Engine Control System Self-Diagnostics - 4-CYLINDER: Diagnosis Toyota Highlander I

MALFUNCTION INDICATOR LIGHT INSPECTION

Note. Malfunction Indicator Light (MIL) may also be referred to as CHECK ENGINE light. Inspect MIL to ensure it is operational and will come on if a Diagnostic Trouble Code (DTC) is set.

1. Turn ignition on. Check that MIL comes on and remains on. MIL is displayed as an engine icon just to the left of the trip meter reset knob on the tachometer on instrument panel. If MIL comes on, go to next step. If MIL does not come on, check bulb circuit on instrument cluster and wiring circuit between MIL and ECM. See «WIRING DIAGRAMS»(ref-133228) article. See «ENGINE CONTROL MODULE LOCATION»(ref-133207-S39056765572002021900000) .
2. Start engine and ensure MIL goes off. If MIL goes off, no malfunction is detected at this time. If MIL remains on or blinks with engine running, a malfunction is detected. Proceed to «TESTING PROCEDURE»(ref-133207-S04331788452002021900000) .

TESTING PROCEDURE

To ensure correct diagnosis and repair, testing should be done in the following sequence

1. Record Customer Complaint Ensure all customer complaints or observations are recorded. Test drive vehicle with customer when necessary for malfunction verification.
2. Retrieve Diagnostic Trouble Codes Using Toyota hand-held tester or scan tool, retrieve Diagnostic Trouble Codes (DTC) from Engine Control Module (ECM) and record any freeze frame data (if applicable). See «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-133207-S28744385952002021900000) .
3. Clear Diagnostic Trouble Codes Using Toyota hand-held tester or scan tool, clear DTCs and freeze frame data from ECM. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-133207-S20923646992002021900000) .
4. Visual Inspection Inspect all electrical connectors and wiring for suspected circuit or component. Ensure all electrical connections are clean and tight.
5. Confirm Symptoms & Diagnostic Trouble Codes Perform road test. Determine if original symptoms still exist. Using scan tool or Toyota hand-held tester, retrieve DTCs from ECM. See «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-133207-S28744385952002021900000) .
6. Diagnose & Repair Diagnostic Trouble Codes Perform appropriate DTC test listed under DIAGNOSTIC TESTS as necessary. For DTC descriptions, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-133207-S33147453882002021900000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If no DTCs are present and a no start condition exists, proceed to «BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER»(ref-133196) article. If no DTCs are present and a driveability condition exists, proceed to «TROUBLE SHOOTING - NO CODES»(ref-133220) article for diagnosis by symptom (i.e., ROUGH IDLE, ENGINE STALLS, etc.).
7. Verification Procedure After repairs have been completed, clear all DTCs from ECM. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-133207-S20923646992002021900000) . Perform road test. Ensure no DTCs exist and all symptoms and/or complaints have been repaired.

RETRIEVING DIAGNOSTIC TROUBLE CODES

Note. Diagnostic Trouble Codes (DTC) may be retrieved using Toyota hand-held tester or On-Board Diagnostic (OBD-II) scan tool that complies with SAE standard J-1978. Toyota hand-held tester or OBD-II scan tool may be operated in NORMAL mode when retrieving DTCs. Only Toyota hand-held tester may be used in CHECK mode when retrieving DTCs.

NORMAL mode is used to retrieve DTCs from Engine Control Module (ECM). CHECK mode is used to check for DTCs when operating vehicle to simulate conditions during which DTC was set. CHECK mode contains a higher sensing ability to detect malfunctions. CHECK mode helps determine malfunctions caused by poor electrical connections or intermittent problems which are difficult to determine using NORMAL mode.

Note. If using Toyota hand-held tester, when ignition switch is turned from ON to ACC or OFF position, hand-held tester is switched from NORMAL mode to CHECK mode or from CHECK MODE to NORMAL mode, all DTCs and freeze frame data will be erased from ECM. DO NOT switch modes until all DTCs and freeze frame data have been recorded.

NORMAL Mode Diagnostic Trouble Code Retrieval

1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on with engine off. Turn hand-held tester or scan tool on. Using hand-held tester or scan tool manufacturer's instructions, check for DTCs and freeze frame data.
2. If hand-held tester or scan tool does not display UNABLE TO CONNECT TO VEHICLE, go to next step. If hand-held tester or scan tool displays UNABLE TO CONNECT TO VEHICLE, see «DATA LINK CONNECTOR NO. 3 INSPECTION»(ref-133207-S29721248932002021900000) under SCAN TOOL PROBLEMS.
3. Record any DTCs and freeze frame data displayed for system diagnosis. If driveability problem exist and no DTCs are present, go to «TROUBLE SHOOTING - NO CODES»(ref-133220) article for diagnosis by symptom.
4. If any DTCs are present, perform appropriate DTC test under «DIAGNOSTIC TESTS»(ref-133207-S17242210612002021900000). For DTC descriptions, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-133207-S33147453882002021900000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. For more information on freeze frame data, see «FREEZE FRAME DATA»(ref-133207-S35946108712002021900000). For information on two-trip detection logic codes, see «TWO-TRIP DETECTION LOGIC»(ref-133207-S00275192152002021900000).
5. After repairs for DTC have been completed, DTC must be cleared from ECM. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-133207-S20923646992002021900000). Road test vehicle to ensure all symptoms and/or complaints have been repaired.

CHECK Mode Diagnostic Trouble Code Retrieval (Toyota Hand-Held Tester Only)

Note. If using Toyota hand-held tester, if ignition switch is turned from ON to ACC or OFF position during CHECK mode, all DTCs and freeze frame data will be erased from ECM. DO NOT switch from CHECK mode to NORMAL mode until all DTCs and freeze frame data are recorded.

1. Ensure vehicle battery is fully charged. Apply parking brake. Shift transaxle into Neutral (M/T) or Park (A/T). Turn A/C and all accessories off. Ensure throttle valve is fully closed. Turn ignition off. Connect hand-held tester to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on and then turn hand-held tester on.
2. Switch hand-held tester from NORMAL mode to CHECK mode. Ensure Malfunction Indicator Light (MIL) on instrument cluster flashes to indicate CHECK mode operation. Start engine. If no DTCs are present, MIL will turn off. Try to simulate conditions of driveability complaint described by customer.
3. Record any DTCs and freeze frame data displayed for system diagnosis. If driveability problem exist and no DTCs are present, go to «TROUBLE SHOOTING - NO CODES»(ref-133220) article for diagnosis by symptom.
4. If any DTCs are present, perform appropriate DTC test under «DIAGNOSTIC TESTS»(ref-133207-S17242210612002021900000). For DTC description, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-133207-S33147453882002021900000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. For information on freeze frame data, see «FREEZE FRAME DATA»(ref-133207-S35946108712002021900000). For information on two-trip detection logic codes, see «TWO-TRIP DETECTION LOGIC»(ref-133207-S00275192152002021900000).
5. After repairs for DTC have been completed, DTC must be cleared from ECM. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-133207-S20923646992002021900000). Road test vehicle to ensure all symptoms and/or complaints have been repaired.

CLEARING DIAGNOSTIC TROUBLE CODES

1. After performing repairs, clear Engine Control Module (ECM) memory of all stored Diagnostic Trouble Codes (DTCs) and freeze frame data. DTCs and freeze frame data may be cleared by using scan tool and scan tool manufacturer's instructions. Using scan tool or Toyota hand-held tester, follow the manufacturer's instructions and clear DTCs and freeze frame data from ECM.
2. DTCs and freeze fame data may also be cleared by removing EFI fuse (20-amp). EFI fuse is located in fuse/relay box at driver's side front corner of engine compartment. DTCs and freeze frame data may also be cleared by disconnecting negative battery cable. However, other memory functions (clock, radio, alarm, seats, etc.) will be cleared and must be reset.

TEST DRIVE CONFIRMATION

1. On certain Diagnostic Trouble Codes (DTC), once DTC has been cleared from ECM memory, a DTC test drive confirmation test can be performed to verify repairs are made and that DTC does not reset. Test drive confirmation test will duplicate conditions required to set specified DTCs.
2. Test drive confirmation test lists the procedure to be performed to check that DTC does not reset. Test drive confirmation tests apply only to specific DTCs. Test drive confirmation test will be included within proper DTC test under DIAGNOSTIC TESTS.

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TESTS

Note. Before performing any diagnostic test, see SELF-DIAGNOSTIC SYSTEM for diagnostic system functions and system diagnostic procedures. Also check for any related Technical Service Bulletins (TSBs). For component location, see appropriate illustration in THEORY & OPERATION article. When performing diagnostic tests, it may be necessary to identify Engine Control Module (ECM) connector terminals which are referenced to in testing procedure. (Scheme 98)

Note. For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY & OPERATION article.

