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

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 located near the fuel gauge on instrument cluster on instrument panel. If MIL comes on and remains on, go to next step. If MIL does not come on, check bulb circuit on instrument cluster and Violet/Red wire and electrical connectors between MIL and Engine Control Module (ECM). See «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind glove box. see scheme 2
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-133217-S18352331732002021900000).

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-133217-S37564468592002021900000) .
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-133217-S01345015872002021900000) .
4. Visual Inspection Inspect all electrical connectors and wiring for suspected circuit or component. Ensure all 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-133217-S37564468592002021900000) .
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-133217-S20456746922002021900000) 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-133217-S01345015872002021900000) . 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 during CHECK mode, 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 at driver's side of instrument panel. 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, check DLC No. 3. See «DATA LINK CONNECTOR NO. 3 INSPECTION»(ref-133217-S02240353812002021900000) under SCAN TOOL PROBLEMS.
3. Record any DTCs and freeze frame data displayed for system diagnosis. If driveability problem exists and no DTCs are present, go to «TROUBLE SHOOTING - NO CODES»(ref-133220) article for diagnosis by symptom.
4. If any DTCs exist, perform appropriate DTC test under «DIAGNOSTIC TESTS»(ref-133217-S36694923332002021900000). For DTC descriptions, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-133217-S20456746922002021900000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. For information on freeze frame data, see «FREEZE FRAME DATA»(ref-133217-S27338874872002021900000). For information on two-trip detection logic codes, see «TWO-TRIP DETECTION LOGIC»(ref-133217-S19640687752002021900000).
5. After repairs for DTC have been completed, DTC must be cleared from Engine Control Module (ECM). See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-133217-S01345015872002021900000). 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 Engine Control Module (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. Place transmission in Park or Neutral. Ensure A/C and ignition are off. Check that throttle valve is fully closed. Connect hand-held tester to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. 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 exists and no DTCs are present, go to «TROUBLE SHOOTING - NO CODES»(ref-133220) article for diagnosis by symptom.
4. If any DTCs exist, perform appropriate DTC test under «DIAGNOSTIC TESTS»(ref-133217-S36694923332002021900000). For DTC descriptions, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-133217-S20456746922002021900000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. For information on freeze frame data, see «FREEZE FRAME DATA»(ref-133217-S27338874872002021900000). For information on two-trip detection logic DTCs, see «TWO-TRIP DETECTION LOGIC»(ref-133217-S19640687752002021900000).
5. After repairs for DTC have been completed, DTC must be cleared from Engine Control Module (ECM). See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-133217-S01345015872002021900000). Road test vehicle to ensure all symptoms and/or complaints have been repaired.

CLEARING DIAGNOSTIC TROUBLE CODES

1. After repairs for Diagnostic Trouble Codes (DTC) have been completed, DTCs and freeze frame data should be cleared from Engine Control Module (ECM) memory. 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 frame 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 various memory functions such as the 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 Engine Control Module (ECM) memory, test drive confirmation can be performed to verify repairs are made and that DTC does not reset. Test drive confirmation will duplicate conditions required to set specified DTCs.
2. Test drive confirmation lists the procedure to be performed to check that DTC does not reset. Test drive confirmation applies only to specific DTCs. Test drive confirmation will be included within proper DTC test under DIAGNOSTIC TESTS.

Scheme 98

1. If Toyota hand-held tester or scan tool displays UNABLE TO CONNECT TO VEHICLE when hand-held tester or scan tool is connected to Data Link Connector (DLC) No. 3, try hand-held tester or scan tool on another vehicle. If hand-held tester or scan tool operates on another vehicle, go to next step. If hand-held tester or scan tool does not operate on another vehicle, problem is probably with hand-held tester or scan tool.
2. Check voltage and resistance between ground and specified terminal on DLC No. 3. See «DATA LINK CONNECTOR NO. 3 VOLTAGE & RESISTANCE SPECIFICATIONS»(ref-133217-S18842647692002021900000) table. (Scheme 98) If voltage or resistance readings are not within specification, check wiring circuit. See «WIRING DIAGRAMS»(ref-133228) article. For full wiring diagram of DLC No. 3, it may be necessary to see DATA LINK CONNECTORS article in WIRING DIAGRAMS. DATA LINK CONNECTOR NO. 3 VOLTAGE & RESISTANCE SPECIFICATIONS Terminal No. (Circuit) Specification 4 (Chassis Ground) 1 Ohm Or Less 5 (Signal Ground) 1 Ohm Or Less 7 (BUS Communication) (1) 16 (Battery Voltage) 9-14 Volts (1) Pulse generation should exist during information transmission from Engine Control Module (ECM).

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TESTS

Note. Before performing any diagnostic test, refer to SELF-DIAGNOSTIC SYSTEM for diagnostic system functions and system diagnostic procedures. Also check for any related Technical Service Bulletins (TSBs).

