-100.0 3 (CL-) & 4 (CL+) 4.2-5.2
14. To test TP sensor, disconnect electrical connector at TP sensor. (Scheme 177) Using ohmmeter, check resistance between terminals VC and E2 on TP sensor. (Scheme 180) Replace TP sensor if resistance is not 1250-2350 ohms at 68°F (20°C). See THROTTLE BODY under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
15. To test accelerator pedal position sensor, disconnect electrical connector at accelerator pedal position sensor. (Scheme 177) Using ohmmeter, check resistance between terminals VC and E2 on accelerator pedal position sensor. (Scheme 181) Replace accelerator pedal position sensor if resistance is not 1640-3280 ohms at 68°F (20°C). See THROTTLE BODY under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.

IGNITION SYSTEMS

Note. For basic ignition checks, see IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article.

Knock Sensors

See KNOCK SENSORS under ENGINE SENSORS & SWITCHES.

Scheme 180

Scheme 181

Scheme 182

Scheme 183

Scheme 184

Scheme 185

Scheme 186

Manufacturer does not list an EGR system test, only individual component testing is listed. If a problem exists in EGR system, a Diagnostic Trouble Code (DTC) P0401, P0402, P1410 or P1411 may be stored in Engine Control Module (ECM). See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

See EGR GAS TEMPERATURE SENSOR under ENGINE SENSORS & SWITCHES.

EGR POSITION SENSOR

Note. EGR position sensor may also be referred to as EGR valve position sensor.

1. Disconnect electrical connector at EGR position sensor. EGR position sensor is located on top of EGR valve. (Scheme 189)
2. Using ohmmeter, check resistance between terminals E2 and VC on EGR position sensor. (Scheme 189) Resistance should be 1500-4300 ohms. If resistance is within specification, reinstall electrical connector on EGR position sensor and go to next step. If resistance is not within specification, replace EGR position sensor.
3. To test EGR position sensor output voltage, disconnect vacuum hose from EGR valve. Remove glove box for access to Engine Control Module (ECM).
4. Turn ignition on. Using voltmeter, check voltage between ECM terminals E2 and VC. (Scheme 190) See «ECM TERMINAL APPLICATION»(ref-3026-S25421040492000041700000) table for E2 and VC terminal wire colors. Voltage should be 4.5-5.5 volts. Remove voltmeter.
5. Connect voltmeter between ECM terminals E2 and EGLS. (Scheme 191) See «ECM TERMINAL APPLICATION»(ref-3026-S25421040492000041700000) table for E2 and EGLS terminal wire colors.
6. Using vacuum pump, apply 5.1 in. Hg of vacuum to EGR valve and note voltage. Voltage should be 3.2-5.1 volts with vacuum applied on EGR valve. Release vacuum from EGR valve and note voltage. Voltage should be.4-1.6 volts with vacuum released from EGR valve. Replace EGR position sensor if voltage is not within specification. Remove vacuum pump and reinstall vacuum hose on EGR valve.

ECM TERMINAL APPLICATION

Scheme 187

Scheme 188

Scheme 189

EGR VACUUM CONTROL VALVE

Note. EGR vacuum control valve may also be referred to as EGR VCV.

1. Disconnect vacuum hoses and remove EGR vacuum control valve. EGR vacuum control valve is located on top of engine, near EGR valve. (Scheme 183)
2. Plug port "Z" and connect vacuum pump to port "S" on EGR vacuum control valve. see scheme 128
3. Using vacuum pump, apply 11.8 in. Hg of vacuum to EGR vacuum control valve. Vacuum pump should be operated 3 times so applied vacuum on EGR vacuum control valve remains at 8.6-11.8 in. Hg of vacuum.
4. Stop operating the vacuum pump after 3 times and note vacuum reading. Vacuum reading should decrease to 4.4-7.1 in. Hg of vacuum after 10 seconds. Replace EGR vacuum control valve if vacuum reading is not within specification.