Scheme 98

Diagnosis & Repair

1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on and then turn hand-held tester or scan tool on. Start engine and allow engine to idle. Using hand-held tester or scan tool, monitor MAF meter air flow rate. If MAF meter air flow rate is 0.0 gm/sec., go to next step. If MAF meter air flow rate is 271 gm/sec. or more, go to step 5.
2. Turn ignition off. Disconnect MAF meter harness connector. Turn ignition on. Measure voltage between terminals No. 1 (Black/White wire) and No. 5 (White wire) at MAF meter harness connector. (Scheme 99) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, go to step 7.
3. Turn ignition off. Connect MAF meter harness connector. Access ECM behind glove box. see scheme 2 Ensure shift lever is in Neutral or Park. Ensure A/C switch is OFF. Start engine and let idle. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 12 (Yellow/Green wire) and No. 18 (White wire) at ECM harness connector E8. (Scheme 98) If voltage is not.5-3.0 volts, go to next step. If voltage is.5-3.0 volts, replace ECM.
4. Turn ignition off. Check for open or short in wiring between MAF meter and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace MAF meter.
5. Turn ignition off. Access ECM behind glove box. see scheme 2 Using DVOM, backprobe ECM harness connector and measure resistance between terminals No. 18 (White wire) and No. 21 (Red/Black wire) at ECM harness connector E8. (Scheme 98) If resistance is one ohm or less, go to next step. If resistance is greater than one ohm, replace ECM.
6. Check for open or short in wiring between MAF meter and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace MAF meter.
7. Turn ignition off. Disconnect negative battery cable. Access ECM behind glove box. see scheme 2 Disconnect ECM harness connectors E8. (Scheme 98) Remove EFI relay from engine room junction box. Engine room junction box is located on driver's side of engine compartment. Measure resistance in Black/White wire between terminal No. 1 at MAF meter harness connector and socket No. 3 of EFI relay in engine room junction box. (Scheme 99)and (Scheme 100). If resistance is one ohm or less, go to next step. If resistance is greater than one ohm, repair open in Black/White wire.
8. Measure resistance of White wire between terminal No. 5 at MAF meter harness connector and terminal No. 18 at ECM harness connector E8. If resistance is one ohm or less, check ECM power source circuit. If resistance is greater than one ohm, repair open in White wire.

Scheme 99

Scheme 100

Using Toyota hand-held tester or scan tool, check for any other DTCs. If other DTCs exist, diagnose and repair those DTCs first and retest. If only DTC P0101 exists, replace MAF meter.

1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on. Turn ignition on and then turn hand-held tester or scan tool on. Using hand-held tester or scan tool, read intake air temperature for IAT sensor. If displayed intake air temperature is -40°F (-40°C), go to next step. If displayed intake air temperature is 284°F (140°C) or more, go to step 4. If displayed intake air temperature is the same as actual air intake temperature, problem is intermittent. Check for defective connections or intermittent problem in wiring between MAF meter and ECM.
2. Turn ignition off. Disconnect MAF meter harness connector. Using a jumper wire, connect MAF meter harness connector terminals No. 4 (Red/Yellow wire) and No. 5 (White wire). (Scheme 99) Turn ignition on. Using hand-held tester or scan tool, read intake air temperature for IAT sensor. If displayed intake air temperature is less than 284°F (140°C), go to next step. If displayed intake air temperature is 284°F (140°C) or more, replace MAF meter.
3. Turn ignition off. Remove jumper wire. Access ECM behind glove box. see scheme 2 Using a jumper wire, backprobe between terminal No. 23 (Red/Yellow wire) at ECM harness connector E9 and No. 18 (White wire) at ECM harness connector E8. (Scheme 98) If displayed intake air temperature is 284°F (140°C) or more, repair open in Red/Yellow wire and/or White wire between MAF meter and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If displayed intake air temperature is less than 284°F (140°C), replace ECM.
4. Turn ignition off. Disconnect MAF meter harness connector. Turn ignition on. If displayed intake air temperature is not -40°F (-40°C), go to next step. If displayed intake air temperature is -40°F (-40°C), replace MAF meter.
5. Turn ignition off. Access ECM behind glove box. see scheme 2 Disconnect ECM harness connectors E8 and E9. (Scheme 98) Turn ignition on. If displayed intake air temperature is -40°F (-40°C), repair short in Red/Yellow wire between MAF meter and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If displayed intake air temperature is not -40°F (-40°C), replace ECM.

1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on and then turn hand-held tester or scan tool on. Using hand-held tester or scan tool, monitor ECT sensor temperature. If displayed temperature is same as actual coolant temperature, problem is intermittent. Check component and ECM connections. If displayed temperature is -40°F (-40°C), go to next step. If displayed temperature is 284°F (140°C) or more, go to step 4.
2. Turn ignition off. Disconnect ECT sensor harness connector (2-pin harness connector with White/Blue wire and White wire). ECT sensor is located on transaxle side of cylinder head. Using a jumper wire, connect ECT sensor harness connector terminals. Turn ignition on. Using hand-held tester or scan tool, monitor ECT sensor temperature. If displayed temperature is less than 284°F (140°C), go to next step. If displayed temperature is 284°F (140°C) or more, replace ECT sensor.
3. Turn ignition off. Remove jumper wire. Access ECM behind glove box. see scheme 2 Using a jumper wire, backprobe between terminals No. 22 (White/Blue wire) at ECM harness connector E9 and terminal No. 18 (White wire) at ECM harness connector E8. (Scheme 98) If displayed temperature is 284°F (140°C) or more, repair open in White/Blue wire and/or White wire between ECT sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If displayed temperature is less than 284°F (140°C), replace ECM.
4. Turn ignition off. Disconnect ECT sensor harness connector (2-pin harness connector with White/Blue wire and White wire). ECT sensor is located on transaxle side of cylinder head. Turn ignition on. If displayed temperature is not -40°F (-40°C), go to next step. If displayed temperature is -40°F (-40°C), replace ECT sensor.
5. Turn ignition off. Access ECM behind glove box. see scheme 2 Disconnect ECM harness connectors E8 and E9. (Scheme 98) Turn ignition on. If displayed temperature is -40°F (-40°C), repair short in White/Blue wire between ECT sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If displayed temperature is not -40°F (-40°C), replace ECM.

1. Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.
2. Remove and inspect cooling system thermostat. If problem exists, replace thermostat as necessary and retest. If problem does not exist, replace ECT sensor. ECT sensor is located on transaxle side of cylinder head and uses a 2-pin harness connector with White/Blue and White wires.

1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on and then turn hand-held tester or scan tool on. Using hand-held tester or scan tool, monitor throttle valve opening percentage. Opening percentage should be approximately 10 percent with fully closed throttle, and 75 percent with fully open throttle. If percentages are not as specified, go to next step. If percentages are as specified, problem may be intermittent. Check component and ECM connections.
2. Turn ignition off. Disconnect TP sensor harness connector. Turn ignition on. Measure voltage between terminals No. 1 (Blue/Red wire) and No. 2 (White wire) at TP sensor 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 5.
3. Turn ignition off. Check TP sensor. See «ENGINE SENSORS & SWITCHES»(ref-133221-S30584064082002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If TP sensor is okay, go to next step. If TP sensor is defective, replace TP sensor.
4. Connect TP sensor harness connector. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 24 (Black/White wire) at ECM harness connector E9 and terminal No. 18 (White wire) at ECM harness connector E8. (Scheme 98) Voltage should be.3-1.0 volt with throttle fully closed and 3.2-4.9 volts with throttle fully open. If voltages are as specified, replace ECM. If voltages are not as specified, repair open or short in Black/White wire between TP sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article.
5. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (White wire) at ECM harness connector E8. (Scheme 98) If voltage is 4.5-5.5 volts, repair open in Blue/Red wire between TP sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If voltage is not 4.5-5.5 volts, replace ECM.

Using Toyota hand-held tester or scan tool, check for any other DTCs. If other DTCs exist, diagnose and repair those DTCs first and retest. If only DTC P0121 exists, replace TP sensor.

1. Connect Toyota hand-held tester to Data Link Connector (DLC) No. 3. see scheme 1 Start engine and allow engine to idle for 100 seconds or more.
2. Drive vehicle at 24 MPH or more for 20 seconds or more. Let engine idle for 20 seconds or more. Repeat driving and idling portion of procedure 3 more times. Let engine idle for 30 seconds or more. Using hand-held tester, check A/F sensor voltage. If malfunction exists, MIL will illuminate.

