Engine Control System Tests W/codes: Diagnosis Toyota Avalon XX10 рестайлинг

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS

Diagnosis & Repair (Models With Calif. Emissions & Except Calif. Emissions With Engine Immobilizer System &/Or Traction Control)

1. Connect scan tool to DLC No. 3 connector. (Scheme 38) Start vehicle engine and allow to idle. Using scan tool, monitor MAF flow rate. If scan tool reading is 0.0 gm/sec., go to next step. If reading is 271 gm/sec. or more once engine is at normal operating temperature, go to step 5).
2. Turn ignition off. Disconnect MAF sensor connector. Turn ignition on. Using DVOM, measure voltage between ground and terminal No. 4 (Light Green wire) at MAF sensor wiring harness connector. (Scheme 39) If voltage is 9-14 volts, go to next step. If voltage is not 9- 14 volts, check for open circuit in wiring harness between EFI main relay and MAF sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
3. Access ECM behind glove box. Ensure shift lever is in Neutral or Park position. Ensure A/C switch is off. Start engine and allow it to idle. Backprobing ECM connector, measure voltage between ground and terminal No. 10 (Pink wire) at ECM E7 connector. (Scheme 40) If voltage is 1.1-1.5 volts, replace ECM.
4. If voltage is not 1.1-1.5 volts, check for open or short circuit in wiring harness between MAF sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace MAF sensor.
5. Turn ignition off. Access ECM behind glove box. Using ohmmeter, backprobe ECM connector. Check continuity between ground and terminal No. 9 (Red/Black wire) at ECM E7 connector. If continuity does not exist, replace ECM. If continuity exists, check for open circuit in wiring harness between MAF sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace MAF sensor.

Scheme 38

Scheme 39

Scheme 40

Diagnosis & Repair (Except Calif. Emission Models Without Engine Immobilizer System &/Or Traction Control)

1. Connect scan tool to DLC No. 3 connector. (Scheme 38) Start vehicle engine and allow to idle. Using scan tool, monitor MAF flow rate. If scan tool reading is 0.0 gm/sec., go to next step. If reading is 271 gm/sec. or more once engine is at normal operating temperature, go to step 5).
2. Turn ignition off. Disconnect MAF sensor connector. Turn ignition on. Using DVOM, measure voltage between ground and terminal No. 4 (Light Green wire) at MAF sensor wiring harness connector. (Scheme 39) If voltage is 9-14 volts, go to next step. If voltage is not 9- 14 volts, check for open circuit in wiring harness between EFI main relay and MAF sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
3. Access ECM behind glove box. Start engine. Backprobing ECM connector, measure voltage between ground and terminal No. 8 (Pink wire) at ECM E7 connector. (Scheme 41) If voltage is 1.1-1.5 volts, replace ECM.
4. If voltage is not 1.1-1.5 volts, check for open or short circuit in wiring harness between MAF sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace MAF sensor.
5. Turn ignition off. Access ECM behind glove box. Using ohmmeter, backprobe ECM connector. Check continuity between ground and terminal No. 7 (Red/Black wire) at ECM E6 connector. If continuity does not exist, replace ECM. If continuity exists, check for open circuit in wiring harness between MAF sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace MAF sensor.

Scheme 41

Diagnosis & Repair Procedure

If only DTC P0101 is displayed, replace MAF sensor. If other codes are displayed, diagnose and repair those codes first and retest.

1. Connect scan tool to DLC No. 3 connector. (Scheme 38) Turn ignition on. Using scan tool, monitor IAT sensor temperature. If temperature displayed is same as outside temperature, check component and ECM connections. Problem is intermittent.
2. If temperature displayed is 284°F (140°C) or more, go to step 5). If temperature displayed is -40°F (-40°C), turn ignition off. Disconnect MAF sensor connector. Using jumper wire, connect MAF sensor wiring harness connector terminals No. 1 and 2. (Scheme 39) Turn ignition on. Using scan tool, monitor IAT sensor temperature.
3. If temperature displayed is 284°F (140°C) or more, replace MAF sensor. If temperature displayed is less than 284°F (140°C), turn ignition off. Remove jumper wire. Access ECM behind glove box. Connect jumper wire between terminals No. 18 (Brown wire) and No. 22 (Blue/Yellow wire) at ECM E7 connector. (Scheme 40)
4. If temperature displayed on scan tool is 284°F (140°C) or more, check and repair wiring harness between MAF sensor wiring harness connector and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed on scan tool is less than 284°F (140°C), replace ECM.
5. Turn ignition off. Disconnect MAF sensor connector. Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace MAF sensor. If temperature displayed is not -40°F (-40°C), turn ignition off.
6. Access ECM behind glove box. Disconnect ECM E7 connector. (Scheme 40) Turn ignition on. If temperature displayed is -40°F (-40°C), repair short circuit in wiring harness between MAF sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed by scan tool is not -40°F (-40°C), replace ECM.

1. Connect scan tool to DLC No. 3 connector. (Scheme 38) Turn ignition on. Using scan tool, monitor IAT sensor temperature. If temperature displayed is same as outside temperature, check component and ECM connections. Problem is intermittent.
2. If temperature displayed is 284°F (140°C) or more, go to step 5). If temperature displayed is -40°F (-40°C), turn ignition off. Disconnect MAF sensor connector. Using a jumper wire, connect MAF sensor wiring harness connector terminals No. 1 and 2. (Scheme 39) Turn ignition on. Using scan tool, monitor IAT sensor temperature.
3. If temperature displayed is 284°F (140°C) or more, replace MAF sensor. If temperature displayed is less than 284°F (140°C), turn ignition off. Remove jumper wire. Access ECM behind glove box. Connect jumper wire between terminals No. 22 (Brown wire) and No. 21 (Blue/Red wire) at ECM E7 connector. (Scheme 41)
4. If temperature displayed on scan tool is 284°F (140°C) or more, check and repair wiring harness between MAF sensor wiring harness connector and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed on scan tool is less than 284°F (140°C), replace ECM.
5. Turn ignition off. Disconnect MAF sensor connector. Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace MAF sensor. If temperature displayed is not -40°F (-40°C), turn ignition off.
6. Access ECM behind glove box. Disconnect ECM E7 connector. (Scheme 41) Turn ignition on. If temperature displayed is -40°F (-40°C), repair short circuit in wiring harness between MAF sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed by scan tool is not -40°F (-40°C), replace ECM.

1. Connect scan tool to DLC No. 3 connector. (Scheme 38) Turn ignition on. Using scan tool, monitor ECT sensor temperature. If temperature displayed is same as actual coolant temperature, check component and ECM connections. Problem is intermittent.
2. If temperature displayed is 284°F (140°C) or more, go to step 5). If temperature displayed is -40°F (-40°C), turn ignition off. Disconnect ECT sensor connector (2-pin connector with Green/Black wire and Brown wire). ECT sensor is located in coolant housing in front of intake manifold on timing belt side of engine. Using jumper wire, connect ECT sensor wiring harness connector terminals. Turn ignition on. Using scan tool, monitor ECT sensor temperature.
3. If temperature displayed is 284°F (140°C) or more, replace ECT sensor. If temperature displayed is less than 284°F (140°C), turn ignition off. Remove jumper wire. Access ECM behind glove box. Connect jumper wire between terminals No. 18 (Brown wire) and No. 14 (Green/Black wire) at ECM E7 connector. (Scheme 40)
4. If temperature displayed on scan tool is 284°F (140°C) or more, repair open circuit in wiring harness between ECT sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed on scan tool is less than 284°F (140°C), replace ECM.
5. Turn ignition off. Disconnect ECT sensor connector. Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace ECT sensor. If temperature displayed is not -40°F (-40°C), turn ignition off.
6. Access ECM behind glove box. Disconnect ECM E7 connector. (Scheme 40) Turn ignition on. If temperature displayed is -40°F (-40°C), repair short circuit in wiring harness between ECT sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed by scan tool is not -40°F (-40°C), replace ECM.

1. Connect scan tool to DLC No. 3 connector. (Scheme 38) Turn ignition on. Using scan tool, monitor ECT sensor temperature. If temperature displayed is same as actual coolant temperature, check component and ECM connections. Problem is intermittent.
2. If temperature displayed is 284°F (140°C) or more, go to step 5). If temperature displayed is -40°F (-40°C), turn ignition off. Disconnect ECT sensor connector (2-pin connector with Green/Black wire and Brown wire). ECT sensor is located in coolant housing in front of intake manifold on timing belt side of engine. Using jumper wire, connect ECT sensor wiring harness connector terminals. Turn ignition on. Using scan tool, monitor ECT sensor temperature.
3. If temperature displayed is 284°F (140°C) or more, replace ECT sensor. If temperature displayed is less than 284°F (140°C), turn ignition off. Remove jumper wire. Access ECM behind glove box. Connect jumper wire between terminals No. 22 (Brown wire) and No. 20 (Green/Black wire) at ECM E7 connector. (Scheme 41)
4. If temperature displayed on scan tool is 284°F (140°C) or more, repair open circuit in wiring harness between ECT sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed on scan tool is less than 284°F (140°C), replace ECM.
5. Turn ignition off. Disconnect ECT sensor connector. Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace ECT sensor. If temperature displayed is not -40°F (-40°C), turn ignition off.
6. Access ECM behind glove box. Disconnect ECM E7 connector. (Scheme 41) Turn ignition on. If temperature displayed is -40°F (-40°C), repair short circuit in wiring harness between ECT sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed by scan tool is not -40°F (-40°C), replace ECM.

Diagnosis & Repair

If any other codes are displayed, diagnose and repair those codes first and retest. If only DTC P0116 is displayed, remove and inspect cooling system thermostat. Replace thermostat as necessary and retest. If thermostat is okay, replace ECT sensor.