Scheme 190

Scheme 191

1. Remove "V" bank cover and emission control valve set located on top of engine for access to EGR VSV. (Scheme 83)
2. Remove EGR VSV. Using ohmmeter, ensure continuity exists between electrical terminals on EGR VSV and resistance is 27-33 ohms at 68°F (20°C). Replace EGR 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 EGR VSV. 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 flows from port "G". Perform STEP 1 in illustration. see scheme 129
5. Apply battery voltage and ground to electrical terminals on EGR VSV. Apply air pressure to port "E". Ensure air flows from port "F" and not from port "G". Perform STEP 2 in illustration. see scheme 129 Replace EGR VSV if defective. Reinstall EGR VSV.

1. Remove EGR valve. See EGR VALVE under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
2. Inspect EGR valve for restricted passages caused by carbon deposits. Using vacuum pump, apply vacuum directly to EGR valve and ensure valve opens. Release vacuum and ensure valve closes. Replace EGR valve if defective.

FUEL EVAPORATION SYSTEM

Note. Fuel Evaporative (EVAP) system may contain different components depending on application. (Scheme 182)- (Scheme 188). When testing fuel EVAP system components, it may be necessary to use proper illustration to determine component location.

Note. On Avalon, Camry and Camry Solara, 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 182)- (Scheme 183). Overfill check valve may also be referred to as On-Board Refueling Vapor Recovery Overfill Check Valve (ORVR-OCKV) or fill check valve. Cut-off valve may also be referred to On-Board Refueling Vapor Recovery Cut-Off Valve (ORVR-COV). For testing of fuel EVAP system and ORVR system, see appropriate FUEL EVAP SYSTEM TEST.

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

Charcoal Canister

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

EVAP Vacuum Switching Valve

1. Remove EVAP Vacuum Switching Valve (VSV). (Scheme 182)- (Scheme 188). See «EVAP VSV LOCATIONS»(ref-3026-S36872501552000041700000) table. EVAP VSV LOCATIONS Application Location Avalon Front VSV On Emission Control Valve Set On Top Of Engine, Near Intake Manifold & Contains Blue 2-Pin Electrical Connector With Black/Red & Black/White Wires Camry, Camry Solara & Sienna Front VSV On Emission Control Valve Set On Top Of Engine, Near Intake Manifold & Contains Blue 2-Pin Electrical Connector With Light Green & Black/Yellow Wires Land Cruiser On Driver's Side Center Of Intake Manifold Below Intake Manifold Cover On Top Of Engine & Contains Black 2-Pin Electrical Connector With Blue/Black & Black/Yellow Wires Tacoma On End Of Charcoal Canister & Contains Black 2-Pin Electrical Connector With White/Red & White/Green Wires Tundra 3.4L V6 At Driver's Side Rear Corner Of Air Intake Chamber & Contains Black 2-Pin Electrical Connector With White/Blue & White/Green Wires 4.7L V8 At Driver's Side Center Of Intake Manifold & Contains Black 2-Pin Electrical Connector With Red & White/Green Wires 4Runner On End Of Charcoal Canister & Contains Black 2-Pin Electrical Connector With White/Blue & White/Green Wires
2. Using ohmmeter, ensure continuity exists between electrical terminals on EVAP VSV and resistance is within specification. See «EVAP VSV RESISTANCE»(ref-3026-S29435489542000041700000) table. Replace EVAP VSV if no continuity exists or resistance is not within specification. EVAP VSV RESISTANCE Application Ohms @ 68°F (20°C) Avalon, Camry, Camry Solara & Sienna 27-33 Land Cruiser & Tacoma 30-34 Tundra 3.4L V6 29-33 4.7L V8 30-34 4Runner 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 no air flows from port "F". Perform STEP 1 in illustration. (Scheme 194)and (Scheme 195).
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 194)and (Scheme 195). Replace EVAP VSV if defective.