1. Using Toyota hand-held tester or scan tool, check for any other DTCs. If only DTC P0125 exists, go to next step. If other DTCs exist, diagnose and repair those DTCs first and retest.
2. With Toyota hand-held tester or scan tool still connected to DLC No. 3, start engine and increase engine speed to 2500 RPM for approximately 90 seconds to fully warm the A/F sensor. Allow engine to idle. Using hand-held tester or scan tool, monitor each A/F sensor output voltage with engine idling, engine racing and while driving vehicle at 25 MPH or more with engine speed at 1500 RPM or more while opening and closing the throttle. Ensure A/F sensor output voltage is as specified. See «AIR/FUEL SENSOR VOLTAGE SPECIFICATIONS»(ref-133207-S35614802502002021900000) table. If voltage is as specified, go to next step. If voltage is not as specified, go to step 9. NOTE: If A/F sensor output voltage remains 3.30 volts (Toyota hand-held tester) or.66 volt (OBD-II scan tool) during all conditions, A/F sensor circuit may be open. If A/F sensor output voltage remains 3.80 volts or more (Toyota hand-held tester) or.76 volt or more (OBD-II scan tool) during all conditions, A/F sensor circuit may be shorted. If A/F sensor output voltage remains 2.80 volts or less (Toyota hand-held tester) or.56 volt or less (OBD-II scan tool) during all conditions, A/F sensor circuit may be shorted. During fuel enrichment, A/F sensor output voltage may be less than 2.8 volts (Toyota hand-held tester) or.56 volt (OBD-II scan tool) which is normal. During fuel cut, A/F sensor output voltage may be more than 3.8 volts (Toyota hand-held tester) or.76 volt (OBD-II scan tool) which is normal. AIR/FUEL SENSOR OUTPUT VOLTAGE SPECIFICATIONS Application & Operating Condition Specification Using OBD-II Scan Tool Engine Idling, Engine Racing & Driving Vehicle (1) (2) Using Toyota Hand-Held Tester Engine Idling, Engine Racing & Driving Vehicle (1) (3) (1) Drive vehicle at 25 MPH or more with engine speed of 1500 RPM or more while opening and closing the throttle. (2) Voltage should not remain at.56 volt or less,.66 volt, or.76 volt or more. (3) Voltage should not remain at 2.80 volts or less, 3.30 volts, or 3.80 volts or more.
3. Check for open or short in wiring between ECM and suspect A/F sensor. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
4. Disconnect suspect A/F sensor harness connector. Measure resistance between terminal B+ (Red/White wire) and HT (Black/Red wire on bank No. 1; Black wire on bank No. 2) at A/F sensor connector (component side). (Scheme 101) Resistance should be 1.8-3.4 ohms at 68°F (20°C) and 5.0-7.5 ohms at 932°F (500°C). If resistance is as specified, go to next step. If resistance is not as specified, replace appropriate A/F sensor.
5. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, go to next step.
6. Check fuel pressure. See «FUEL SYSTEMS»(ref-133196-S02740135242002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm 2 ) at idle, and should be 21 psi (1.5 kg/cm 2 ) or more for 5 minutes after engine has stopped. If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, repair as necessary.
7. Check operation of fuel injectors. See «FUEL SYSTEMS»(ref-133196-S02740135242002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be 4.2-5.0 Cu. In. (69-82 cc) every 15 seconds and difference in volume between each fuel injector should be less than.8 Cu. In. (13 cc). Fuel injectors should not leak more than one drop every 12 minutes. If problem does not exist, go to next step. If problem exists, repair as necessary.
8. Check exhaust system for leaks. If problem exists, repair as necessary. If problem does not exist, replace defective A/F sensor(s).
9. Clear DTCs. Perform test drive confirmation, then go to next step. See «TEST DRIVE CONFIRMATION»(ref-133207-S12349550492002021900000).
10. Recheck for DTCs. If DTC P0125 is not displayed again, go to next step. If DTC P0125 is displayed again, replace ECM.
11. Vehicle either ran out of fuel or problem is intermittent. Check component and ECM connections.

Scheme 101

1. Remove and inspect cooling system thermostat. If problem does not exist, go to next step. If problem exists, replace thermostat as necessary and retest.
2. Using Toyota hand-held tester or scan tool, check for any other DTCs. If other DTCs exist, diagnose and repair those DTCs first and retest. If only DTC P0128 exists, replace ECM.

1. Using Toyota hand-held tester or scan tool, check for any other DTCs. If only DTC P0136 exists, go to next step. If other DTCs exist, diagnose and repair those DTCs first and retest.
2. Check for open or short in wiring between ECM and heated oxygen sensor No. 2. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
3. With hand-held tester or scan tool still connected to DLC No. 3, start engine and warm engine to normal operating temperature. Monitor heated oxygen 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. If voltage is as specified, problem is intermittent. Check component and ECM connections. If voltage is not as specified, replace appropriate heated oxygen sensor No. 2.

1. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe appropriate ECM harness connector. For heated oxygen sensor bank No. 1 sensor No. 2, measure voltage between ground and terminal No. 9 (Red/Blue wire) at ECM harness connector E8. (Scheme 98) For heated oxygen sensor bank No. 2 sensor No. 2, measure voltage between ground and terminal No. 14 (Black wire) at ECM harness connector E7. Voltage should be 9-14 volts. If voltage is not as specified, go to next step. If voltage is as specified, replace ECM.
2. Turn ignition off. Disconnect appropriate heated oxygen sensor No. 2 harness connector. For heated oxygen sensor bank No. 1 sensor No. 2, measure resistance between terminals HT (Red/Blue wire) and B+ (Black/White wire) at heated oxygen sensor No. 2 connector (component side). (Scheme 102) For heated oxygen sensor bank No. 2 sensor No. 2, measure resistance between terminals HT (Black wire) and B+ (Black/White wire) at heated oxygen sensor No. 2 connector (component side). Resistance should be 11-16 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace heated oxygen sensor No. 2.
3. Repair wiring between ECM and heated oxygen sensor No. 2, or between heated oxygen sensor No. 2 and EFI relay. See «WIRING DIAGRAMS»(ref-133228) article.

Scheme 102

1. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, go to next step.
2. Check operation of fuel injectors. See «FUEL SYSTEMS»(ref-133196-S02740135242002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be 4.2-5.0 Cu. In. (69-82 cc) every 15 seconds and difference in volume between each fuel injector should be less than.8 Cu. In. (13 cc). Fuel injectors should not leak more than one drop every 12 minutes. If problem does not exist, go to next step. If problem exists, repair as necessary.
3. Check Mass Airflow (MAF) meter and Engine Coolant Temperature (ECT) sensor. MAF meter may also be referred to as airflow meter. See «ENGINE SENSORS & SWITCHES»(ref-133221-S30584064082002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem does not exist, go to next step. If problem exists, replace appropriate component.
4. Check ignition system by performing spark test. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If problem does not exist, go to next step. If problem exists, repair as necessary.
5. Check fuel pressure. See «FUEL SYSTEMS»(ref-133196-S02740135242002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm 2 ) at idle, and should be 21 psi (1.5 kg/cm 2 ) or more for 5 minutes after engine has stopped. If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, repair as necessary.
6. Check exhaust system for leaks. If problem does not exist, go to next step. If problem exists, repair as necessary.
7. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Start engine and increase engine speed to 2500 RPM for approximately 90 seconds to fully warm the A/F sensor. Allow engine to idle.
8. Using hand-held tester or scan tool, monitor each A/F sensor output voltage with engine idling, engine racing and while driving vehicle at 25 MPH or more with engine speed at 1500 RPM or more while opening and closing the throttle. Ensure A/F sensor output voltage is as specified. See «AIR/FUEL SENSOR OUTPUT VOLTAGE SPECIFICATIONS»(ref-133207-S13374061892002021900000) table. If A/F sensor output voltage is not within specification, go to next step. If A/F sensor output voltage is within specification, go to step 10. AIR/FUEL SENSOR OUTPUT VOLTAGE SPECIFICATIONS Application & Operating Condition Specification Using OBD-II Scan Tool Engine Idling, Engine Racing & Driving Vehicle (1) (2) Using Toyota Hand-Held Tester Engine Idling, Engine Racing & Driving Vehicle (1) (3) (1) Drive vehicle at 25 MPH or more with engine speed of 1500 RPM or more while opening and closing the throttle. (2) Voltage should not remain at.56 volt or less,.66 volt, or.76 volt or more. (3) Voltage should not remain at 2.80 volts or less, 3.30 volts, or 3.80 volts or more.
9. Check for open or short in wiring between ECM and A/F sensor(s). See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace appropriate A/F sensor.
10. Using Toyota hand-held tester or scan tool, clear DTCs from ECM. Perform test drive confirmation, then go to next step. See «TEST DRIVE CONFIRMATION»(ref-133207-S38462202252002021900000) under DTC P1130 OR DTC P1150: AIR/FUEL SENSOR CIRCUIT RANGE/PERFORMANCE.
11. Recheck for DTCs. If DTC P0171, DTC P0172, DTC P0174 and/or DTC P0175 are displayed again, go to next step. If DTCs P0171, DTC P0172, DTC P0174 and/or DTC P0175 are displayed again, replace ECM.
12. Vehicle either ran out of fuel or problem is intermittent. Check component and ECM connections.

1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Record any DTCs and freeze frame data. If using hand-held tester, switch hand-held tester to CHECK mode. 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 the data list on hand-held tester or scan tool.
2. Drive vehicle at specified engine speeds. See «DRIVING PATTERN»(ref-133207-S09393273592002021900000) table. If using scan tool, turn ignition off after symptom is simulated the first time, then repeat test drive again. If using hand-held tester or scan tool, 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 RPM (1) Minutes Idling 5 3/4 1000 4 2000 2 1/2 3000 1 1/2 (1) Minimum specification is given.