1. Connect scan tool to DLC No. 3 connector. (Scheme 38) Turn ignition on. Using scan tool, monitor throttle valve opening percentage. Opening percentage should be approximately 10 percent with fully closed throttle.
2. Depress accelerator pedal to floor (WOT). Opening percentage should be approximately 75 percent. If percentages are as specified, check all connections. Problem may be intermittent.
3. If percentages are not as specified, turn ignition off. Disconnect TP sensor connector. Ensure ignition is on. Using DVOM, measure voltage between ground and terminal No. 1 (Blue/Red wire) at TP sensor wiring harness connector. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, go to step 7).
4. Check TP sensor. See ENGINE SENSORS & SWITCHES in appropriate SYSTEM/COMPONENT TESTS article. Replace sensor as necessary. If sensor is okay, go to next step.
5. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 23 (Black/Yellow wire) and No. 18 (Brown wire) at ECM E7 connector. (Scheme 40) Voltage should be.3-1.0 volt with throttle fully closed and 2. 7-5.2 volts with throttle fully open (WOT).
6. If voltage is as specified, replace ECM. If voltage is not as specified, check for an open or short in Black/Yellow wire. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
7. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (Brown wire) at ECM E7 connector. (Scheme 40) If voltage is 4.5-5.5 volts, check wiring harness for an open in Blue/Red wire. If voltage is not 4.5-5.5 volts, replace ECM.

1. Connect scan tool to DLC No. 3 connector. (Scheme 38) Turn ignition on. Using scan tool, monitor throttle valve opening percentage. Opening percentage should be approximately 10 percent with fully closed throttle.
2. Depress accelerator pedal to floor (WOT). Opening percentage should be approximately 75 percent. If percentages are as specified, check all connections. Problem may be intermittent.
3. If percentages are not as specified, turn ignition off. Disconnect TP sensor connector. Ensure ignition is on. Using DVOM, measure voltage between ground and terminal No. 1 (Blue/Red wire) at TP sensor wiring harness connector. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, go to step 7).
4. Check TP sensor. See ENGINE SENSORS & SWITCHES in appropriate SYSTEM/COMPONENT TESTS article. Replace sensor as necessary. If sensor is okay, go to next step.
5. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 7 (Black/Yellow wire) and No. 22 (Brown wire) at ECM E7 connector. (Scheme 41) Voltage should be.3-1.0 volt with throttle fully closed and 2. 7-5.2 volts with throttle fully open (WOT).
6. If voltage is as specified, replace ECM. If voltage is not as specified, check for an open or short in Black/Blue wire. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
7. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 1 (Blue/Red wire) and No. 22 (Brown wire) at ECM E7 connector. (Scheme 41) If voltage is 4.5-5.5 volts, check wiring harness for an open in Blue/Red wire. If voltage is not 4.5-5.5 volts, replace ECM.

If only DTC P0121 is displayed, replace TP sensor. If other codes are displayed, diagnose and repair those codes first and retest.

1. Connect scan tool to DLC No. 3 connector. (Scheme 38) Start vehicle and warm engine to normal operating temperature. Using scan tool, monitor each oxygen sensor in front of converter. Snap accelerate engine to about 4000 RPM 3 times. Both sensors should indicate a rich signal (.45 volt or more) at least once.
2. If a rich signal is indicated for both sensors at least once, replace ECM. If either sensor does not display a rich signal at least once, perform misfire diagnosis. See «DTCS P0301-P0306»(ref-22530-S36677205092001010300000): CYLINDERS NO. 1-6 MISFIRE DETECTED test. Repair as necessary. If no misfire is detected, go to next step.
3. Check wiring harness between ECM and suspect sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace oxygen sensor.

Test Drive Confirmation

1. If using OBD-II scan tool, go to next step. If using Toyota scan tool, connect scan tool. (Scheme 38) Switch scan tool to CHECK mode. Start and warm engine to normal operating temperature. Drive vehicle at 38-65 MPH with engine speed at 1600-3200 RPM for 3-5 minutes. If malfunction exists, MIL will illuminate.
2. If using OBD-II scan tool, start and warm engine to normal operating temperature. Drive vehicle at 38-65 MPH with engine speed at 1600-3200 RPM for 3-5 minutes. Stop vehicle and turn ignition off. Repeat driving part of test. If malfunction exists, MIL will illuminate.

Note. Bank No. 1 refers to bank that includes cylinder No. 1. Bank No. 2 refers to bank without cylinder No. 1. AFS No. 1 refers to sensor in exhaust manifold.

1. If only DTC P0125 is displayed, go to next step. If other codes are displayed, diagnose and repair those codes first and retest system.
2. Check for open or short circuit in wiring harness between ECM and suspect AFS. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, go to next step.
3. Disconnect suspect AFS connector. One AFS is located in each exhaust manifold. Using ohmmeter, measure resistance between Blue wire and Blue/Red wire (bank No. 1) or between Blue wire and Black/Red wire (bank No. 2) at AFS connector. Resistance should be .8-1.4 ohms at 68°F (20°C). Replace AFS as necessary. If resistance is .8-1.4 ohms, go to next step.
4. Reconnect AFS connector. Start engine and raise engine speed to 2500 RPM for 90 seconds. Using scan tool, monitor each AFS output voltage. See «AIR/FUEL RATIO SENSOR SPECIFICATIONS»(ref-22530-S07302566212001010300000) table. If voltage is as specified, go to next step. If voltage is not as specified, replace AFS. AIR/FUEL RATIO SENSOR SPECIFICATIONS Application (1) Voltage Using OBD-II Scan Tool Engine Idling 0.66 Engine Racing 0.76 Or More Driving Vehicle (2) 0.56 Or Less Using Toyota Scan Tool Engine Idling 3.3 Engine Racing 3.8 Or More Driving Vehicle (2) 2.8 Or Less (1) Voltage should not remain at specification given. (2) Drive vehicle at 25 MPH or more with engine speed at 1500 RPM or more while opening and closing throttle valve.
5. Perform TEST DRIVE CONFIRMATION. If DTC P0125 resets, replace ECM. If DTC P0125 does not reset, no problem is indicated at this time.

1. If using OBD-II scan tool, go to next step. If using Toyota scan tool, connect scan tool. (Scheme 38) Switch scan tool to CHECK mode. Start and warm engine to normal operating temperature. Drive vehicle at 31-40 MPH for 1-3 minutes. Stop vehicle and allow to idle for one minute. If malfunction exists, MIL will illuminate.
2. If using OBD-II scan tool, start and warm engine to normal operating temperature. Drive vehicle at 31-40 MPH for 1-3 minutes. Stop vehicle and allow to idle for one minute. Turn ignition off. Repeat driving and idle part of test. If malfunction exists, MIL will illuminate.

1. Check for open or short circuits in wiring harness between ECM and oxygen sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, connect scan tool. (Scheme 38)
2. Start engine and warm to normal operating temperature. Monitor heated oxygen sensor output voltage and short-term fuel trim. If scan tool indicates a lean condition (.6 volt or less, +20 trim) or rich condition (.4 volt or more, -20 trim), see appropriate DTC P0171 OR P0172: SYSTEM TOO LEAN/RICH test.
3. If scan tool indicates other than reading in step 2), operate engine at 2500 RPM for 90 seconds. Allow engine to idle and monitor oxygen sensor voltage. If voltage constantly fluctuates from less than.4 volt to more than.6 volt, perform TEST DRIVE CONFIRMATION. If voltage does not fluctuate as specified, replace sensor.

If only DTC P0133 or P0153 is displayed, replace oxygen sensor. DTC P0133 is for bank No. 1, sensor No. 1. DTC P0153 is for bank No. 2, sensor No. 1. If other codes are displayed, diagnose and repair those codes first and retest system.

Diagnosis & Repair (With Engine Immobilizer System &/Or Traction Control)

1. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM connector. If DTC P0135 is set, measure voltage between ground and terminal No. 3 (Blue/Black wire) at ECM E7 connector. If DTC P0155 is set, measure voltage between ground and terminal No. 4 (Blue/Red wire) at ECM E7 connector. (Scheme 40) Voltage for each circuit should be 9-14 volts.
2. If voltage is as specified, replace ECM. If voltage is not as specified, turn ignition off. Disconnect appropriate oxygen sensor connector. Using ohmmeter, measure resistance between terminals No. 1 and 2 at oxygen sensor connector. See «IDENTIFYING OXYGEN SENSOR HEATER TERMINALS»(ref-22530-S15556885492001010300000) table.
3. If resistance is 11-16 ohms at 68°F (20°C), check wiring harness between ECM and sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If resistance is not 11-16 ohms at 68°F (20°C), replace sensor.

IDENTIFYING OXYGEN SENSOR HEATER TERMINALS

Diagnosis & Repair (Without Engine Immobilizer System &/Or Traction Control)

1. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM connector. If DTC P0135 is set, measure voltage between ground and terminal No. 11 (Blue/Black wire) at ECM E6 connector. If DTC P0155 is set, measure voltage between ground and terminal No. 10 (Blue/Red wire) at ECM E6 connector. (Scheme 41) Voltage for each circuit should be 9-14 volts.
2. If voltage is as specified, replace ECM. If voltage is not as specified, turn ignition off. Disconnect appropriate oxygen sensor connector. Using ohmmeter, measure resistance between terminals No. 1 and 2 at oxygen sensor connector. See «IDENTIFYING OXYGEN SENSOR HEATER TERMINALS»(ref-22530-S15556885492001010300000) table.
3. If resistance is 11-16 ohms at 68°F (20°C), check wiring harness between ECM and sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If resistance is not 11-16 ohms at 68°F (20°C), replace sensor.

1. If any other codes are displayed other than DTC P0136, diagnose and repair those codes first. If only DTC P0136 is displayed, check for open or short circuit in wiring harness between ECM and oxygen sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
2. If wiring harness is okay, connect scan tool. (Scheme 38) Start and warm engine to normal operating temperature. Monitor bank No. 1, sensor No. 2 output voltage. Snap accelerate engine to about 4000 RPM 3 times. Voltage should fluctuate from less than.4 volt to.5 volt or more.
3. If voltage fluctuates as specified, check oxygen sensor wiring harness connector. Problem may be intermittent. If voltage does not fluctuate as specified, replace sensor.

1. Access ECM behind glove box. Turn ignition on. On models with Calif. emissions and except Calif. emissions with engine immobilizer system and/or traction control, backprobe ECM connector and measure voltage between ground and terminal No. 9 (Pink/Black wire) at ECM E11 connector. (Scheme 40) On except Calif. emission models without engine immobilizer system and/or traction control, backprobe ECM connector and measure voltage between ground and terminal No. 17 (Pink/Black wire) at ECM E5 connector. (Scheme 41) NOTE: For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY/OPERATION article.
2. On all models, voltage should be 9-14 volts. If voltage is as specified, replace ECM. If voltage is not as specified, turn ignition off. Disconnect bank No. 1, sensor No. 2 connector. Connector is located underneath carpet on passenger's side, near center console. It may be necessary to remove passenger's seat to access connector. Using ohmmeter, measure resistance between terminals No. 1 (Pink/Black wire) and No. 2 (Light Green wire) at oxygen sensor connector.
3. If resistance is 11-16 ohms at 68°F (20°C), check wiring harness between ECM and oxygen sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If resistance is not 11-16 ohms at 68°F (20°C), replace oxygen sensor.