Note. When performing diagnostic tests, it may be necessary to identify Engine Control Module (ECM) electrical connector terminals which are referenced to in testing procedure. (Scheme 99)

Scheme 99

Diagnosis & Repair

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. MAF meter is bolted to upper cap on air cleaner assembly and contains a Black 5-pin electrical connector. See AIRFLOW METER under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. see scheme 1 Turn ignition on and then turn hand-held tester or scan tool on.
2. Using hand-held tester or scan tool, read engine coolant temperature for ECT sensor. If displayed engine coolant temperature is -40°F (-40°C), go to next step. If displayed engine coolant temperature is 284°F (140°C) or more, go to step 8. If displayed engine coolant temperature is same as actual engine coolant temperature, problem is intermittent. Check for defective connections or intermittent problem in wiring between ECT sensor and ECM. ECT sensor is located on coolant housing at rear of cylinder head and contains Dark Gray 2-pin electrical connector with Green/Red and Blue/Black wires. ECM is located behind glove box. see scheme 2
3. Turn ignition off. Disconnect electrical connector at ECT sensor. ECT sensor is located on coolant housing at rear of cylinder head and contains Dark Gray 2-pin electrical connector with Green/Red and Blue/Black wires. Connect jumper wire between both terminals on electrical connector for ECT sensor.
4. Turn ignition on. Using hand-held tester or scan tool, read engine coolant temperature for ECT sensor. If displayed engine coolant temperature is less than 284°F (140°C), go to next step. If displayed engine coolant temperature is 284°F (140°C) or more, check for defective electrical connections at ECT sensor and electrical connector. If electrical connections are defective, repair as necessary. If electrical connections are okay, replace ECT sensor. See «ENGINE COOLANT TEMPERATURE SENSOR»(ref-133226-S40099607872002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
5. Turn ignition off. Remove jumper wire. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Ensure electrical connectors at ECM are securely installed so all terminals in electrical connectors are contacting terminals in ECM.
6. Ensure electrical connector at ECT sensor is still disconnected. Connect jumper wire between terminals No. 12 (Green/Red wire) and No. 18 (Blue/Black wire) at ECM electrical connector E7 with all electrical connectors installed on ECM. (Scheme 99) This is the THW and E2 terminals on ECM.
7. Turn ignition on. Using hand-held tester or scan tool, read engine coolant temperature for ECT sensor. If displayed engine coolant temperature is 284°F (140°C) or more, repair open Green/Red wire or Blue/Black wire between ECT sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If displayed engine coolant temperature is not 284°F (140°C) or more, replace ECM.
8. Turn ignition off. Disconnect electrical connector at ECT sensor. ECT sensor is located on coolant housing at rear of cylinder head and contains Dark Gray 2-pin electrical connector with Green/Red and Blue/Black wires.
9. Turn ignition on. Using hand-held tester or scan tool, read engine coolant temperature for ECT sensor. If displayed engine coolant temperature is not -40°F (-40°C), go to next step. If displayed engine coolant temperature is -40°F (-40°C), replace ECT sensor. See «ENGINE COOLANT TEMPERATURE SENSOR»(ref-133226-S40099607872002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
10. Turn ignition off. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Disconnect ECM electrical connector E7. (Scheme 99) Ensure electrical connector is still disconnected at ECT sensor.
11. Turn ignition on. Using hand-held tester or scan tool, read engine coolant temperature for ECT sensor. If displayed engine coolant temperature is -40°F (-40°C), repair short in wiring harness and electrical connectors between ECT sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If displayed engine coolant temperature is not -40°F (-40°C), replace ECM.