1. Check vacuum hoses for leaks, blockage and proper routing. See VACUUM DIAGRAMS article. Also, check wiring and connectors for damage or poor connections. If problem exists, repair as necessary and perform «TEST DRIVE CONFIRMATION»(ref-133207-S24942002782002021900000). If problem does not exist, go to next step.
2. Check ignition system by performing spark test on misfiring cylinder. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If problem does not exist, go to next step. If problem exists, repair as necessary.
3. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM connector and measure voltage between ground and fuel injector terminals at ECM connector E9. See «IDENTIFYING ECM FUEL INJECTOR DRIVER TERMINALS»(ref-133207-S21098957322002021900000) table. (Scheme 98) If voltage is not 9-14 volts at each terminal, go to next step. If voltage is 9-14 volts at each terminal, go to step 6. IDENTIFYING ECM FUEL INJECTOR DRIVER TERMINALS Fuel Injector No. (1) Terminal No. Wire Color 1 1 Red/Blue 2 2 Yellow 3 3 Black/White 4 4 Blue (1) Terminals are located in ECM harness connector E9. (Scheme 98)
4. Disconnect fuel injector harness connector at misfiring cylinder. Measure resistance between fuel injector terminals (component side). Resistance should be 13.4-14.2 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace fuel injector.
5. Check for open or short in wiring between ECM and fuel injector. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair as necessary. If problem does not exist, repair open or short fuel injector power source circuit. See «WIRING DIAGRAMS»(ref-133228) article.
6. Check fuel pressure. See «FUEL SYSTEMS»(ref-133196-S02740135242002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm 2 ) at idle, and should be 21 psi (1.5 kg/cm 2 ) or more for 5 minutes after engine has stopped. If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, repair as necessary.
7. Check operation of fuel injectors. See «FUEL SYSTEMS»(ref-133196-S02740135242002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be 4.2-5.0 Cu. In. (69-82 cc) every 15 seconds and difference in volume between each fuel injector should be less than.8 Cu. In. (13 cc). Fuel injectors should not leak more than one drop every 12 minutes. If problem does not exist, go to next step. If problem exists, repair as necessary.
8. Check Mass Airflow (MAF) meter and Engine Coolant Temperature (ECT) sensor. MAF meter may also be referred to as airflow meter. See «ENGINE SENSORS & SWITCHES»(ref-133221-S30584064082002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem does not exist, go to next step. If problem exists, replace appropriate component.
9. Check engine compression on misfiring cylinder. See «BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER»(ref-133196) article. Check valve clearance on misfiring cylinder. See «ON-VEHICLE ADJUSTMENTS - 4-CYLINDER»(ref-133193) article. Check valve timing. See appropriate article in ENGINES. Repair as necessary.

For diagnosis and repair procedure, see DTC P0300: RANDOM MISFIRE DETECTED .

1. Turn ignition off. Access ECM behind glove box. see scheme 2 Disconnect ECM harness connector E9. Measure resistance between ground and terminal No. 27 (White wire) at ECM harness connector E9. (Scheme 98) If resistance is less than one megohm, go to next step. If resistance is one megohm or more, go to step 3.
2. Disconnect knock sensor harness connector. Check continuity between knock sensor housing and knock sensor terminal (component side). If continuity does not exist, go to next step. If continuity exists, replace knock sensor.
3. Check for open or short in wiring between knock sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
4. Install known-good knock sensor. Clear DTCs. Test drive vehicle. Retrieve DTCs. If DTC P0325 returns, replace ECM. If DTC P0325 does not return, original knock sensor was defective.

1. Disconnect CKP sensor harness connector. Measure resistance between CKP sensor connector terminals (component side). Resistance should be 985-1600 ohms with sensor temperature of 14-122°F (-10-50°C) and 1265-1890 ohms with sensor temperature of 122-212°F (50-100°C). If resistance is as specified, go to next step. If resistance is not as specified, replace CKP sensor.
2. Check for open or short in wiring between ECM and CKP sensor. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
3. Remove and inspect CKP sensor. Also, inspect signal plate. If problem exists, replace CKP sensor and/or signal plate as necessary. If problem does not exist, replace ECM.

1. Disconnect CMP sensor harness connector. Measure resistance between CMP sensor connector terminals (component side). Resistance should be 835-1400 ohms with sensor temperature of 14-122°F (-10-50°C) and 1060-1645 ohms with sensor temperature of 122-212°F (50-100°C). If resistance is as specified, go to next step. If resistance is not as specified, replace CMP sensor.
2. Check for open or short in wiring between ECM and CMP sensor. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
3. Remove and inspect CMP sensor. Also, inspect signal plate. If problem exists, replace CMP sensor and/or signal plate as necessary. If problem does not exist, replace ECM.

1. Using Toyota hand-held tester or scan tool, check for any other DTCs. If only DTC P0420 and/or P0430 is displayed, go to next step. If other DTCs are displayed, diagnose and repair those DTCs first and retest system.
2. Check exhaust system for leaks. If problem does not exist, go to next step. If problem exists, repair as necessary.
3. Check A/F sensor circuits. See «DTC P1130 OR DTC P1150: AIR/FUEL SENSOR CIRCUIT RANGE/PERFORMANCE»(ref-133207-S06737382042002021900000) . If problem does not exist, go to next step. If problem exists, repair as necessary.
4. Check heated oxygen sensor No. 2 circuits. See «DTC P0136 OR DTC P0156: HEATED OXYGEN SENSOR NO. 2 CIRCUIT»(ref-133207-S11641809712002021900000) . If problem exists, repair as necessary. If problem does not exist, replace exhaust manifold/catalytic converter assembly.

Note. If DTC P0441, DTC P0446, DTC P0450 or DTC P0451 is output after DTC P0440 or DTC P0442, perform appropriate test first before performing this test.

1. Check for cracks and deformations in fuel tank, charcoal canister and fuel tank filler pipe. Check for disconnected hoses and tubes around fuel tank and charcoal canister. If problem does not exist, go to next step. If problem exists, repair as necessary.
2. Check fuel tank cap to ensure fuel tank cap is a Original Equipment Manufacturer (OEM) fuel tank cap. If fuel tank cap is an OEM fuel tank cap, go to next step. If fuel tank cap is not an OEM fuel tank cap, replace fuel tank cap with an OEM fuel tank cap.
3. Ensure fuel tank cap is properly installed and tightened. If fuel tank cap is properly installed and tightened, go to next step. If fuel tank cap is not properly installed or tightened, reinstall and tighten as necessary.
4. Check fuel tank cap for damage and damaged gasket. If fuel tank cap is not damaged and gasket is okay, go to next step. If fuel tank cap or gasket is damaged, replace fuel tank cap with an OEM fuel tank cap.
5. Remove fuel tank cap. Visually inspect fuel tank filler pipe for damage. If problem does not exist, go to next step. If problem exists, replace fuel tank filler pipe as necessary.
6. Check vacuum hoses between vapor pressure sensor and fuel tank, and between charcoal canister and pressure switching valve VSV. Check hoses for correct installation, looseness and damage. If problem does not exist, go to next step. If problem exists, repair vacuum hoses as necessary.
7. Check hose and tube between fuel tank and charcoal canister for correct installation and damage. If problem does not exist, go to next step. If problem exists, repair as necessary.
8. Check charcoal canister for damage. If problem does not exist, go to next step. If problem exists, repair or replace as necessary.
9. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (White wire) at ECM harness connector E8. (Scheme 98) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
10. Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 21 (Blue/Black wire) at ECM harness connector E6 and terminal No. 18 (White wire) at ECM harness connector E8. (Scheme 98) Remove fuel tank cap. Voltage should be 3.0-3.6 volts. If voltage is not as specified, go to next step. If voltage is as specified, go to step 12.
11. Check for an open or short in wiring between vapor pressure sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.
12. Check fuel tank and fuel tank overfill valve. If problem exists, repair or replace fuel tank or fuel tank overfill valve as necessary. If problem does not exist, no fault is indicated at this time. Probable cause of DTC to set was an incorrectly installed fuel tank cap.