See DTC P0130 OR P0150 : HEATED OXYGEN SENSOR FAULT (EXCEPT CALIF. EMISSIONS) test.

See DTC P0133 OR P0153 : HEATED OXYGEN SENSOR SLOW RESPONSE (EXCEPT CALIF. EMISSIONS) test.

1. Check all air induction components. Repair as necessary. If air induction components are okay, connect scan tool. (Scheme 38) Start engine and warm to normal operating temperature. Monitor AFS output voltage and short-term fuel trim. If using OBD-II, scan tool, go to step 3). If using Toyota scan tool, go to next step.
2. If Toyota scan tool indicates a lean condition (.6 volt or less, +20 trim) or rich condition (.8 volt or more, -20 trim), go to step 4). If results are other than shown, check AFS. See appropriate SYSTEM/COMPONENT TESTS article.
3. If OBD-II scan tool indicates a lean condition (2.8 volts or less, +20 trim) or rich condition (3.8 volts or more, -20 trim), go to next step. If results are other than shown, check AFS. See appropriate SYSTEM/COMPONENT TESTS article.
4. Check fuel pressure. See appropriate BASIC TESTING article. Repair fuel pressure as necessary. If fuel pressure is okay, check fuel injectors. See appropriate SYSTEM/COMPONENT TESTS article. Replace injectors as necessary.
5. If all injectors are okay, check Mass Airflow (MAF) sensor and Engine Coolant Temperature (ECT) sensor. See appropriate SYSTEM/COMPONENT TESTS article. Replace components as necessary. If both components are okay, check ignition system. See IGNITION CHECKS in appropriate BASIC TESTING article. Repair ignition system as necessary. If ignition system is okay, replace ECM.

1. Check all air induction components. Repair as necessary. If air induction components are okay, connect scan tool. (Scheme 38) Start engine and warm to normal operating temperature. Monitor heated oxygen sensor output voltage and short-term fuel trim.
2. If scan tool indicates a lean condition (.6 volt or less, +20 trim) or rich condition (.4 volt or more, -20 trim), go to next step. If results are other than shown, see «DTC P0130 OR P0150»(ref-22530-S07054785842001010300000): HEATED OXYGEN SENSOR CIRCUIT (EXCEPT CALIF.) test.
3. Check fuel pressure. See appropriate BASIC TESTING article. Repair fuel pressure as necessary. If fuel pressure is okay, check fuel injectors. See appropriate SYSTEM/COMPONENT TESTS article. Replace injectors as necessary.
4. If all injectors are okay, check Mass Airflow (MAF) sensor and Engine Coolant Temperature (ECT) sensor. See appropriate SYSTEM/COMPONENT TESTS article. Replace components as necessary. If both components are okay, check ignition system. See IGNITION CHECKS in appropriate BASIC TESTING article. Repair ignition system as necessary. If ignition system is okay, go to next step.
5. Check exhaust system for leaks. Repair exhaust system as necessary. If exhaust system is okay, replace ECM.

Circuit Description

A misfire is determined by the ECM. The ECM uses signals provided by the crankshaft and camshaft position sensors. If the engine speed rate has changed enough to equal a preset number, a misfire is detected and the MIL is illuminated. If the misfire rate is high enough, and driving conditions will cause catalytic converter damage or overheating, the MIL blinks when a misfire is occurring.

DTC is set when misfiring of random cylinders is detected during any particular 200 or 1000 revolutions. Possible causes are

1. Ignition system.
2. Injector(s).
3. Fuel pressure.
4. EGR system.
5. Engine compression.
6. Valve clearance.
7. Valve timing.
8. Mass Airflow (MAF) sensor.
9. Engine Coolant Temperature (ECT) sensor.

1. Connect Toyota or OBD-II scan tool. (Scheme 38) Record any DTCs and freeze frame data. Switch scan tool to CHECK mode (Toyota scan tool only). Drive vehicle several times with engine speed, load and its surrounding range shown with ENGINE SPD, CALC LOAD in freeze frame data or MISFIRE RPM and MISFIRE LOAD in scan tool data list.
2. Drive vehicle at specified engine speeds. See «DRIVING PATTERN»(ref-22530-S14833777832001010300000) table. If using OBD-II scan tool, turn ignition off after symptom is simulated the first time, then repeat test drive again. If a misfire is detected, a DTC will set and misfire will be indicated in freeze frame data. Turn ignition off and wait a minimum of 5 seconds.

DRIVING PATTERN

1. Check vacuum hoses for leaks, blockage and proper routing. Also, check wiring harness and wiring harness connectors for damage or poor connections. Repair as necessary and perform TEST DRIVE CONFIRMATION. If vacuum hoses and wiring harness connectors are okay, go to next step.
2. Inspect spark plug and check for spark at misfiring cylinder. See appropriate BASIC TESTING article. Repair as necessary. If spark plug is okay and spark is present, go to next step.
3. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM connector. Measure voltage between ground and injector terminals at specified ECM connector. See appropriate «IDENTIFYING INJECTOR TERMINALS»(ref-22530-S35634367552001010300000) table. (Scheme 40)or (Scheme 41). If voltage is 9-14 volts for each circuit, go to step 5). If voltage is not 9-14 volts, go to next step. IDENTIFYING INJECTOR TERMINALS (MODELS WITH CALIF. EMISSIONS & EXCEPT CALIF. EMISSIONS WITH ENGINE IMMOBILIZER SYSTEM &/OR TRACTION CONTROL) Injector No. (1) Terminal No. Wire Color 1 (2) 5 White 2 (2) 6 Yellow 3 1 Black 4 2 Blue 5 3 Red 6 4 Green (1) Terminals are located in ECM E6 connector. (Scheme 40) (2) Check terminals at E7 connector. IDENTIFYING INJECTOR TERMINALS (EXCEPT CALIF. EMISSION MODELS WITHOUT ENGINE IMMOBILIZER SYSTEM &/OR TRACTION CONTROL) Injector No. (1) Terminal No. Wire Color 1 10 White 2 9 Yellow 3 8 Black 4 7 Blue 5 6 Red 6 5 Green (1) Terminals are located in ECM E8 connector. (Scheme 41)
4. Disconnect injector of misfiring cylinder. Using ohmmeter, measure resistance between injector terminals. If resistance is about 13.8 ohms, check for open or short circuit in wiring harness between ECM and injector. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If resistance is not about 13.8 ohms, replace injector.
5. Check fuel pressure. See appropriate BASIC TESTING article. Repair fuel pressure as necessary. If fuel pressure is okay, check fuel injector performance. See appropriate SYSTEM/COMPONENT TESTS article. Replace as necessary.
6. If all injectors are okay, check EGR system. See appropriate SYSTEM/COMPONENT TESTS article. Repair EGR system as necessary. If EGR system is okay, check MAF sensor and ECT sensor. See appropriate SYSTEM/COMPONENT TESTS article. Replace as necessary. If both components are okay, also check engine compression, valve clearance and valve timing. See appropriate BASIC TESTING article.

See DTC P0300 .: RANDOM MISFIRE DETECTED test.

See DTC P0300 : RANDOM MISFIRE DETECTED test.

1. Connect scan tool to DLC No. 3. (Scheme 38) Disconnect EC1 connector. EC1 connector is a wire-to-wire connector located under air intake chamber. EC1 connector is a 4-pin Dark Gray connector.
2. Remove, switch and install terminals No. 1 and 2 from male connector. (Scheme 42) Connect EC1 connector. Turn ignition on. Clear trouble codes. See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS -INTRODUCTION article. Start and warm engine to normal operating temperature.
3. Snap accelerate engine to about 4000 RPM 3 times. Retrieve trouble codes. See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article. If same code(s) are repeated as before, go to next step. If code(s) have changed, go to step 5).
4. Check for open or short circuit in wiring harness between EC1 connector and ECM. Repair wiring as necessary. If circuits are okay, replace ECM. Ensure EC1 male connector terminals are returned to their original position.
5. Check for open or short circuit in wiring harness between EC1 connector and knock sensor(s). To access harness, it may be necessary to remove intake manifold. See appropriate REMOVE/INSTALL/OVERHAUL article. Repair wiring as necessary. If wiring harness is okay, replace knock sensor. Ensure EC1 male connector terminals are returned to their original position.

Scheme 42

1. Disconnect CKP sensor connector. Using ohmmeter, measure resistance between CKP sensor connector terminals. Resistance should be 1630-2740 ohms (cold sensor) or 2065-3225 ohms (hot sensor).
2. Replace CKP sensor as necessary. If CKP sensor is okay, check for open or short circuit in wiring harness between ECM and CKP sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, remove and inspect CKP sensor. Also inspect signal plate. Replace CKP sensor and/or signal plate as necessary. If both components are okay, replace ECM.

1. Disconnect CMP sensor connector. Using ohmmeter, measure resistance between CMP sensor connector terminals. If resistance is not as specified, replace CMP sensor. See «CAMSHAFT POSITION SENSOR RESISTANCE»(ref-22530-S32444402792001010300000) table. If resistance is as specified, go to next step.
2. Check for open or short circuit in wiring harness between ECM and CMP sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, remove and inspect CMP sensor. Also inspect signal plate. Replace CMP sensor and/or signal plate as necessary. If both components are okay, replace ECM.

CAMSHAFT POSITION SENSOR RESISTANCE

1. Connect scan tool. (Scheme 38) Start and warm engine to normal operating temperature. Operate vehicle at 43-56 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes. Turn ignition off.
2. Start engine and allow to idle. Operate vehicle at 43-56 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes.
3. Using scan tool, check READINESS TESTS. If COMPL is displayed on scan tool and MIL is not illuminated, system is normal. If INCMPL is displayed and MIL is not illuminated, repeat test drive procedure.