Scheme 192

Scheme 193

Overfill Check Valve (Avalon, Camry & Camry Solar)

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 (Avalon, Camry & Camry Solara)

1. Remove pressure switching valve Vacuum Switching Valve (VSV). See «PRESSURE SWITCHING VALVE VSV LOCATION»(ref-3026-S09557462952000032900000) table. (Scheme 182)and (Scheme 183). PRESSURE SWITCHING VALVE VSV LOCATION Application Location Avalon On Bracket At Charcoal Canister Near Fuel Tank & Contains 2-Pin Electrical Connector With Pink/Black & Black/White Wires Camry On Bracket At Charcoal Canister Near Fuel Tank & Contains 2-Pin Electrical Connector With Violet & Black/Yellow Wires Camry Solara On Bracket At Charcoal Canister Near Fuel Tank & Contains 2-Pin Electrical Connector With White/Red & Red Wires
2. Using ohmmeter, ensure continuity exists between electrical terminals on pressure switching valve VSV and resistance is 37-44 ohms @ 68°F (20°C). Replace pressure 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 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 196)
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 196) Replace pressure switching valve VSV if defective.

Scheme 194

Scheme 195

Scheme 196

Scheme 197

Scheme 198

Scheme 199

Scheme 200

Scheme 201

Scheme 202

Scheme 203

Scheme 204

1. Ensure ignition is off. To test vapor pressure sensor supply voltage, disconnect electrical connector at vapor pressure sensor. (Scheme 182)- (Scheme 188). See «VAPOR PRESSURE SENSOR LOCATION»(ref-3026-S41375574502000041700000) table. VAPOR PRESSURE SENSOR LOCATION Application Location Avalon On Charcoal Canister, Near Fuel Tank & Contains Black 3-Pin Electrical Connector With White, Pink & Blue/Red Wires Camry On Charcoal Canister, Near Fuel Tank & Contains Black 3-Pin Electrical Connector With Brown, Pink & Yellow Wires Camry Solara On Charcoal Canister, Near Fuel Tank & Contains Black 3-Pin Electrical Connector With Brown, Blue/Red & Yellow Wires Land Cruiser On Rear Corner Of Charcoal Canister & Contains Black 3-Pin Electrical Connector With Brown/White, Blue/Red & Blue/Black Wires Sienna On Firewall, Near Brake Master Cylinder & Contains Black 3-Pin Electrical Connector With Brown, Blue/Red & Yellow Wires Tacoma On Firewall, Above Brake Booster & Contains Black 3-Pin Electrical Connector With Brown/Black, Green/Black & Red/Yellow Wires Tundra On Rear Corner Of Charcoal Canister & Contains Black 3-Pin Electrical Connector With Green/White, Red/Green & Green/Black Wires 4Runner On Firewall, Above Brake Booster & Contains Black 3-Pin Electrical Connector With Blue/Black, Green/Black & Yellow Wires
2. Turn ignition on. Using voltmeter, measure voltage between terminals VC and E2 on wiring harness side of electrical connector for vapor pressure sensor. (Scheme 197) The VC and E2 terminals are the 2 outer terminals. DO NOT use center terminal. Supply voltage should be 4.5-5.5 volts.
3. If supply voltage is not within specification, check wiring circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. If supply voltage is within specification, turn ignition off. Reinstall electrical connector on vapor pressure sensor.
4. To test vapor pressure sensor output voltage, turn ignition on. Disconnect vacuum hose from vapor pressure sensor. (Scheme 198)- (Scheme 202).
5. Obtain access to Engine Control Module (ECM). See «ECM LOCATION»(ref-3026-S36537420232000041700000) table. Connect voltmeter between specified ECM terminals. (Scheme 203)- (Scheme 206). See «ECM TERMINAL APPLICATION»(ref-3026-S20563341902000041700000) table. ECM LOCATION Model (1) Location Avalon, Camry & Camry Solara Behind Glove Box Land Cruiser Above Glove Box, Near Passenger's Side Of Instrument Panel Sienna Behind Glove Box, Just Above Passenger's Side Lower Instrument Panel Cover Tacoma & 4Runner Behind Glove Box Tundra Behind Glove Box & Air Inlet Duct (1) For illustration of ECM location, see THEORY & OPERATION article. ECM TERMINAL APPLICATION Application & Terminal Wire Color Avalon E2 White PTNK Pink Camry E2 Brown PTNK Pink Camry Solara E2 Brown PTNK Blue/Red Land Cruiser E2 Brown/White PTNK Blue/Black Sienna E2 Brown PTNK Blue/Red Tacoma Calif. Emission Vehicles E2 Brown/Black PTNK Red/Green Except Calif. Emission Vehicles E2 Brown/Black PTNK Red/Yellow Tundra E2 Green/White PTNK Red/Green 4Runner E2 Blue/Black PTNK Yellow
6. Using vacuum pump, apply.59 in. Hg of vacuum to vapor pressure sensor. Ensure output voltage is within specification. See «VAPOR SENSOR OUTPUT VOLTAGE»(ref-3026-S26680314712000041700000) table.
7. Release vacuum from vapor pressure sensor. Ensure output voltage is within specification. See «VAPOR SENSOR OUTPUT VOLTAGE»(ref-3026-S26680314712000041700000) table.
8. Apply.22 psi (.015 kg/cm 2 ) to vapor pressure sensor. Ensure output voltage is within specification. See «VAPOR SENSOR OUTPUT VOLTAGE»(ref-3026-S26680314712000041700000) table. Replace vapor sensor if output voltage is not within specification. Reconnect vacuum hose. VAPOR SENSOR OUTPUT VOLTAGE Condition Output Voltage Vacuum Applied 1.3-2.1 Vacuum Released 3.0-3.6 Pressure Applied 4.2-4.8