1. Check for cracks and deformations in fuel tank, charcoal canister and fuel tank filler pipe. Check for disconnected hoses and tubes around fuel tank and charcoal canister. If problem does not exist, go to next step. If problem exists, repair as necessary.
2. Check fuel tank cap to ensure fuel tank cap is a Original Equipment Manufacturer (OEM) fuel tank cap. If fuel tank cap is an OEM fuel tank cap, go to next step. If fuel tank cap is not an OEM fuel tank cap, replace fuel tank cap with an OEM fuel tank cap.
3. Ensure fuel tank cap is properly installed and tightened. If fuel tank cap is properly installed and tightened, go to next step. If fuel tank cap is not properly installed or tightened, reinstall and tighten as necessary.
4. Check fuel tank cap for damage and damaged gasket. If fuel tank cap is not damaged and gasket is okay, go to next step. If fuel tank cap or gasket is damaged, replace fuel tank cap with an OEM fuel tank cap.
5. Remove fuel tank cap. Visually inspect fuel tank filler pipe for damage. If problem does not exist, go to next step. If problem exists, replace fuel tank filler pipe as necessary.
6. Check vacuum hoses between vapor pressure sensor and fuel tank, and between charcoal canister and pressure switching valve VSV. Check hoses for correct installation, looseness and damage. If problem does not exist, go to next step. If problem exists, repair vacuum hoses as necessary.
7. Check hose and tube between fuel tank and charcoal canister for correct installation and damage. If problem does not exist, go to next step. If problem exists, repair as necessary.
8. Check all EVAP system electrical component connections. If problem does not exist, go to next step. If problem exists, repair as necessary.
9. Check vacuum hoses between charcoal canister and fuel tank, and between fuel filler neck and fuel tank. If problem does not exist, go to next step. If problem exists, repair as necessary.
10. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (White wire) at ECM harness connector E8. (Scheme 98) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
11. Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 21 (Blue/Black wire) at ECM harness connector E6 and terminal No. 18 (White wire) at ECM harness connector E8. (Scheme 98) Remove fuel tank cap. Voltage should be 3.0-3.6 volts. If voltage is not as specified, go to next step. If voltage is as specified, go to step 13.
12. Check for an open or short in wiring between vapor pressure sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.
13. Disconnect EVAP VSV vacuum hoses. Turn ignition on. Access ECM behind glove box. see scheme 2 Connect a jumper wire by backprobing between ground and terminal No. 6 (Black/Red wire) at ECM harness connector E8. (Scheme 98) With jumper wire connected, air applied to EVAP VSV port "E" should flow from port "F". (Scheme 103) Remove jumper wire. With jumper wire removed, air applied to EVAP VSV port "E" should not flow from port "F". If EVAP VSV does not function as specified, go to next step. If EVAP VSV functions as specified, go to step 16.
14. Connect all disconnected components. Check EVAP VSV operation. See «FUEL EVAPORATIVE SYSTEM»(ref-133221-S27194855212002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If EVAP VSV is okay, go to next step. If EVAP VSV is not okay, replace EVAP VSV and charcoal canister. Also, clean vacuum hose between throttle body and EVAP VSV, and between EVAP VSV and charcoal canister.
15. Check for an open or short in wiring between EFI relay and EVAP VSV, and between EVAP VSV and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
16. Disconnect canister closed valve VSV vacuum hoses. Turn ignition on. Access ECM behind glove box. see scheme 2 Connect a jumper wire by backprobing between ground and terminal No. 2 (Pink wire) at ECM harness connector E7. (Scheme 98) With jumper wire connected, air applied to canister closed valve VSV port "E" should not flow from port "F". (Scheme 104) Remove jumper wire. With jumper wire removed, air applied to canister closed valve VSV port "E" should flow from port "F". If canister closed valve VSV does not function as specified, go to next step. If canister closed valve VSV functions as specified, go to step 19.
17. Connect all disconnected components. Check canister closed valve VSV. See «FUEL EVAPORATIVE SYSTEM»(ref-133221-S27194855212002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If canister closed valve VSV is okay, go to next step. If canister closed valve VSV is defective, replace canister closed valve VSV and charcoal canister. Also, clean vacuum hose between charcoal canister and canister closed valve VSV.
18. Check for an open or short in wiring between EFI relay and canister closed valve VSV, and between canister closed valve VSV and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
19. Disconnect pressure switching valve VSV vacuum hoses. Turn ignition on. Access ECM behind glove box. see scheme 2 Connect a jumper wire by backprobing between ground and terminal No. 6 (Green/Yellow wire) at ECM harness connector E6. (Scheme 98) With jumper wire connected, air applied to pressure switching valve VSV port "E" should flow from port "F". (Scheme 105) Remove jumper wire. With jumper wire removed, air applied to pressure switching valve VSV port "E" should not flow from port "F". If pressure switching valve VSV does not function as specified, go to next step. If pressure switching valve VSV functions as specified, go to step 22.
20. Connect all disconnected components. Check pressure switching valve VSV. See «FUEL EVAPORATIVE SYSTEM»(ref-133221-S27194855212002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If pressure switching valve VSV is okay, go to next step. If pressure switching valve VSV is defective, replace pressure switching valve VSV and charcoal canister. Also, clean vacuum hose between charcoal canister and pressure switching valve VSV, and between pressure switching valve VSV and fuel tank.
21. Check for an open or short in wiring between EFI relay and pressure switching valve VSV, and between pressure switching valve VSV and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
22. Charcoal canister or fuel tank overfill check valve maybe defective. Check fuel evaporative system. See «FUEL EVAPORATIVE SYSTEM»(ref-133221-S27194855212002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Repair as necessary.

Scheme 103

Scheme 104

Scheme 105

1. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 2 (Blue/Red wire) and No. 18 (White wire) at ECM harness connector E8. (Scheme 98) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
2. Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 21 (Blue/Black wire) at ECM harness connector E6 and terminal No. 18 (White wire) at ECM harness connector E8. (Scheme 98) Remove fuel tank cap. Voltage should be 3.0-3.6 volts. If voltage is not as specified, go to next step. If voltage is as specified, replace ECM.
3. Check for open or short in wiring between vapor pressure sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.

1. Test drive vehicle and check operation of speedometer. If speedometer is operating correctly, go to next step. If speedometer is not operating correctly, repair speedometer as necessary. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT.
2. Access ECM behind glove box. see scheme 2 Ensure ignition is off. Measure resistance between ground and terminal No. 22 (White/Red wire) at ECM harness connector E6. (Scheme 98) If resistance is more than one megohm, go to next step. If resistance is one megohm or less, locate and repair short to ground.
3. Turn ignition on. Raise and support vehicle. Measure voltage between ground and terminal No. 22 (White/Red wire) at ECM harness connector E6. Slowly rotate drive wheel. If voltage fluctuates between zero and 5 volts, replace ECM. If voltage does not fluctuate between zero and 5 volts, repair open in wiring between instrument cluster and ECM. See «WIRING DIAGRAMS»(ref-133228) article.

1. Start engine and warm to normal operating temperature. Turn all accessories off. Ensure A/C is off. Shift transaxle lever into Neutral. Note engine RPM. Using a jumper wire, connect terminals 13 (Pink/Black wire) and No. 4 (White/Black wire) at DLC No. 3 under dash. see scheme 3 Note engine RPM and compare RPM readings. If difference in engine speed is 100 RPM or less, go to next step. If difference in engine speed is more than 100 RPM, go to step 7.
2. Turn ignition off. Remove jumper wire. Disconnect IAC valve harness connector. Turn ignition on. Measure voltage between ground and terminal No. 2 (Black/White wire) at IAC valve harness connector. (Scheme 106) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, repair wiring between IAC valve and EFI relay. See «WIRING DIAGRAMS»(ref-133228) article.
3. Turn ignition off. Check continuity between ground and terminal No. 3 (Black/White wire) at IAC valve harness connector. If continuity exists, go to next step. If continuity does not exist, repair open in Black/White wire between IAC valve and ground. See «WIRING DIAGRAMS»(ref-133228) article.
4. Access ECM behind glove box. see scheme 2 Disconnect ECM harness connector E9. (Scheme 98) Check for open or short in Green/Black wire between terminal No. 1 at IAC valve harness connector and terminal No. 18 at ECM harness connector E9. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
5. Connect all disconnected components. Check IAC valve operation. See «IDLE CONTROL SYSTEMS»(ref-133221-S00550503572002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem does not exist, go to next step. If problem exists, replace IAC valve.
6. Remove IAC valve from throttle body. Check IAC valve and passages for carbon build-up and blockage. If problem exists, repair or replace as necessary. If problem does not exist, replace ECM.
7. Remove jumper wire. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, an open or short in A/C switch signal circuit may exist. Check A/C amplifier. See appropriate MANUAL «HIGHLANDER»(ref-138707) or AUTOMATIC «HIGHLANDER»(ref-138672) A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING. Repair as necessary.

Scheme 106

1. If using Toyota hand-held tester, go to next step. If Toyota hand-held tester is not available, go to step 4.
2. Connect hand-held tester to Data Link Connector (DLC) No. 3. see scheme 1 Switch hand-held tester from NORMAL mode to CHECK mode.
3. Start engine and warm engine to normal operating temperature with all accessories off. Drive vehicle at 38-75 MPH with engine speed at 1400-3200 RPM for 3-5 minutes. Stop vehicle and allow to idle for one minute. Check operation of Malfunction Indicator Light (MIL). If MIL illuminates, malfunction exists and DTC is set. If MIL does not illuminate, malfunction does not exist.
4. Start engine and warm engine to normal operating temperature. Drive vehicle at 38-75 MPH with engine speed at 1400-3200 RPM for 3-5 minutes. Stop vehicle and allow to idle for one minute. Turn ignition off. Repeat driving and idle part of test again and then check operation of Malfunction Indicator Light (MIL). If MIL illuminates, malfunction exists and DTC is set. If MIL does not illuminate, malfunction does not exist. If malfunction exists, MIL will illuminate.