Diagnosis & Repair (Using Toyota Scan Tool)

1. Connect scan tool. (Scheme 38) Start and run engine. Allow engine to reach normal operating temperature. Using scan tool, read EGR gas temperature. If temperature is 50-302°F (10-150°C), go to step 5). If temperature is not 50-302°F (10-150°C), go to next step. NOTE: If EGR gas temperature reading is 37.6°F (3.1°C), an open exists in EGR temperature sensor circuit. If temperature reading is 318.7°F (159.3°C), a short exists in EGR temperature sensor circuit.
2. Disconnect EGR temperature sensor connector. Sensor is mounted on manifold between EGR valve and air intake chamber. Connect a jumper wire between EGR temperature sensor connector terminals. Turn ignition on. If EGR temperature displayed is not 318.7°F (159.3°C), remove jumper wire and go to next step. If temperature displayed is 318.7°F (159.3°C), remove jumper wire. Recheck EGR temperature. If EGR temperature displayed is not 37.6°F (3.1°C), go to step 4). If temperature displayed is 37.6°F (3.1°C), check temperature sensor connector terminals. Repair as necessary. If connector is okay, replace sensor.
3. Turn ignition off. Access ECM behind glove box. On models with Calif. emissions and except Calif. emissions with engine immobilizer system and/or traction control, connect a jumper wire between terminals No. 13 (Green/Yellow wire) and No. 18 (Brown wire) at ECM E7 connector. (Scheme 40) On except Calif. emission models without engine immobilizer system and/or traction control, connect a jumper wire between terminal No. 14 (Green/Yellow wire) at ECM E6 connector and terminal No. 22 (Brown wire) at ECM E7 connector. (Scheme 41) On all models, turn ignition on. If EGR temperature displayed i s not 318.7°F (159.3°C), check ECM connectors. Repair as necessary. If connectors are okay, replace ECM. If temperature displayed is 318.7°F (159.3°C), locate and repair open in wiring harness between ECM and EGR temperature sensor. NOTE: For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY/OPERATION article.
4. Remove jumper wire. On models with Calif. emissions and except Calif. emissions with engine immobilizer system and/or traction control, disconnect ECM E7 connector. (Scheme 40) On except Calif. emission models without engine immobilizer system and/or traction control, disconnect ECM E6 connector. (Scheme 41) On all models, recheck EGR temperature. If EGR temperature displayed is not 37.6°F (3.1°C), check ECM connectors and repair as necessary. If connectors are okay, replace ECM. If temperature displayed is 37.6°F (3.1°C), locate and repair short in wiring harness between ECM and EGR temperature sensor.
5. Check all EGR system vacuum hoses. See appropriate illustration in VACUUM DIAGRAMS article. Repair vacuum hoses as necessary. If all hoses are okay, check EGR VSV. Using scan tool, select ACTIVE TEST mode. Check operation of VSV when activated by scan tool. VSV is located under "V" bank cover on top of engine.
6. Start and run engine. With EGR system off, air from port "E" should flow from port "G". (Scheme 43) With EGR system on, air from port "E". should flow from port "F". If valve operates as specified, go to step 8). If valve does not operate as specified, go to next step.
7. Remove EGR VSV. Using ohmmeter, measure resistance between VSV terminals. Resistance should be 27-33 ohms at 68°F (20°C). Measure resistance between each terminal and body of VSV. Resistance should be infinite. If resistance is not as specified, replace VSV. If resistance is as specified, go to next step.
8. Check VSV operation. Apply battery voltage to VSV terminals. Apply air pressure to VSV port "E". Air should flow from port "F". Remove battery voltage from valve terminals. Air should flow from port "G". Replace VSV as necessary. If VSV is okay, check for open in EGR VSV circuits between engine compartment fuse block and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary.
9. Perform EXHAUST GAS RECIRCULATION (EGR) SYSTEM TEST. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace components as necessary. If EGR system is functioning properly, check EGR Vacuum Control Valve (VCV). See appropriate SYSTEM/COMPONENT TESTS article. Replace as necessary. If VCV is okay, replace ECM.

Scheme 43

Diagnosis & Repair (Using OBD-II Scan Tool)

1. Disconnect EGR temperature sensor. Sensor is located on manifold between EGR valve and intake air chamber. Measure resistance between EGR temperature sensor terminals. If resistance is 2500-600,000 ohms, go to next step. If resistance is not 2500-600,000 ohms, replace EGR temperature sensor.
2. Check for open or short circuit in wiring harness between EGR temperature sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, go to next step.
3. Check all EGR system vacuum hoses. Replace hoses as necessary. If vacuum hoses are okay, access ECM behind glove box. Ensure ignition is off. On models with Calif. emissions and except Calif. emissions with engine immobilizer system and/or traction control, disconnect ECM E6 connector. (Scheme 40) Connect a jumper wire between ground and terminal No. 18 (Black/White wire) at ECM E6 connector. Go to next step. On except Calif. emission models without engine immobilizer system and/or traction control, disconnect ECM E6 connector. (Scheme 41) Connect a jumper wire between ground and terminal No. 12 (Black/White wire) at ECM E6 connector. Go to next step. NOTE: For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY/OPERATION article.
4. On all models, apply air pressure to EGR Vacuum Switching Valve (VSV) port "E". VSV is located under "V" bank cover on top of engine. With jumper wire connected, air should flow from port "F". (Scheme 43) With jumper wire disconnected, air should flow from port "G". If VSV operates as specified, go to step 7). If VSV does not operate as specified, go to next step.
5. Remove EGR VSV. Using ohmmeter, measure resistance between VSV terminals. Resistance should be 27-33 ohms at 68°F (20°C). Measure resistance between each terminal and body of VSV. Resistance should be infinite. If resistance is not as specified, replace VSV. If resistance is as specified, go to next step.
6. Check VSV operation. Apply battery voltage to VSV terminals. Apply air to VSV port "E". Air should flow from port "F". Remove battery voltage from VSV terminals. Air should flow from port "G". Replace VSV as necessary. If VSV is okay, check for open in EGR VSV circuits between fuse block in left side of engine compartment and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary.
7. Perform EXHAUST GAS RECIRCULATION (EGR) SYSTEM TEST. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace components as necessary. If EGR system is functioning properly, check EGR Vacuum Control Valve (VCV). See appropriate SYSTEM/COMPONENT TESTS article. Replace as necessary. If VCV is okay, replace ECM.

1. Connect scan tool. (Scheme 38) Start and warm engine to normal operating temperature. Operate vehicle at 43-56 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes. Turn ignition off.
2. Start engine and allow to idle. Operate vehicle at 43-56 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes.
3. Check READINESS TESTS. If COMPL is displayed on scan tool and MIL is not illuminated, system is normal. If INCMPL is displayed and MIL is not illuminated, repeat test drive procedure.

1. Check all EGR system vacuum hoses. See appropriate illustration in VACUUM DIAGRAMS article. Repair vacuum hoses as necessary. If all hoses are okay, check EGR VSV. Using scan tool, select ACTIVE TEST mode. Check operation of VSV when activated by scan tool. VSV is located under "V" bank cover on top of engine. Apply air pressure to VSV port "E". (Scheme 43) Go to next step.
2. With EGR system off, air from port "E" should flow from port "G". With EGR system on, air from port "E" should flow from port "F". If VSV operates as specified, go to step 5). If VSV does not operate as specified, go to next step.
3. Remove EGR VSV. Using ohmmeter, measure resistance between VSV terminals. Resistance should be 27-33 ohms at 68°F (20°C). Measure resistance between each terminal and body of VSV. Resistance should be infinite. If resistance is not as specified, replace VSV. If resistance is as specified, go to next step.
4. Check VSV operation. Apply battery voltage to VSV terminals. Apply air pressure to VSV port "E". Air should flow from port "F". Remove battery voltage from VSV terminals. Air should flow from port "G". Replace VSV as necessary. If VSV is okay, check for a short in EGR VSV circuits between EGR VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
5. Disconnect vacuum hose from EGR valve. Connect a vacuum pump to EGR valve. Start engine. Apply vacuum to EGR valve. If engine does not run rough or stall, replace EGR valve. If engine runs rough or stalls, check EGR valve position sensor. See appropriate SYSTEM/COMPONENT TESTS article. Replace position sensor as necessary. If EGR valve position sensor is okay, replace ECM.

1. Check all EGR system vacuum hoses. Replace hoses as necessary. If vacuum hoses are okay, access ECM behind glove box. Ensure ignition is off. On models with Calif. emissions and except Calif. emissions with engine immobilizer system and/or traction control, disconnect ECM E6 connector. (Scheme 40) Connect a jumper wire between ground and terminal No. 18 (Black/White wire) at ECM E6 connector. Go to next step. On except Calif. emission models without engine immobilizer system and/or traction control, disconnect ECM E6 connector. (Scheme 41) Connect a jumper wire between ground and terminal No. 12 (Black/White wire) at ECM E6 connector. Go to next step. NOTE: For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY/OPERATION article.
2. On all models, apply air pressure to EGR Vacuum Switching Valve (VSV) port "E". VSV is located under "V" bank cover on top of engine. (Scheme 43) With jumper wire connected, air should flow from port "F". With jumper wire disconnected, air should flow from port "G". If VSV operates as specified, go to step 5). If VSV does not operate as specified, go to next step.
3. Remove EGR VSV. Using ohmmeter, measure resistance between VSV terminals. Resistance should be 27-33 ohms at 68°F (20°C). Measure resistance between each terminal and body of VSV. Resistance should be infinite. If resistance is not as specified, replace VSV. If resistance is as specified, go to next step.
4. Check VSV operation. Apply battery voltage to VSV terminals. Apply air pressure to VSV port "E". (Scheme 43) Air should flow from port "F". Remove battery voltage from VSV terminals. Air should flow from port "G". Replace VSV as necessary. If VSV is okay, check for short in EGR VSV circuits between engine compartment fuse block and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
5. Disconnect vacuum hose from EGR valve. Connect a vacuum pump to EGR valve. Start engine. Apply vacuum to EGR valve. If engine does not run rough or stall, replace EGR valve. If engine runs rough or stalls, check EGR valve position sensor. See appropriate SYSTEM/COMPONENT TESTS article. Replace as necessary. If EGR position sensor is okay, replace ECM.