Vapor Pressure Sensor Vacuum Switching Valve (Land Cruiser, Sienna, Tacoma, Tundra & 4Runner)

1. Remove vapor pressure sensor Vacuum Switching Valve (VSV). Vapor pressure sensor VSV is located on charcoal canister. (Scheme 184)- (Scheme 188).
2. Using ohmmeter, ensure continuity exists between electrical terminals on vapor pressure sensor VSV and resistance is 37-44 ohms @ 68°F (20°C). Replace vapor pressure sensor 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 vapor pressure sensor VSV. Replace vapor pressure sensor VSV if continuity exists between electrical terminal and body of vapor pressure sensor VSV.
4. To test vapor pressure sensor VSV operation, apply air pressure to port "E". Ensure air flows from port "G" and not from port "F". Perform STEP 1 in illustration. (Scheme 207)and (Scheme 208).
5. Apply battery voltage and ground to electrical terminals on vapor pressure sensor VSV. Apply air pressure to port "E". Ensure air flows from port "F" and not from port "G". Perform STEP 2 in illustration. (Scheme 207)and (Scheme 208). Replace vapor pressure sensor VSV if defective.

Scheme 205

Scheme 206

Avalon, Camry, Camry Solara, Land Cruiser, Sienna, Tacoma & Tundra 4.7L V8

1. Remove PCV valve. See «PCV VALVE LOCATION»(ref-3026-S29590399702000041700000) table.
2. Apply air pressure to PCV valve at cylinder head side of PCV valve. Ensure air flows easily through PCV valve. Apply air pressure to PCV valve at intake manifold side of PCV valve. Ensure air flows through PCV valve with some resistance. Replace PCV valve if valve does not function as described.