1. Using Toyota hand-held tester or scan tool, check for any other DTCs. If only DTC P1130 or DTC P1150 exists, go to next step. If other DTCs exist, diagnose and repair those DTCs first and retest.
2. With Toyota hand-held tester or scan tool still connected to DLC No. 3, start engine and increase engine speed to 2500 RPM for approximately 90 seconds to fully warm the A/F sensor. Allow engine to idle.
3. Using hand-held tester or scan tool, monitor appropriate A/F sensor output voltage with engine idling, engine racing and while driving vehicle at 25 MPH or more with engine speed at 1500 RPM or more while opening and closing the throttle. Ensure A/F sensor output voltage is as specified. See «AIR/FUEL SENSOR OUTPUT VOLTAGE SPECIFICATIONS»(ref-133207-S34155190322002021900000) table. If A/F sensor output voltage is not as specified, go to next step. If A/F sensor output voltage is as specified, go to step 9. AIR/FUEL SENSOR OUTPUT VOLTAGE SPECIFICATIONS Application & Operating Condition Specification Using OBD-II Scan Tool Engine Idling, Engine Racing & Driving Vehicle (1) (2) Using Toyota Hand-Held Tester Engine Idling, Engine Racing & Driving Vehicle (1) (3) (1) Drive vehicle at 25 MPH or more with engine speed of 1500 RPM or more while opening and closing the throttle. (2) Voltage should not remain at.56 volt or less,.66 volt, or.76 volt or more. (3) Voltage should not remain at 2.80 volts or less, 3.30 volts, or 3.80 volts or more.
4. Check for open or short in wiring between ECM and suspect A/F sensor. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
5. Disconnect suspect A/F sensor harness connector. Measure resistance between terminal B+ (Red/White wire) and HT (Black/Red wire on bank No. 1; Black wire on bank No. 2) at A/F sensor connector (component side). (Scheme 101) Resistance should be 1.8-3.4 ohms at 68°F (20°C) and 5.0-7.5 ohms at 932°F (500°C). If resistance is as specified, go to next step. If resistance is not as specified, replace appropriate A/F sensor.
6. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem does not exist, go to next step. If problem exists, repair as necessary.
7. Check fuel pressure. See «FUEL SYSTEMS»(ref-133221-S24954902022002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm 2 ) at idle, and should be 21 psi (1.5 kg/cm 2 ) or more for 5 minutes after engine has stopped. If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, repair as necessary.
8. Check operation of fuel injectors. See «FUEL SYSTEMS»(ref-133221-S24954902022002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be 4.2-5.0 Cu. In. (69-82 cc) every 15 seconds and difference in volume between each fuel injector should be less than.8 Cu. In. (13 cc). Fuel injectors should not leak more than one drop every 12 minutes. If problem exists, repair as necessary. If problem does not exist, replace defective A/F sensor.
9. Using Toyota hand-held tester or scan tool, clear DTCs from ECM. Perform test drive confirmation, then go to next step. See «TEST DRIVE CONFIRMATION»(ref-133207-S38462202252002021900000).
10. Recheck for DTCs. If neither DTC P1130 nor DTC P1150 are displayed again, go to next step. If DTC P1130 and/or P1150 is displayed again, replace ECM.
11. Vehicle either ran out of fuel or problem is intermittent. Check component and ECM connections.

1. If using Toyota hand-held tester, go to next step. If Toyota hand-held tester is not available, go to step 4.
2. Connect hand-held tester to Data Link Connector (DLC) No. 3. see scheme 1 Switch hand-held tester to CHECK mode.
3. Start and warm engine to normal operating temperature with all accessories off. Drive vehicle at 38-75 MPH with engine speed at 1400-3200 RPM for 3-5 minutes. Stop vehicle and allow to idle for one minute. Check operation of Malfunction Indicator Light (MIL). If MIL illuminates, malfunction exists and DTC is set. If MIL does not illuminate, malfunction does not exist.
4. Start and warm engine to normal operating temperature. Drive vehicle at 38-75 MPH with engine speed at 1400-3200 RPM for 3-5 minutes. Stop vehicle and allow to idle for one minute. Turn ignition off. Repeat driving and idle part of test and then check operation of Malfunction Indicator Light (MIL). If MIL illuminates, malfunction exists and DTC is set. If MIL does not illuminate, malfunction does not exist. If malfunction exists, MIL will illuminate.

1. Using Toyota hand-held tester or scan tool, check for any other DTCs. If only DTC P1133 or DTC P1153 exists, go to next step. If other DTCs exist, diagnose and repair those DTCs first and retest.
2. With Toyota hand-held tester or scan tool still connected to DLC No. 3, start engine and maintain engine speed at 2500 RPM for about 90 seconds to fully warm the A/F sensor. Allow engine to idle.
3. Using hand-held tester or scan tool, monitor appropriate A/F sensor output voltage with engine idling, engine racing and while driving vehicle at 25 MPH or more with engine speed of 1500 RPM or more while opening and closing the throttle. Ensure A/F sensor output voltage is as specified. See «AIR/FUEL SENSOR OUTPUT VOLTAGE SPECIFICATIONS»(ref-133207-S30710085372002021900000) table. If A/F sensor output voltage is not as specified, go to next step. If voltage is not as specified, go to step 9. AIR/FUEL SENSOR OUTPUT VOLTAGE SPECIFICATIONS Application & Operating Condition Specification Using OBD-II Scan Tool Engine Idling, Engine Racing & Driving Vehicle (1) (2) Using Toyota Hand-Held Tester Engine Idling, Engine Racing & Driving Vehicle (1) (3) (1) Drive vehicle at 25 MPH or more with engine speed of 1500 RPM or more while opening and closing the throttle. (2) Voltage should not remain at.56 volt or less,.66 volt, or.76 volt or more. (3) Voltage should not remain at 2.80 volts or less, 3.30 volts, or 3.80 volts or more.
4. Check for open or short in wiring between ECM and suspect A/F sensor. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
5. Disconnect suspect A/F sensor harness connector. Measure resistance between terminal B+ (Red/White wire) and HT (Black/Red wire on bank No. 1; Black wire on bank No. 2) at A/F sensor connector (component side). (Scheme 101) Resistance should be 1.8-3.4 ohms at 68°F (20°C) and 5.0-7.5 ohms at 932°F (500°C). If resistance is as specified, go to next step. If resistance is not as specified, replace appropriate A/F sensor.
6. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem does not exist, go to next step. If problem exists, repair as necessary.
7. Check fuel pressure. See «FUEL SYSTEMS»(ref-133221-S24954902022002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm 2 ) at idle, and should be 21 psi (1.5 kg/cm 2 ) or more for 5 minutes after engine has stopped. If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, repair as necessary.
8. Check operation of fuel injectors. See «FUEL SYSTEMS»(ref-133221-S24954902022002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be 4.2-5.0 Cu. In. (69-82 cc) every 15 seconds and difference in volume between each fuel injector should be less than.8 Cu. In. (13 cc). Fuel injectors should not leak more than one drop every 12 minutes. If problem exists, repair as necessary. If problem does not exist, replace defective A/F sensor.
9. Using Toyota hand-held tester or scan tool, clear DTCs from ECM. Perform test drive confirmation, then go to next step. See «TEST DRIVE CONFIRMATION»(ref-133207-S03416621282002021900000).
10. Recheck for DTCs. If neither DTC P1133 or P1153 is displayed again, go to next step. If DTC P1133 and/or P1153 is displayed again, replace ECM.
11. Vehicle either ran out of fuel or problem is intermittent. Check component and ECM connections.

1. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe at ECM harness connector E8 and measure voltage between ground and terminals No. 4 (Black/Red wire) and No. 5 (Black wire). (Scheme 98) If either voltage is not 9-14 volts, go to next step. If both voltages are 9-14 volts, replace ECM.
2. Disconnect suspect A/F sensor harness connector. Measure resistance between terminal B+ (Red/White wire) and HT (Black/Red wire on bank No. 1; Black wire on bank No. 2) at A/F sensor connector (component side). (Scheme 101) Resistance should be 1.8-3.4 ohms at 68°F (20°C) and 5.0-7.5 ohms at 932°F (500°C). If resistance is as specified, go to next step. If resistance is not as specified, replace appropriate A/F sensor.
3. Check A/F heater relay. A/F heater relay may also be referred to as A/F sensor relay or A/F relay. See «A/F HEATER RELAY»(ref-133221-S17588861092002021900000) under MODULES, MOTORS, RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If A/F heater relay is defective, replace A/F heater relay. If A/F heater relay is okay, repair open or short in wiring between A/F heater relay and A/F sensor, and/or between A/F sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article.

1. Check for spark at cylinder No. 1 by performing spark test. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Cylinder No. 1 is the front cylinder at timing chain end of engine. If spark is exists, go to next step. If spark does not exist, go to step 4.
2. Check for open or short in White wire between terminal No. 25 at ECM harness connector E9 and terminal No. 2 at ignitor/ignition coil No. 1 harness connector. (Scheme 98)and (Scheme 107). If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
3. Disconnect ignitor/ignition coil No. 1 harness connector. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM and measure voltage between ground and terminal No. 25 (White wire) at harness connector E9. (Scheme 98) If voltage is 4.5-5.5 volts, replace ignitor/ignition coil No. 1. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in Black/Yellow wire between terminal No. 10 at ECM harness connector E9 and terminal No. 3 at ignitor/ignition coil No. 1 harness connector. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
5. Access ECM behind glove box. see scheme 2 Using DVOM, backprobe ECM and measure voltage between ground and terminal No. 10 (Black/Yellow wire) at ECM harness connector E9 while cranking engine. (Scheme 98) If.1-4.5 volts does not exist, go to next step. If.1-4.5 volts exists, go to step 7.
6. Turn ignition off. Disconnect ignitor/ignition coil No. 1 harness connector. Using DVOM, backprobe ECM and measure voltage between ground and terminal No. 10 (Black/Yellow wire) at ECM harness connector E9 while cranking engine. If.1-4.5 volts exists, replace ignitor/ignition coil No. 1. If.1-4.5 volts does not exist, replace ECM.
7. Turn ignition off. Disconnect ignitor/ignition coil No. 1 harness connector. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black wire) at ignitor/ignition coil No. 1 harness connector. (Scheme 107) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignitor/ignition coil No. 1 power source circuit. See «WIRING DIAGRAMS»(ref-133228) article.
8. Check ignitor/ignition coil No. 1 ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair as necessary. If problem does not exist, replace ignitor/ignition coil No. 1.