1. Connect scan tool. (Scheme 38) Start and warm engine to normal operating temperature. Drive vehicle at 31-40 MPH for 5-10 minutes. Stop vehicle. Retrieve codes. See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.
2. If codes other than P0420 are present, diagnose and repair those codes first. If only DTC P0420 is displayed, check AFS. See DTC P0125: INSUFFICIENT COOLANT TEMPERATURE FOR CLOSED LOOP FUEL CONTROL (CALIF. EMISSIONS). Repair as necessary. If AFS and AFS circuits are okay, go to next step.
3. Check heated oxygen sensor circuits. See «DTC P0136»(ref-22530-S32446810782001010300000): HEATED OXYGEN SENSOR CIRCUIT test. Repair as necessary. If heated oxygen sensor circuits are okay, replace catalytic converter.

1. Connect scan tool. (Scheme 38) Start and warm engine to normal operating temperature. Drive vehicle at 31-40 MPH for 5-10 minutes. Stop vehicle. Retrieve codes. See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.
2. If codes other than P0420 are present, diagnose and repair those codes first. If only DTC P0420 is displayed check bank No. 1, sensor No. 1 and bank No. 2, sensor No. 1 circuits. See «DTC P0130 OR P0150»(ref-22530-S07054785842001010300000): HEATED OXYGEN SENSOR FAULT (EXCEPT CALIF. EMISSIONS) test. Repair as necessary. If oxygen circuits are okay, go to next step.
3. Check bank No. 1, sensor No. 2 circuits. See «DTC P0136»(ref-22530-S32446810782001010300000): HEATED OXYGEN SENSOR CIRCUIT test. Repair as necessary. If oxygen circuits are okay, replace catalytic converter.

1. Check with vehicle driver if fuel tank cap was loose when refueling. If fuel tank cap was loose prior to refueling, it probably was cause of DTC to set. If fuel tank cap was not loose, check for cracks, deformations or loose connections in the following: Fuel tank. Charcoal canister. Fuel tank filler pipe. Hose and tubes around fuel tank and charcoal canister. Repair as necessary. If components are okay, go to next step.
2. Check if fuel tank cap is an original manufacturer's cap. If fuel tank cap is an original manufacturer's cap, go to next step. If fuel tank cap is not an original manufacturer's cap, replace cap with a manufacturer's cap.
3. Check if fuel cap is installed properly. Reinstall cap as necessary. If fuel cap is installed properly, go to next step.
4. Check for damaged fuel tank cap and gasket. Replace fuel cap as necessary. If fuel tank cap and gasket are okay, go to next step.
5. Remove fuel tank cap. Visually inspect fuel tank filler neck for damage. Replace filler neck as necessary. If filler neck is okay, go to next step.
6. Check vacuum hoses between vapor pressure sensor and VSV for vapor pressure sensor and between vapor pressure sensor and charcoal canister. Check hoses for correct installation, looseness and damage. Repair vacuum hoses as necessary. If vacuum hoses are okay, go to next step.
7. Check hose and tube between fuel tank and charcoal canister for correct installation and damage. Repair as necessary. If hose and tube are okay, go to next step.
8. Visually inspect charcoal canister for cracks or damage. Charcoal canister is located in left side of engine compartment. Replace canister as necessary. If canister is okay, go to next step.
9. Access ECM behind glove box. Turn ignition on. On models with Calif. emissions and except Calif. emissions with engine immobilizer system and/or traction control, backprobe ECM connector and measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (Brown wire) at ECM E7 connector. (Scheme 40) On except Calif. emission models without engine immobilizer system and/or traction control, backprobe ECM connector and measure voltage between terminals No. 1 (Blue/Red wire) and No. 22 (Brown wire) at ECM E7 connector. (Scheme 41) On all models, if voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM. NOTE: For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY/OPERATION article.
10. On models with Calif. emissions and except Calif. emissions with engine immobilizer system and/or traction control, backprobe ECM connector and measure voltage between terminal No. 17 (Pink wire) at ECM E12 connector and terminal No. 18 (Brown wire) at ECM E7 connector. (Scheme 40) On except Calif. emission models without engine immobilizer system and/or traction control, backprobe ECM connector and measure voltage between terminal No. 13 (Pink wire) at ECM E6 connector and terminal No. 22 (Brown wire) at ECM E7 connector. (Scheme 41) On all models, disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on firewall, near brake booster. Connect a vacuum pump to sensor. If voltage is 2.9-3.7 volts without vacuum applied and 1.3-2.1 volts with.59 in. Hg (2 kPa) applied, go to step 12). If voltage is not as specified, go to next step.
11. Check for an open or short in wiring harness between vapor pressure sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, replace vapor pressure sensor.
12. Disconnect vacuum hose from charcoal canister (vacuum hose from fuel tank-to-charcoal canister). Ensure fuel tank cap is installed properly. Using compressed air, apply.71 psi (.05 kg/cm 2 ) to disconnected vacuum hose. If fuel tank does not hold pressure for a minimum of one minute, replace fuel tank. If fuel tank holds pressure, no fault is indicated at this time. Probable cause of DTC to set was an incorrectly installed fuel tank cap.

Diagnosis & Repair (Using Toyota Scan Tool Models With Calif. Emissions & Except Calif. Emissions With Engine Immobilizer System &/Or Traction Control)

1. Check EVAP VSV, vapor pressure sensor VSV and vapor pressure sensor wiring harness connectors for damaged pins, corrosion and loose wires. For component locations, see appropriate illustration in THEORY/OPERATION article. Repair connectors as necessary. If connectors are okay, go to next step.
2. Check all EVAP related vacuum hoses for cracks, looseness and correct routing. For proper vacuum hose routing, see appropriate illustration in VACUUM DIAGRAMS article. Repair vacuum hoses as necessary. If vacuum hoses are okay, go to next step.
3. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (Brown wire) at ECM E7 connector. (Scheme 40) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
4. While backprobing ECM connector, measure voltage between terminal No. 17 (Pink wire) at ECM E12 connector and terminal No. 18 (Brown wire) at ECM E7 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on firewall, near brake booster. Connect a vacuum pump to sensor. If voltage is 2.9-3.7 volts without vacuum applied and 1.3-2.1 volts with.59 in. Hg (2 kPa) applied, go to step 6). If voltage is not as specified, go to next step.
5. Check for an open or short in wiring harness between vapor pressure sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, replace vapor pressure sensor.
6. Connect scan tool to DLC No. 3. Turn ignition. Using scan tool, select ACTIVE TEST mode. Disconnect EVAP VSV vacuum hose from charcoal canister. Start engine. Connect a vacuum gauge to disconnected vacuum hose. When EVAP VSV is activated by scan tool, vacuum should be present. When EVAP VSV is not activated, no vacuum should be present. If vacuum is as specified, go to step 9). If vacuum is not as specified, go to next step.
7. Check vacuum hose between intake manifold and EVAP VSV, and hose between EVAP VSV and charcoal canister. Replace vacuum hoses as necessary. If vacuum hoses are okay, check EVAP VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace VSV as necessary. If VSV is okay, go to next step.
8. Check for an open or short in wiring harness between EFI main relay, EVAP VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, replace ECM.
9. Turn ignition on. Using scan tool, select ACTIVE TEST mode. Locate vapor pressure sensor VSV on top of EVAP charcoal canister on left side of engine compartment. Apply air pressure to VSV port "E". (Scheme 43) When vapor pressure sensor VSV is activated by scan tool, air should flow from port "F". When VSV is not activated, air should flow from port "G". If VSV operates as specified, go to step 12). If VSV does not operate as specified, go to next step.
10. Check vapor pressure sensor VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace VSV as necessary. If VSV is okay, go to next step.
11. Check for open or short circuit in wiring harness between EFI main relay, vapor pressure sensor VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace ECM.
12. Disconnect vapor pressure sensor VSV connector. VSV is mounted on top of EVAP charcoal canister on left side of engine compartment. Start and run engine. Using scan tool, select ACTIVE TEST mode. Backprobing ECM connector, measure voltage between terminal No. 17 (Pink wire) at ECM E12 connector and terminal No. 18 (Brown wire) at ECM E7 connector. (Scheme 40) With EVAP VSV activated, voltage should be 2 volts or less. If voltage is as specified, go to step 14). If voltage is not as specified, go to next step.
13. Check vacuum hose between charcoal canister and vapor pressure sensor VSV, and vacuum hose between vapor pressure sensor and vapor pressure sensor VSV. Repair vacuum hoses as necessary. If vacuum hoses are okay, go to next step.
14. Remove fuel tank cap. Disconnect vapor pressure sensor VSV connector. Select ACTIVE TEST mode on scan tool. Start engine. Using scan tool, select ACTIVE TEST mode. Backprobing ECM connector, measure voltage between terminal No. 17 (Pink wire) at ECM E12 connector and terminal No. 18 (Brown wire) at ECM E7 connector 5 seconds after switch EVAP VSV from on to off. If voltage is 2.5 volts or less, replace charcoal canister. If voltage is more than 2.5 volts, go to next step.
15. Check charcoal canister. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace charcoal canister as necessary. If charcoal canister is okay, replace ECM.

Diagnosis & Repair (Using Toyota Scan Tool Except Calif. Emission Models Without Engine Immobilizer System &/Or Traction Control)