Tundra 3.4L V6 & 4Runner

1. Remove PCV valve. See «PCV VALVE LOCATION»(ref-3026-S29590399702000041700000) table.
2. Apply air pressure to PCV valve at cylinder head side of PCV valve. Ensure air flows easily through PCV valve. Apply air pressure to PCV valve at intake manifold side of PCV valve. Ensure air flows through PCV valve with some resistance.
3. Apply air pressure to PCV valve at intake manifold side of PCV valve while using small screwdriver to push upward on valve located inside PCV valve, at cylinder head side of PCV valve. Ensure air flows through PCV valve with strong resistance. Replace PCV valve if valve does not function as described. PCV VALVE LOCATION Application Location Avalon, Camry, Camry Solara & Sienna On Firewall Side Valve Cover At Timing Belt End Of Engine Land Cruiser At Front Of Driver's Side Valve Cover, Below Oil Fill Cap Tacoma & 4Runner Front Of Passenger's Side Valve Cover Tundra 3.4L V6 Front Of Passenger's Side Valve Cover 4.7L V8 At Front Of Driver's Side Valve Cover, Below Oil Fill Cap

VARIABLE VALVE TIMING (VVT) SYSTEM

Note. VVT system is used only on Avalon models. If problem exists in VVT system, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

VVT sensor may also be referred to as camshaft position sensor. For testing camshaft position sensor, see CAMSHAFT POSITION SENSOR RESISTANCE under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article.

VARIABLE VALVE TIMING (VVT) CAMSHAFT TIMING OIL CONTROL VALVE

Note. 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.

Scheme 207

Scheme 208

1. Remove "V" bank cover on top of engine for access to VVT camshaft timing oil control valves. VVT camshaft timing oil control valves are located on end of cylinder head at flywheel end of engine. (Scheme 209)
2. To check VVT camshaft timing oil control valve resistance, disconnect electrical connector at appropriate VVT camshaft timing oil control valve. Using ohmmeter, check resistance between electrical terminals on VVT camshaft timing oil control valve. Resistance should be 6.9-7.9 ohms @ 68°F (20°C). If resistance is within specification, go to next step. If resistance is not within specification, replace VVT camshaft timing oil control valve.
3. To check VVT camshaft timing oil control valve operation, remove retaining bolt and appropriate VVT camshaft timing oil control valve with "O" ring from cylinder head. Note movement of the 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 210) 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 210) Replace VVT camshaft timing oil control valve if operation is not as specified. Reinstall VVT camshaft timing oil control valve using NEW "O" ring. Tighten retaining bolt to 66 INCH lbs. (7.5 N.m).

Tacoma With M/T & 4Runner With M/T

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS - V6 & V8 article. Shut engine off. Remove cap, filter and separator from dashpot on throttle body. (Scheme 211)
2. Start engine. Maintain engine speed at 2500 RPM. Plug Vacuum Transmitting Valve (VTV) hole in dashpot with your finger. (Scheme 212)
3. Release throttle. Dashpot should be extended and dashpot setting RPM should be 1800-2200 RPM. If dashpot setting RPM is not within specification, rotate dashpot adjusting screw to obtain correct RPM. (Scheme 213)
4. Remove finger from VTV hole in dashpot. Ensure engine returns to proper idle speed in approximately one second. Install separator, filter and cap. Ensure filter is installed with the coarse surface facing outward (away from dashpot).

Scheme 209

Scheme 210

Scheme 211

1. Start engine and warm engine to normal operating temperature. Ensure idle speed is within specification. See IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS - V6 & V8 article.
2. Shut engine off. Disconnect and plug vacuum hose at throttle opener near throttle body. (Scheme 214)- see scheme 166. Start engine and note engine speed. Engine speed should be within specification. See «THROTTLE OPENER SPECIFICATIONS»(ref-3026-S20853487872000060200000) table.
3. If engine speed is not within specification, replace throttle body. Shut engine off. Reinstall vacuum hose on throttle opener. Start engine and ensure engine returns to proper idle speed. THROTTLE OPENER SPECIFICATIONS (1) Application RPM Avalon 1100-1700 Camry, Camry Solara, Sienna, Tacoma, Tundra & 4Runner 900-1950 (1) Check with throttle opener vacuum hose disconnected and plugged, engine at normal operating temperature and electric cooling fan turned off (if equipped).

Scheme 212

Scheme 213

Scheme 214

Scheme 215