Scheme 107

1. Check for spark at cylinder No. 2 by performing spark test. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Cylinder No. 2 is second cylinder from timing chain end of engine. If spark is exists, go to next step. If spark does not exist, go to step 4.
2. Check for open or short in White wire between terminal No. 25 at ECM harness connector E9 and terminal No. 2 at ignitor/ignition coil No. 2 harness connector. (Scheme 98)and (Scheme 107). If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
3. Disconnect ignitor/ignition coil No. 2 harness connector. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM and measure voltage between ground and terminal No. 25 (White wire) at ECM harness connector E9. (Scheme 98) If voltage is 4.5-5.5 volts, replace ignitor/ignition coil No. 2. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in Yellow/Green wire between terminal No. 11 at ECM harness connector E9 and terminal No. 3 at ignitor/ignition coil No. 2 harness connector. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
5. Access ECM behind glove box. see scheme 2 Using DVOM, backprobe ECM and measure voltage between ground and terminal No. 11 (Yellow/Green wire) at ECM harness connector E9 while cranking engine. (Scheme 98) If.1-4.5 volts does not exist, go to next step. If.1-4.5 volts exists, go to step 7.
6. Turn ignition off. Disconnect ignitor/ignition coil No. 2 harness connector. Using DVOM, backprobe ECM and measure voltage between ground and terminal No. 11 (Yellow/Green wire) at ECM harness connector E9 while cranking engine. If.1-4.5 volts exists, replace ignitor/ignition coil No. 2. If.1-4.5 volts does not exist, replace ECM.
7. Turn ignition off. Disconnect ignitor/ignition coil No. 2 harness connector. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black wire) at ignitor/ignition coil No. 2 harness connector. (Scheme 107) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignitor/ignition coil No. 2 power source circuit. See «WIRING DIAGRAMS»(ref-133228) article.
8. Check ignitor/ignition coil No. 2 ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair as necessary. If problem does not exist, replace ignitor/ignition coil No. 2.

1. Check for spark at cylinder No. 3 by performing spark test. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Cylinder No. 3 is third cylinder from timing chain end of engine. If spark is exists, go to next step. If spark does not exist, go to step 4.
2. Check for open or short in White wire between terminal No. 25 at ECM harness connector E9 and terminal No. 2 at ignitor/ignition coil No. 3 harness connector. (Scheme 98)and (Scheme 107). If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
3. Disconnect ignitor/ignition coil No. 3 harness connector. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM and measure voltage between ground and terminal No. 25 (White wire) at ECM harness connector E9. (Scheme 98) If voltage is 4.5-5.5 volts, replace ignitor/ignition coil No. 3. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in Blue/Yellow wire between terminal No. 12 at ECM harness connector E9 and terminal No. 3 at ignitor/ignition coil No. 3 harness connector. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
5. Access ECM behind glove box. see scheme 2 Using DVOM, backprobe ECM and measure voltage between ground and terminal No. 12 (Blue/Yellow wire) at ECM harness connector E9 while cranking engine. (Scheme 98) If.1-4.5 volts does not exist, go to next step. If.1-4.5 volts exists, go to step 7.
6. Turn ignition off. Disconnect ignitor/ignition coil No. 3 harness connector. Using DVOM, backprobe ECM and measure voltage between ground and terminal No. 12 (Blue/Yellow wire) at ECM harness connector E9 while cranking engine. If.1-4.5 volts exists, replace ignitor/ignition coil No. 3. If.1-4.5 volts does not exist, replace ECM.
7. Turn ignition off. Disconnect ignitor/ignition coil No. 3 harness connector. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black wire) at ignitor/ignition coil No. 3 harness connector. (Scheme 107) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignitor/ignition coil No. 3 power source circuit. See «WIRING DIAGRAMS»(ref-133228) article.
8. Check ignitor/ignition coil No. 3 ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair as necessary. If problem does not exist, replace ignitor/ignition coil No. 3.

1. Check for spark at cylinder No. 4 by performing spark test. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Cylinder No. 4 is fourth cylinder from timing chain end of engine. If spark is exists, go to next step. If spark does not exist, go to step 4.
2. Check for open or short in White wire between terminal No. 25 at ECM harness connector E9 and terminal No. 2 at ignitor/ignition coil No. 4 harness connector. (Scheme 98)and (Scheme 107). If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
3. Disconnect ignitor/ignition coil No. 4 harness connector. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM and measure voltage between ground and terminal No. 25 (White wire) at ECM harness connector E9. (Scheme 98) If voltage is 4.5-5.5 volts, replace ignitor/ignition coil No. 4. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in Blue/Red wire between terminal No. 13 at ECM harness connector E9 and terminal No. 3 at ignitor/ignition coil No. 4 harness connector. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
5. Access ECM behind glove box. see scheme 2 Using DVOM, backprobe ECM and measure voltage between ground and terminal No. 13 (Blue/Red wire) at ECM harness connector E9 while cranking engine. (Scheme 98) If.1-4.5 volts does not exist, go to next step. If.1-4.5 volts exists, go to step 7.
6. Turn ignition off. Disconnect ignitor/ignition coil No. 4 harness connector. Using DVOM, backprobe ECM and measure voltage between ground and terminal No. 13 (Blue/Red wire) at ECM harness connector E9 while cranking engine. If.1-4.5 volts exists, replace ignitor/ignition coil No. 4. If.1-4.5 volts does not exist, replace ECM.
7. Turn ignition off. Disconnect ignitor/ignition coil No. 4 harness connector. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black wire) at ignitor/ignition coil No. 4 harness connector. (Scheme 107) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignitor/ignition coil No. 4 power source circuit. See «WIRING DIAGRAMS»(ref-133228) article.
8. Check ignitor/ignition coil No. 4 ground circuit. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair as necessary. If problem does not exist, replace ignitor/ignition coil No. 4.

Check valve timing. Check for loose, stretched or jumped teeth of timing chain. See appropriate article in ENGINES. If problem exists, repair as necessary. If problem does not exist, replace ECM.

Diagnosis & Repair (Using Toyota Hand-Held Tester)

1. Check valve timing. See appropriate article in ENGINES. If problem exists, repair as necessary. If problem does not exist, go to next step.
2. Start engine and warm to normal operating temperature. Connect hand-held tester to Data Link Connector (DLC) No. 3. see scheme 1 Using hand-held tester, select ACTIVE TEST mode. Select VVT. Note idle speed when VVT OCV is activated by hand-held tester. Idle speed should be normal with VVT OCV off, and engine should idle rough or stalls when VVT OCV is on. If idle speed does not function as specified, go to next step. If idle speed functions as specified, VVT is functioning properly at this time. DTC may have been set because of a foreign object that was temporarily caught in the engine oil system but after a short time system returned to normal.
3. Turn ignition off. Access ECM behind glove box. see scheme 2 Using oscilloscope, backprobe ECM harness connector and connect oscilloscope between terminals No. 19 (Green/White wire) and No. 29 (Yellow/Red wire) at ECM harness connector E9. (Scheme 98) Start engine and let idle. Ensure oscilloscope pattern is as shown in illustration. (Scheme 108) As engine speed is increased, waveform frequency ("A") should lengthen. If waveform pattern is as shown, go to next step. If waveform pattern is not as shown, replace ECM.
4. Turn ignition off. Check VVT controller assembly for proper operation. See appropriate article in ENGINES. If problem does not exist, go to next step. If problem exists, replace VVT controller assembly and go to next step.
5. Disconnect VVT OCV harness connector. Measure resistance between VVT OCV terminals (component side). Resistance should be 6.9-7.9 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace VVT OCV.
6. Remove VVT OCV. Connect a fused jumper wire between positive battery terminal and terminal No. 1 at VVT OCV. (Scheme 109) Connect another jumper wire between negative battery terminal and terminal No. 2 at VVT OCV and note VVT OCV plunger operation. With battery voltage applied, plunger on end of VVT OCV should extend. Disconnect a jumper wire. Without battery voltage applied, plunger should retract. If VVT OCV does not operate as specified, replace VVT OCV and go to next step. If VVT OCV operates as specified, go to next step.
7. Check blockage in VVT OCV. Check oil check valve and oil pipe located under VVT OCV. If problem does not exist, go to next step. If problem exists, repair as necessary.
8. Install all remove components and connect all disconnected harness connectors. Using hand-held tester, clear DTCs. Start engine and allow it to idle. Turn ignition off. Turn ignition on and check for DTCs. If DTC P1349 is not present, no problem is indicated at this time. DTC may have been set because of a foreign object that was temporarily caught in the engine oil system but after a short time system returned to normal. If DTC P1349 is present, replace ECM.