1. Check EVAP VSV, vapor pressure sensor VSV and vapor pressure sensor wiring harness connectors for damaged pins, corrosion and loose wires. Repair as necessary. If connectors are okay, go to next step. For component locations, see appropriate illustration in THEORY/OPERATION article.
2. Check all EVAP related vacuum hoses for cracks, looseness and correct routing. Repair vacuum hoses as necessary. If vacuum hoses are okay, go to next step. For proper vacuum hose routing, see appropriate illustration in VACUUM DIAGRAMS article.
3. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 1 (Blue/Red wire) and No. 22 (Brown wire) at ECM E7 connector. (Scheme 41) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
4. Backprobing ECM connector, measure voltage between terminal No. 13 (Pink wire) at ECM E6 connector and terminal No. 22 (Brown wire) at ECM E7 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on firewall, near brake booster. Connect a vacuum pump to sensor. If voltage is 2.9-3.7 volts without vacuum applied and 1.3-2.1 volts with.59 in. Hg (2 kPa) applied, go to step 6). If voltage is not as specified, go to next step.
5. Check for an open or short in wiring harness between vapor pressure sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, replace vapor pressure sensor.
6. Connect scan tool to DLC No. 3. Turn ignition. Using scan tool, select ACTIVE TEST mode. Disconnect EVAP VSV vacuum hose from charcoal canister. Start engine. Connect a vacuum gauge to disconnected vacuum hose. When EVAP VSV is activated by scan tool, vacuum should be present. When EVAP VSV is not activated, no vacuum should be present. If vacuum is as specified, go to step 9). If vacuum is not as specified, go to next step.
7. Check vacuum hose between intake manifold and EVAP VSV, and hose between EVAP VSV and charcoal canister. Replace vacuum hoses as necessary. If vacuum hoses are okay, check EVAP VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace VSV as necessary. If VSV is okay, go to next step.
8. Check for an open or short in wiring harness between EFI main relay, EVAP VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, replace ECM.
9. Turn ignition on. Using scan tool, select ACTIVE TEST mode. Locate vapor pressure sensor VSV on top of EVAP charcoal canister on left side of engine compartment. Apply air pressure to VSV port "E". (Scheme 43) When vapor pressure sensor VSV is activated by scan tool, air should flow from port "F". When VSV is not activated, air should flow from port "G". If VSV operates as specified, go to step 12). If VSV does not operate as specified, go to next step.
10. Check vapor pressure sensor VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace VSV as necessary. If VSV is okay, go to next step.
11. Check for open or short circuit in wiring harness between EFI main relay, vapor pressure sensor VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace ECM.
12. Disconnect vapor pressure sensor VSV connector. VSV is mounted on top of EVAP charcoal canister on left side of engine compartment. Start and run engine. Using scan tool, select ACTIVE TEST mode. Backprobing ECM connector, measure voltage between terminal No. 13 (Pink wire) at ECM E6 connector and terminal No. 22 (Brown wire) at ECM E7 connector. (Scheme 41) With EVAP VSV activated, voltage should be 2 volts or less. If voltage is as specified, go to step 14). If voltage is not as specified, go to next step.
13. Check vacuum hose between charcoal canister and vapor pressure sensor VSV, and vacuum hose between vapor pressure sensor and vapor pressure sensor VSV. Repair vacuum hoses as necessary. If vacuum hoses are okay, go to next step.
14. Remove fuel tank cap. Disconnect vapor pressure sensor VSV connector. Select ACTIVE TEST mode on scan tool. Start engine. Using scan tool, select ACTIVE TEST mode. Backprobing ECM connector, measure voltage between terminal No. 13 (Pink wire) at ECM E6 connector and terminal No. 22 (Brown wire) at ECM E7 connector 5 seconds after switching EVAP VSV from on to off. (Scheme 41) If voltage is 2.5 volts or less, replace charcoal canister. If voltage is more than 2.5 volts, go to next step.
15. Check charcoal canister. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace charcoal canister as necessary. If charcoal canister is okay, replace ECM.

Diagnosis & Repair (Using OBD-II Scan Tool Models With Calif. Emissions & Except Calif. Emissions With Engine Immobilizer System &/Or Traction Control)

1. Check EVAP VSV, vapor pressure sensor VSV and vapor pressure sensor wiring harness connectors for damaged pins, corrosion and loose wires. For component locations, see appropriate illustration in THEORY/OPERATION article. Repair connectors as necessary. If connectors are okay, go to next step.
2. Check all EVAP related vacuum hoses for cracks, looseness and correct routing. For proper vacuum hose routing, see appropriate illustration in VACUUM DIAGRAMS article. Repair vacuum hoses as necessary. If vacuum hoses are okay, go to next step.
3. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (Brown wire) at ECM E7 connector. (Scheme 40) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
4. Backprobing ECM connector, measure voltage between terminal No. 17 (Pink wire) at ECM E12 connector and terminal No. 18 (Brown wire) at ECM E7 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on firewall, near brake booster. Connect a vacuum pump to sensor. If voltage is 2.9-3.7 volts without vacuum applied and 1.3-2.1 volts with.59 in. Hg (2 kPa) applied, go to step 6). If voltage is not as specified, go to next step.
5. Check for an open or short in wiring harness between vapor pressure sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, replace vapor pressure sensor.
6. Disconnect EVAP VSV vacuum hoses. EVAP VSV is located on front top of engine. Apply air pressure to VSV port "E". (Scheme 44) Air should not flow from port "F". Access ECM behind glove box. Turn ignition on. Connect a jumper wire between ground and terminal No. 7 (Black/Red wire) at ECM E7 connector. (Scheme 40) Air should flow from port "F". If VSV functions as specified, go to step 9). If VSV does not function as specified, go to next step.
7. Check vacuum hose between intake manifold and EVAP VSV, and hose between EVAP VSV and charcoal canister. Replace vacuum hoses as necessary. If vacuum hoses are okay, check EVAP VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace VSV as necessary. If VSV is okay, go to next step.
8. Check for an open or short in wiring harness between EFI main relay, EVAP VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, replace ECM.
9. Disconnect vapor pressure sensor VSV vacuum hoses. VSV is mounted on top of EVAP charcoal canister on left side of engine compartment. Apply air pressure to VSV port "E". (Scheme 43) Air should flow from port "G". Access ECM behind glove box. Turn ignition on. Connect a jumper wire between ground and terminal No. 9 (White/Blue wire) at ECM E12 connector. (Scheme 40) Air should flow from port "F". If VSV does not function as specified, go to next step. If VSV functions as specified, check charcoal canister. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace charcoal canister as necessary.
10. Check vapor pressure sensor VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace VSV as necessary. If VSV is okay, go to next step.
11. Check for open or short circuit in wiring harness between EFI main relay, vapor pressure sensor VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness as necessary. If wiring harness is okay, replace ECM.

Scheme 44

Diagnosis & Repair (Using OBD-II Scan Tool Except Calif. Emission Models Without Engine Immobilizer System &/Or Traction Control)

1. Check EVAP VSV, vapor pressure sensor VSV and vapor pressure sensor wiring harness connectors for damaged pins, corrosion and loose wires. For component locations, see appropriate illustration in THEORY/OPERATION article. Repair connectors as necessary. If connectors are okay, go to next step.
2. Check all EVAP related vacuum hoses for cracks, looseness and correct routing. For proper vacuum hose routing, see appropriate illustration in VACUUM DIAGRAMS article. Repair vacuum hoses as necessary. If vacuum hoses are okay, go to next step.
3. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 1 (Blue/Red wire) and No. 22 (Brown wire) at ECM E7 connector. (Scheme 41) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
4. Backprobing ECM connector, measure voltage between terminal No. 13 (Pink wire) at ECM E6 connector and terminal No. 22 (Brown wire) at ECM E7 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on firewall, near brake booster. Connect a vacuum pump to sensor. If voltage is 2.9-3.7 volts without vacuum applied and 1.3-2.1 volts with.59 in. Hg (2 kPa) applied, go to step 6). If voltage is not as specified, go to next step.
5. Check for an open or short in wiring harness between vapor pressure sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, replace vapor pressure sensor.
6. Disconnect EVAP VSV vacuum hoses. EVAP VSV is located on front top of engine. Apply air pressure to VSV port "E". (Scheme 44) Air should not flow from port "F". Access ECM behind glove box. Turn ignition on. Connect a jumper wire between ground and terminal No. 2 (Black/Red wire) at ECM E6 connector. (Scheme 41) Air should flow from port "F". If VSV functions as specified, go to step 9). If VSV does not function as specified, go to next step.
7. Check vacuum hose between intake manifold and EVAP VSV, and hose between EVAP VSV and charcoal canister. Replace vacuum hoses as necessary. If vacuum hoses are okay, check EVAP VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace VSV as necessary. If VSV is okay, go to next step.
8. Check for an open or short in wiring harness between EFI main relay, EVAP VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, replace ECM.
9. Disconnect vapor pressure sensor VSV vacuum hoses. VSV is mounted on top of EVAP charcoal canister on left side of engine compartment. Apply air pressure to VSV port "E". (Scheme 43) Air should flow from port "G". Access ECM behind glove box. Turn ignition on. Connect a jumper wire between ground and terminal No. 8 (White/Blue wire) at ECM E6 connector. (Scheme 41) Air should flow from port "F". If VSV does not function as specified, go to next step. If VSV functions as specified, check charcoal canister. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace charcoal canister as necessary.
10. Check vapor pressure sensor VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace VSV as necessary. If VSV is okay, go to next step.
11. Check for open or short circuit in wiring harness between EFI main relay, vapor pressure sensor VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness as necessary. If wiring harness is okay, replace ECM.

1. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (Brown wire) at ECM E7 connector. (Scheme 40) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
2. Backprobing ECM connector, measure voltage between terminal No. 17 (Pink wire) at ECM E12 connector and terminal No. 18 (Brown wire) at ECM E7 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on firewall, near brake booster. Connect a vacuum pump to sensor. If voltage is 2.9-3.7 volts without vacuum applied and 1.3-2.1 volts with.59 in. Hg (2 kPa) applied, replace ECM. If voltage is not as specified, go to next step.
3. Check for open or short circuit in wiring harness between vapor pressure sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace vapor pressure sensor.

1. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 1 (Blue/Red wire) and No. 22 (Brown wire) at ECM E7 connector. (Scheme 41) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
2. Backprobing ECM connector, measure voltage between terminal No. 13 (Pink wire) at ECM E6 connector and terminal No. 22 (Brown wire) at ECM E7 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on firewall, near brake booster. Connect a vacuum pump to sensor. If voltage is 2.9-3.7 volts without vacuum applied and 1.3-2.1 volts with.59 in. Hg (2 kPa) applied, replace ECM. If voltage is not as specified, go to next step.
3. Check for open or short circuit in wiring harness between vapor pressure sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace vapor pressure sensor.

1. Test drive vehicle and check operation of speedometer. If speedometer is not functioning correctly, see INSTRUMENT PANEL article in ACCESSORIES/SAFETY EQUIPMENT Section. If speedometer is functioning correctly, go to next step.
2. Access ECM behind glove box. Ensure ignition is off. Disconnect ECM E11 connector. (Scheme 40) Using ohmmeter, check continuity between ground and terminal No. 22 (Violet wire) at ECM E11 connector. If continuity exists, locate and repair short circuit. If continuity does not exist, go to next step.
3. Turn ignition on. Using DVOM, measure voltage between ground and terminal No. 22 (Violet wire) at ECM E11 connector. If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check for open in Violet wire. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
4. Check for open circuit in wiring harness between instrument cluster and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace ECM.