Scheme 108

Scheme 109

Diagnosis & Repair (Without Toyota Hand-Held Tester)

1. Check valve timing. See appropriate article in ENGINES. If problem exists, repair as necessary. If problem does not exist, go to next step.
2. Start engine and allow it to idle. Disconnect Variable Valve Timing (VVT) Oil Control Valve (OCV) and note idle speed. VVT OCV is located on front cylinder head, next to intake manifold. Engine idle speed should not change. Using jumper wires, apply battery voltage and ground to VVT OCV terminals (component side). Engine should idle rough or stall. If VVT OCV operates as specified, go to next step. If VVT OCV does not operate as specified, go to step 4.
3. Turn ignition off. Connect VVT OCV harness connector. Access ECM behind glove box. see scheme 2 Using oscilloscope, backprobe ECM harness connector and connect oscilloscope between terminals No. 19 (Green/White wire) and No. 29 (Yellow/red wire) at ECM harness connector E9. (Scheme 98) Start engine and let idle. Ensure oscilloscope pattern is as shown in illustration. (Scheme 108) As engine speed is increased, waveform frequency ("A") should lengthen. If waveform pattern is as shown, no problem is indicated at this time. DTC may have been set because of a foreign object that was temporarily caught in the engine oil system but after a short time system returned to normal. If waveform pattern is not as shown, replace ECM.
4. Turn ignition off. Check VVT controller assembly for proper operation. See appropriate article in ENGINES. If problem does not exist, go to next step. If problem exists, replace VVT controller assembly and go to next step.
5. Disconnect VVT OCV harness connector. Measure resistance between VVT OCV terminals (component side). Resistance should be 6.9-7.9 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace VVT OCV.
6. Remove VVT OCV. Connect a fused jumper wire between positive battery terminal and terminal No. 1 at VVT OCV. (Scheme 109) Connect another jumper wire between negative battery terminal and terminal No. 2 at VVT OCV and note VVT OCV plunger operation. With battery voltage applied, plunger on end of VVT OCV should extend. Disconnect a jumper wire. Without battery voltage applied, plunger should retract. If VVT OCV operates as specified, go to next step. If VVT OCV does not operate as specified, replace VVT OCV and go to next step.
7. Check blockage in VVT OCV. Check oil check valve and oil pipe located under VVT OCV. If problem does not exist, go to next step. If problem exists, repair as necessary.
8. Install remove components all and connect all disconnected harness connectors. Using scan tool, clear DTCs. Start engine and allow it to idle. Turn ignition off. Turn ignition on and check for DTCs. If DTC P1349 is not present, no problem is indicated at this time. DTC may have been set because of a foreign object that was temporarily caught in the engine oil system but after a short time system returned to normal. If DTC P1349 is present, replace ECM.

1. Check stoplight operation. If stoplights do not operate properly, repair as necessary and retest system. See EXTERIOR LIGHTS article in ACCESSORIES & EQUIPMENT. If stoplights operate properly, go to next step.
2. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 15 (Green/White wire) at ECM harness connector E5. (Scheme 98) Voltage should be 7.5-14.0 volts with brake pedal depressed, and less than 1.5 volts with brake pedal released. If voltage is not as specified, go to next step. If voltage is as specified, problem is intermittent. Check component and ECM connections.
3. Check for open or short in wiring between ECM and stoplight switch. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.

1. Turn ignition off. Access ECM behind glove box. see scheme 2 Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 1 (Black/White wire) at ECM harness connector E5. (Scheme 98) If voltage is not 9-14 volts, go to next step. If voltage is 9-14 volts, replace ECM.
2. Remove EFI fuse (20-amp) from engine compartment fuse box. Inspect EFI fuse. If EFI fuse is okay, reinstall fuse. Check wiring harness and electrical connectors between EFI fuse and ECM. See «WIRING DIAGRAMS»(ref-133228) article. It may be necessary to check wiring between battery and EFI fuse. For additional wiring for EFI fuse to the battery, see POWER DISTRIBUTION article in «WIRING DIAGRAMS»(ref-133228). If EFI fuse is defective, replace fuse and check for short in wiring harness and components connected to EFI fuse. See «WIRING DIAGRAMS»(ref-133228) article. Repair wiring harness or electrical connectors as necessary.

1. Turn ignition off. Access ECM and body ECU behind glove box. see scheme 2 Disconnect ECM harness connector E5. (Scheme 98) Disconnect body ECU harness connector B10. (Scheme 110) Disconnect instrument cluster harness connector C12. (Scheme 111) Check continuity in Yellow wire between terminal No. 12 at ECM harness connector E5 and terminal No. 6 at body ECU harness connector B10. Check continuity in Blue/White wire between terminal No. 19 at ECM harness connector E5 and terminal No. 9 at instrument cluster harness connector C12. If continuity exists in both wires, go to next step. If continuity does not exist in either wire, repair wiring as necessary.
2. Connect all disconnected components. Turn ignition on. Using a DVOM, backprobe ECM harness connector and measure voltage between ground and terminals No. 1 (Black/White wire) and No. 16 (White wire) at ECM harness connector E5. If battery voltage exists at both terminals, go to next step. If battery voltage does not exist at either terminal, repair power distribution circuit(s) as necessary. See «WIRING DIAGRAMS»(ref-133228) article.
3. Turn ignition off. Using a DVOM, backprobe ECM harness connector and check continuity between ground and terminal No. 17 (Brown wire) at ECM harness connector E8. If continuity exists, replace ECM. If continuity does not exist, repair wiring as necessary. See «WIRING DIAGRAMS»(ref-133228) article.

Scheme 110

Scheme 111

1. Connect hand-held tester to Data Link Connector (DLC) No. 3. see scheme 1 Using hand-held tester, select ACTIVE TEST mode. Select VVT. Note idle speed when Variable Valve Timing (VVT) Oil Control Valve (OCV) is activated by hand-held tester. If idle speed does not function as specified, go to next step. If idle speed is normal with VVT OCV off, and engine idles rough or stalls when VVT OCV is on, VVT is functioning properly at this time. DTC may have been set because of a foreign object that was temporarily caught in engine oil system but after a short time system returned to normal.
2. Start engine and allow it to idle. Disconnect VVT OCV harness connector and note idle speed. OCV is located in cylinder head, at timing chain side of engine. Engine idle speed should not change. Using jumper wires, apply battery voltage and ground to VVT OCV terminals. Engine should idle rough or stall. If VVT OCV operates as specified, go to next step. If VVT OCV does not operate as specified, replace VVT OCV.
3. Turn ignition off. Connect VVT OCV harness connector. Access ECM behind glove box. see scheme 2 Using oscilloscope, backprobe ECM harness connector and connect oscilloscope between terminals No. 19 (Green/White wire) and No. 29 (Yellow/red wire) at ECM harness connector E9. (Scheme 98) Start engine and let idle. Ensure oscilloscope pattern is as shown in illustration. (Scheme 108) As engine speed is increased, waveform frequency ("A") should lengthen. If waveform pattern is as shown, go to next step. If waveform pattern is not as shown, replace ECM.
4. Check for an open or short in wiring between VVT OCV and ECM. If problem exists, repair wiring as necessary. If problem does not exist, problem is intermittent. Check component and ECM connections.

1. Start engine and allow it to idle. Disconnect Variable Valve Timing (VVT) Oil Control Valve (OCV) harness connector and note idle speed. OCV is located in cylinder head, at timing chain side of engine. VVT OCV is located on timing chain side of cylinder head. Engine idle speed should not change. Using jumper wires, apply battery voltage and ground to VVT OCV. Engine should idle rough or stall. If VVT OCV operates as specified, go to next step. If VVT OCV does not operate as specified, replace VVT OCV.
2. Turn ignition off. Connect VVT OCV harness connector. Access ECM behind glove box. see scheme 2 Using oscilloscope, backprobe ECM harness connector and connect oscilloscope between terminals No. 19 (Green/White wire) and No. 29 (Yellow/red wire) at ECM harness connector E9. (Scheme 98) Start engine and let idle. Ensure oscilloscope pattern is as shown in illustration. (Scheme 108) As engine speed is increased, waveform frequency ("A") should lengthen. If waveform pattern is as shown, go to next step. If waveform pattern is not as shown, replace ECM.
3. Check for an open or short in wiring between VVT OCV and ECM. If problem exists, repair wiring as necessary. If problem does not exist, problem is intermittent. Check component and ECM connections.

Note. Toyota hand-held tester can be used to confirm PNP switch signal from CURRENT DATA.

1. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Using scan tool, monitor gear position while shifting transmission through all gears. If scan tool display agrees with gear position, replace ECM. If scan tool display does not agree with gear position, go to next step.
2. Disconnect PNP switch harness connector. Check continuity between appropriate PNP switch terminals (component side) with shift lever in appropriate position. See «PARK/NEUTRAL POSITION SWITCH CONTINUITY»(ref-133207-S14880542132002021900000) table. (Scheme 112) If problem exists, replace PNP switch. If problem does not exist, go to next step. PARK/NEUTRAL POSITION SWITCH CONTINUITY Shift Lever Position Continuity Between Terminals No. Park 1 & 3; 6 & 9 Reverse 2 & 3 Neutral 3 & 5; 6 & 9 Drive 3 & 7 2 3 & 4 Low 3 & 8
3. Check wiring between battery and PNP switch and between PNP switch and ECM. See «WIRING DIAGRAMS»(ref-133228) article. It may be necessary to consult wiring diagram in appropriate STARTERS article in STARTING & CHARGING SYSTEMS for additional PNP switch wiring. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.

Scheme 112