1. Test drive vehicle and check operation of speedometer. If speedometer is not functioning correctly, see INSTRUMENT PANEL article in ACCESSORIES/SAFETY EQUIPMENT Section. If speedometer is functioning correctly, go to next step.
2. Access ECM behind glove box. Ensure ignition is off. Disconnect ECM E5 connector. (Scheme 41) Using ohmmeter, check continuity between ground and terminal No. 12 (Violet wire) at ECM E5 connector. If continuity exists, locate and repair short circuit. If continuity does not exist, go to next step.
3. Turn ignition on. Using DVOM, measure voltage between ground and terminal No. 12 (Violet wire) at ECM 5 connector. If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check for open in Violet wire. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
4. Check for open circuit in wiring harness between instrument cluster and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace ECM.

Repair & Diagnosis (Models With Calif. Emissions & Except Calif. Emissions With Engine Immobilizer System &/Or Traction Control)

1. Ensure engine is at normal operating temperature and all accessories are off. Ensure A/C is off. Shift transaxle lever into Neutral position. Connect scan tool to DLC No. 3. (Scheme 38) Note engine RPM. Using a jumper wire, connect terminals TE1 and E1 at DLC No. 1 in engine compartment. (Scheme 45) Note engine RPM and compare RPM readings. If difference in engine speed is more than 100 RPM, go to step 6). If difference in engine speed is 100 RPM or less, go to next step.
2. Ensure ignition is off. Access ECM behind glove box. Disconnect ECM E6 connector. (Scheme 40) Turn ignition on. Measure voltage between ground and terminals No. 15 (Yellow/Black wire) and No. 16 (Red/White wire) at ECM E6 connector. If both readings are 9-14 volts, go to step 4). If any reading is not 9-14 volts, go to next step.
3. Turn ignition off. Disconnect IAC valve connector. IAC valve is located in front of throttle body at 6 o'clock position. Using ohmmeter, measure resistance between terminal No. 2 and terminals No. 1 and 3 at IAC valve. (Scheme 46) If resistance is not 17-25 ohms (cold) or 22-29 ohms (hot), replace IAC valve. If resistance is 17-25 ohms (cold) or 22-29 ohms (hot), check for an open or short in wiring harness between IAC valve and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
4. Check IAC valve operation. See IDLE CONTROL SYSTEM in appropriate SYSTEM/COMPONENT TESTS article. Replace IAC valve as necessary. If valve is okay, go to next step.
5. Remove IAC valve from throttle body. Check IAC valve for carbon build-up and blockage. Repair or replace IAC valve as necessary. If IAC valve is okay, replace ECM.
6. Check air induction system for leaks. Repair air induction system as necessary. If air induction system is okay, an open or short in A/C switch signal circuit may exist. Check A/C amplifier. See appropriate article in AIR CONDITIONING & HEATING section. Repair as necessary.

Scheme 45

Scheme 46

Repair & Diagnosis (Except Calif. Emission Models Without Engine Immobilizer System &/Or Traction Control)

1. Ensure engine is at normal operating temperature and all accessories are off. Ensure A/C is off. Shift transaxle lever into Neutral position. Connect scan tool to DLC No. 3. (Scheme 38) Note engine RPM. Using a jumper wire, connect terminals TE1 and E1 at DLC No. 1 in engine compartment. (Scheme 45) Note engine RPM and compare RPM readings. If difference in engine speed is more than 100 RPM, go to step 6). If difference in engine speed is 100 RPM or less, go to next step.
2. Ensure ignition is off. Access ECM behind glove box. Disconnect ECM E8 connector. (Scheme 41) Turn ignition on. Measure voltage between ground and terminals No. 22 (Yellow/Black wire) and No. 23 (Red/White wire) at ECM E8 connector. If both readings are 9-14 volts, go to step 4). If any reading is not 9-14 volts, go to next step.
3. Turn ignition off. Disconnect IAC valve connector. IAC valve is located in front of throttle body at 6 o'clock position. Using ohmmeter, measure resistance between terminal No. 2 and terminals No. 1 and 3 at IAC valve. (Scheme 46) If resistance is not 17-25 ohms (cold) or 22-29 ohms (hot), replace IAC valve. If resistance is 17-25 ohms (cold) or 22-29 ohms (hot), check for an open or short in wiring harness between IAC valve and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
4. Check IAC valve operation. See IDLE CONTROL SYSTEM in appropriate SYSTEM/COMPONENT TESTS article. Replace IAC valve as necessary. If valve is okay, go to next step.
5. Remove IAC valve from throttle body. Check IAC valve for carbon build-up and blockage. Repair or replace IAC valve as necessary. If IAC valve is okay, replace ECM.
6. Check air induction system for leaks. Repair air induction system as necessary. If air induction system is okay, an open or short in A/C switch signal circuit may exist. Check A/C amplifier. See appropriate article in AIR CONDITIONING & HEATING section. Repair as necessary.

1. If using OBD-II scan tool, go to next step. If using Toyota scan tool, connect scan tool. (Scheme 38) Switch scan tool to CHECK mode. Start and warm engine to normal operating temperature. Drive vehicle at 38-65 MPH with engine speed at 1600-3200 RPM for 3-5 minutes. If malfunction exists, MIL will illuminate.
2. If using OBD-II scan tool, start and warm engine to normal operating temperature. Drive vehicle at 38-65 MPH with engine speed at 1600-3200 RPM for 3-5 minutes. Stop vehicle and turn ignition off. Repeat driving part of test. If malfunction exists, MIL will illuminate.

1. If only DTC P1130 or P1150 is displayed, go to next step. If other codes are displayed, diagnose and repair those codes first and retest system.
2. Disconnect suspect AFS connector. One AFS is located in each exhaust manifold. Using ohmmeter, measure resistance between Blue wire and Blue/Red wire (bank No. 1) or between Blue wire and Black/Red wire (bank No. 2) at AFS connector. Resistance should be .8-1.4 ohms at 68°F (20°C). Replace AFS as necessary. If resistance is .8-1.4 ohms, go to next step.
3. Reconnect AFS connector. Start engine and raise engine speed to 2500 RPM for 90 seconds. Using scan tool, monitor AFS output voltage. See «AIR/FUEL RATIO SENSOR SPECIFICATIONS»(ref-22530-S07302566212001010300000) table. If voltage is as specified, go to step 5). If voltage is not as specified, go to next step.
4. Check for open or short circuit in wiring harness between ECM and AFS. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace AFS.
5. Perform TEST DRIVE CONFIRMATION. If DTC P1130 or P1150 resets, replace ECM. If DTC P1130 or P1150 does not reset, no problem is indicated at this time.

1. If using OBD-II scan tool, go to next step. If using Toyota scan tool, connect scan tool. (Scheme 38) Switch scan tool to CHECK mode. Start and warm engine to normal operating temperature. Drive vehicle at 38-65 MPH with engine speed at 1600-3200 RPM for 3-5 minutes. If malfunction exists, MIL will illuminate.
2. If using OBD-II scan tool, start and warm engine to normal operating temperature. Drive vehicle at 38-65 MPH with engine speed at 1600-3200 RPM for 3-5 minutes. Stop vehicle and turn ignition off. Repeat driving part of test. If malfunction exists, MIL will illuminate.

1. If only DTC P1133 or P1153 is displayed, go to next step. If other codes are displayed, diagnose and repair those codes first and retest system.
2. Disconnect AFS connector. One AFS is located in each exhaust manifold. Using ohmmeter, measure resistance between Blue wire and Blue/Red wire (bank No. 1) or between Blue wire and Black/Red wire (bank No. 2) at AFS connector. Resistance should be .8-1.4 ohms at 68°F (20°C). Replace AFS as necessary. If resistance is .8-1.4 ohms, go to next step.
3. Perform TEST DRIVE CONFIRMATION. If DTC P1133 or P1153 resets, replace AFS. If DTC P1133 or P1153 does not reset, no problem is indicated at this time.

1. Access ECM behind glove box. Turn ignition on. Measure voltage between ground and terminals No. 4 (Black/Red wire) and No. 3 (Blue/Red wire) at ECM connector E7. (Scheme 40) If voltage is 9-14 volts, replace ECM. If voltage is not 9-14 volts, go to next step.
2. Disconnect suspect AFS connector. One AFS is located in each exhaust manifold. Using ohmmeter, measure resistance between Blue wire and Blue/Red wire (bank No. 1) or between Blue wire and Black/Red wire (bank No. 2) at AFS connector. Resistance should be.8-1.4 ohms at 68°F (20°C). Replace AFS as necessary. If resistance is.8-1.4 ohms, go to next step.
3. Check for open or short circuit in wiring harness between EFI main relay, AFS and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary.

1. Check for spark at misfiring cylinder. See IGNITION CHECKS in appropriate BASIC TESTING article. If spark is present, go to next step. If spark is not present, go to step 4).
2. Check for open or short between terminal No. 25 (White/Red wire) at ECM E6 connector and ignitor. (Scheme 40) Ignitor is located near left shock tower. Repair wiring as necessary. If wiring is okay, go to next step.
3. Disconnect Black 10-pin ignitor connector. Access ECM behind glove box. Turn ignition on. Measure voltage between ground and terminal No. 25 (White/Red wire) at ECM E6 connector. (Scheme 40) If voltage is 4.5-5.5 volts, replace ignitor. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in IGT1, IGT2 and IGT3 circuits between ECM and ignitor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary. If circuits are okay, go to next step.
5. Access ECM behind glove box. Locate ECM E6 connector. (Scheme 40) Backprobing ECM connector, measure voltage between ground and terminals No. 13 (Green/Red wire), No. 12 (Yellow/Red wire) and No. 11 (Gray wire) at ECM E6 connector while cranking engine. If all readings are.1-4.5 volts, go to next step. If any reading is not.1-4.5 volts, replace ECM.
6. Disconnect ignitor Black 10-pin connector. Backprobing ECM connector, measure voltage between ground and terminals No. 13 (Green/Red wire), No. 12 (Yellow/Red wire) and No. 11 (Gray wire) at ECM E6 connector while cranking engine. If all readings are.1-4.5 volts, go to next step. If any reading is not.1-4.5 volts, replace ECM.
7. Turn ignition on. Measure voltage between ground and terminal No. 9 (Black/Red wire) at ignitor wiring harness connector. (Scheme 47) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignitor power source circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
8. Check for an open or short in wiring harness between ignition switch and ignition coil, and between ignition coil and ignitor. Repair wiring as necessary. If wiring is okay, go to next step.
9. Check ignition coil. See IGNITION CHECKS in appropriate BASIC TESTING article. Replace coil as necessary. If coil is okay, go to next step.
10. Check EFI main relay. See appropriate SYSTEM/COMPONENT TESTS article. Replace relay as necessary. If relay is okay, replace ignitor.

Scheme 47

1. Check for spark at misfiring cylinder. See IGNITION CHECKS in appropriate BASIC TESTING article. If spark is present, go to next step. If spark is not present, go to step 4).
2. Check for open or short between terminal No. 12 (White/Red wire) at ECM E8 connector and ignitor. (Scheme 41) Ignitor is located near left shock tower. Repair wiring as necessary. If wiring is okay, go to next step.
3. Disconnect Black 10-pin ignitor connector. Access ECM behind glove box. Turn ignition on. Measure voltage between ground and terminal No. 12 (White/Red wire) at ECM E10 connector. (Scheme 41) If voltage is 4.5-5.5 volts, replace ignitor. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in IGT1, IGT2 and IGT3 circuits between ECM and ignitor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary. If circuits are okay, go to next step.
5. Access ECM behind glove box. Locate ECM E8 connector. (Scheme 41) Backprobing ECM connector, measure voltage between ground and terminals No. 15 (Green/Red wire), No. 16 (Yellow/Red wire) and No. 24 (Gray wire) at ECM E8 connector while cranking engine. If all readings are.1-4.5 volts, go to next step. If any reading is not.1-4.5 volts, replace ECM.
6. Disconnect ignitor Black 10-pin connector. Backprobing ECM connector, measure voltage between ground and terminals No. 15 (Green/Red wire), No. 16 (Yellow/Red wire) and No. 24 (Gray wire) at ECM E8 connector while cranking engine. If all readings are.1-4.5 volts, go to next step. If any reading is not.1-4.5 volts, replace ECM.
7. Turn ignition on. Measure voltage between ground and terminal No. 9 (Black/Red wire) at ignitor wiring harness connector. (Scheme 47) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignitor power source circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
8. Check for an open or short in wiring harness between ignition switch and ignition coil, and between ignition coil and ignitor. Repair wiring as necessary. If wiring is okay, go to next step.
9. Check ignition coil. See IGNITION CHECKS in appropriate BASIC TESTING article. Replace coil as necessary. If coil is okay, go to next step.
10. Check EFI main relay. See appropriate SYSTEM/COMPONENT TESTS article. Replace relay as necessary. If relay is okay, replace ignitor.

1. Disconnect EGR valve vacuum hose. Disconnect EGR valve position sensor connector. Turn ignition on. Measure voltage between ground and Blue/Red wire at EGR valve position sensor wiring harness connector. If voltage is 4.5-5.5 volts, go to step 4). If voltage is not 4.4-5.5 volts, go to next step.
2. Measure resistance between terminals No. 1 (Blue/Red wire) and No. 2 (Brown wire) at EGR valve position sensor. If resistance is 1500-4300 ohms, go to next step. If resistance is not 1500-4300 ohms, replace EGR valve position sensor.
3. Connect vacuum pump to EGR valve. Access ECM behind glove box. Backprobing ECM connector, measure voltage between terminals No. 18 (Brown wire) at ECM E7 connector and No. 22 (Red/White wire) at ECM E6 connector. (Scheme 40) With no vacuum applied, voltage should be.4-1.6 volt. With vacuum applied, voltage should be 3.2-5.1 volts. If voltage is as specified, replace ECM. If voltage is not as specified, check for an open or short in wiring harness between ECM and EGR valve position sensor. Repair wiring as necessary.
4. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 18 (Brown wire) and No. 2 (Blue/Red wire) at ECM E7 connector. If voltage is 4.5-5.5 volts, check for an open or short in wiring harness between ECM and EGR valve position sensor. Repair wiring as necessary. If voltage is 4.5-5.5 volts, replace ECM.

1. Disconnect EGR valve vacuum hose. Disconnect EGR valve position sensor connector. Turn ignition on. Measure voltage between ground and Blue/Red wire at EGR valve position sensor wiring harness connector. If voltage is 4.5-5.5 volts, go to step 4). If voltage is not 4.4-5.5 volts, go to next step.
2. Measure resistance between terminals No. 1 (Blue/Red wire) and No. 2 (Brown wire) at EGR valve position sensor. If resistance is 1500-4300 ohms, go to next step. If resistance is not 1500-4300 ohms, replace EGR valve position sensor.
3. Connect vacuum pump to EGR valve. Access ECM behind glove box. Backprobing ECM connector, measure voltage between terminals No. 22 (Brown wire) at ECM E7 connector and No. 15 (Red/White wire) at ECM E6 connector. (Scheme 41) With no vacuum applied, voltage should be.4-1.6 volt. With vacuum applied, voltage should be 3.2-5.1 volts. If voltage is as specified, replace ECM. If voltage is not as specified, check for an open or short in wiring harness between ECM and EGR valve position sensor. Repair wiring as necessary.
4. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 22 (Brown wire) and No. 1 (Blue/Red wire) at ECM E7 connector. If voltage is 4.5-5.5 volts, check for an open or short in wiring harness between ECM and EGR valve position sensor. Repair wiring as necessary. If voltage is 4.5-5.5 volts, replace ECM.

If only DTC P1411 is displayed, replace EGR valve position sensor. If other codes are displayed, diagnose and repair those codes first and retest system.

1. Check stoplights. If stoplights do not function properly, repair as necessary and retest system. If stoplights function properly, go to next step.
2. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between ground and terminal No. 15 (Green/White wire) at ECM E12 connector. (Scheme 40) With brake pedal depressed, voltage should be 7.5-14.0 volts. With brake pedal released, voltage should be less than 1.5 volt. If voltage is not as specified, go to next step. If voltage is as specified, check wiring harness and connectors. Problem is intermittent.
3. Check for short in wiring harness between ECM and stoplight switch. Repair wiring as necessary. If wiring harness is okay, replace ECM. Retest system.

1. Check stoplights. If stoplights do not function properly, repair as necessary and retest system. If stoplights function properly, go to next step.
2. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between ground and terminal No. 24 (Green/White wire) at ECM E5 connector. (Scheme 41) With brake pedal depressed, voltage should be 7.5-14.0 volts. With brake pedal released, voltage should be less than 1.5 volt. If voltage is not as specified, go to next step. If voltage is as specified, check wire harness and connectors. Problem is intermittent.
3. Check for short in wiring harness between ECM and stoplight switch. Repair wiring as necessary. If wiring harness is okay, replace ECM. Retest system.

1. Turn ignition off. Access ECM behind glove box. Backprobing ECM connector, measure voltage between ground and terminal No. 1 (Black/Yellow wire) at ECM E12 connector. (Scheme 40)If voltage is 9-14 volts, replace ECM. If voltage is not 9-14 volts, go to next step.
2. Remove and inspect EFI fuse. EFI fuse is located in engine compartment fuse box. If fuse is blown, check for short to ground in wiring harness. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary and replace fuse. If fuse is okay, check circuit between EFI fuse and ECM. Repair as necessary.

1. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between ground and specified terminal at ECM E11 connector. See «PARK/NEUTRAL POSITION SWITCH VOLTAGE (MODELS WITH CALIF»(ref-22530-S23802191912001010300000). EMISSIONS & EXCEPT CALIF. EMISSIONS WITH ENGINE IMMOBILIZER SYSTEM &/OR TRACTION CONTROL) table. (Scheme 40) If voltage is as specified, no problem is indicated at this time. If voltage is not as specified, go to next step. PARK/NEUTRAL POSITION SWITCH VOLTAGE (MODELS WITH CALIF. EMISSIONS & EXCEPT CALIF. EMISSIONS WITH ENGINE IMMOBILIZER SYSTEM &/OR TRACTION CONTROL) Shifter Position (1) Terminal No. Volts Park & Neutral 2 Zero " 3 Zero " 12 Zero " 20 Zero Reverse 2 9-14 " 3 Zero " 12 Zero " 20 9-14 Drive 2 Zero " 3 Zero " 12 Zero " 20 9-14 2 2 Zero " 3 9-14 " 12 Zero " 20 9-14 Low 2 Zero " 3 Zero " 12 9-14 " 20 9-14 (1) Measure voltage between ground and terminal listed at ECM E11 connector. (Scheme 40)
2. Disconnect PNP switch connector. Using ohmmeter, check continuity of switch terminals in specified positions. See «PARK/NEUTRAL POSITION SWITCH CONTINUITY»(ref-22530-S30087451012001010300000) table. (Scheme 48) Replace switch as necessary. If switch is okay, check wiring harness between battery and PNP switch and between PNP switch and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace ECM.

PARK/NEUTRAL POSITION SWITCH CONTINUITY

Scheme 48

1. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between ground and specified terminal at ECM E5 or E8 connector. See PARK/NEUTRAL POSITION SWITCH VOLTAGE (MODELS WITHOUT CALIF. EMISSIONS & ENGINE IMMOBILIZER SYSTEM &/OR TRACTION CONTROL) table. (Scheme 41) If voltage is as specified, no problem is indicated at this time. If voltage is not as specified, go to next step. PARK/NEUTRAL POSITION SWITCH VOLTAGE (EXCEPT CALIF. EMISSION MODELS WITHOUT ENGINE IMMOBILIZER SYSTEM &/OR TRACTION CONTROL) Shifter Position (1) Terminal No. Volts Park & Neutral 1 Zero " 10 Zero " (2) 14 Zero " 15 Zero Reverse 1 Zero " 10 Zero " (2) 14 9-14 " 15 9-14 Drive 1 Zero " 10 Zero " (2) 14 9-14 " 15 Zero 2 1 Zero " 10 9-14 " (2) 14 9-14 " 15 Zero Low 1 9-14 " 10 Zero " (2) 14 9-14 " 15 Zero (1) Measure voltage between ground and terminal listed at ECM E5 connector. (2) Measure voltage between ground and terminal No. 14 at ECM E8 connector.
2. Disconnect PNP switch connector. Using ohmmeter, check continuity of switch terminals in specified positions. See «PARK/NEUTRAL POSITION SWITCH CONTINUITY»(ref-22530-S30087451012001010300000) table. (Scheme 48) Replace switch as necessary. If switch is okay, check wiring harness between battery and PNP switch and between PNP switch and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace ECM.