1. Using Toyota hand-held tester or scan tool, check for any other DTCs. If only DTC P0116 exists, go to next step. If other DTCs exist, diagnose and repair those DTCs first and retest.
2. Remove and inspect cooling system thermostat for damage and proper operation. Thermostat is located behind thermostat housing on driver's side front of timing chain cover, just behind cooling fan. If thermostat is defective, replace thermostat. If thermostat is okay, replace ECT sensor. ECT sensor is located on coolant housing at rear of cylinder head and contains Dark Gray 2-pin electrical connector with Green/Red and Blue/Black Green wires. See «ENGINE COOLANT TEMPERATURE SENSOR»(ref-133226-S40099607872002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. see scheme 1 Turn ignition on and then turn hand-held tester or scan tool on.
2. Using hand-held tester or scan tool, read throttle valve opening percentages with throttle fully closed and fully open. Throttle valve opening percentage should be approximately 10 percent with throttle fully closed and approximately 75 percent with throttle fully open. If throttle valve opening percentages are not within specification, go to next step. If throttle valve opening percentages are within specification, problem is intermittent. Check for defective connections or intermittent problem in wiring between TP sensor and ECM. ECM is located behind glove box. see scheme 2
3. Turn ignition off. Disconnect electrical connector at TP sensor. Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 2 (Green/Yellow wire) at electrical connector for TP. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, go to step 6.
4. Check TP sensor. See «THROTTLE POSITION SENSOR»(ref-133221-S11553571842002021900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If TP sensor is okay, go to next step. If TP sensor is defective, replace TP sensor.
5. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Turn ignition on. Using voltmeter, check voltage between terminals No. 9 (Yellow wire) and No. 18 (Blue/Black wire) at ECM electrical connector E7 with all electrical connectors installed on ECM with throttle fully closed and fully open. (Scheme 99) This is the VTA and E2 terminals on ECM. Voltage should be.3-.8 volt with throttle fully closed and 3.2-4.9 volts with throttle fully open. If voltages are within specification, replace ECM. If voltages are not within specification, repair open or short in Yellow wire and electrical connectors between TP sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article.
6. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Ensure ignition is on. Using voltmeter, check voltage between terminals No. 2 (Green/Yellow wire) and No. 18 (Blue/Black wire) at ECM electrical connector E7 with all electrical connectors installed on ECM. (Scheme 99) This is the VC and E2 terminals on ECM. Voltage should be 4.5-5.5 volts. If voltage is not within specification, replace ECM. If voltage is within specification, repair open in Green/Yellow wire and electrical connectors between TP sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article.

Circuit Description

Throttle Position (TP) sensor is a variable resistor located on throttle body which monitors throttle opening and delivers input signals to Engine Control Module (ECM). ECM uses input signals for determining vehicle driving conditions and adjusts air/fuel mixture accordingly. DTC is set after vehicle speed is more than 19 MPH once and TP sensor output voltage is out of range while vehicle speed is 0-19 MPH. Possible cause is defective TP sensor.

Diagnostic Aids

This DTC uses two-trip detection logic. Using hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.

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. Test drive confirmation may be performed to operate vehicle under conditions which may cause DTC to be set. When performing test drive confirmation, procedures must be performed exactly as listed or the malfunction may not be detected. If Toyota hand-held tester is available, 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 at driver's side of instrument panel. see scheme 1 Switch hand-held tester from NORMAL mode to CHECK mode.
3. Start engine and warm engine to normal operating temperature. Ensure all accessories are off. Drive vehicle at 38-75 MPH with engine speed of 1600-3200 RPM for 3-5 minutes. 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. Ensure all accessories are off. Drive vehicle at 38-75 MPH with engine speed of 1600-3200 RPM for 3-5 minutes.
5. Turn ignition off. Repeat step 4 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.

Scheme 100

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. Check for any loose or defective PCV valve hose connections. PCV valve is located on top of valve cover at rear corner of valve cover. If PCV valve hose connections are okay, go to next step. If PCV valve hose connections are defective, repair or replace components as necessary.
3. 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.
4. Using hand-held tester or scan tool, monitor 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 within specification. See «AIR/FUEL SENSOR OUTPUT VOLTAGE SPECIFICATIONS»(ref-133217-S14409061682002021900000) 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 11. 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.
5. Check for open and short in wiring harness and electrical connectors between A/F sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. A/F sensor is located on exhaust pipe in front of catalytic converter. ECM is located behind glove box. see scheme 2 If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
6. Disconnect electrical connector for A/F sensor. Using ohmmeter, check resistance for heater on A/F sensor between +B and HT terminals on electrical connector for A/F sensor. (Scheme 100) Resistance should be.8-1.4 ohms at 68°F (20°C) and 1.8-3.2 ohms at 1472°F (800°C). If resistance is within specification, go to next step. If resistance is not within specification, replace A/F sensor. See «AIR/FUEL SENSOR»(ref-133226-S17977439112002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
7. Ensure engine 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.
8. Check fuel pressure. See «FUEL PRESSURE»(ref-133196-S18329124162002021900000) under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If fuel pressure is within specification, go to next step. If fuel pressure is not within specification, repair fuel system as necessary.
9. Check operation of fuel injectors. See «FUEL CONTROL»(ref-133221-S20189354462002021900000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be 71-86 cc (.24-.29 oz.) within 15 seconds and difference in volume between each fuel injector should be less than 15 cc (.05 oz.). Fuel injectors should not leak more than one drop every 12 minutes. If fuel injectors are okay, go to next step. If fuel injectors are defective, replace fuel injectors as necessary.
10. Check exhaust system for leaks. If no exhaust leak exists, replace A/F sensor. See «AIR/FUEL SENSOR»(ref-133226-S17977439112002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. If exhaust leak exists, repair exhaust system as necessary.
11. Using Toyota hand-held tester or scan tool, clear DTCs from ECM. Perform test drive confirmation and then go to next step. See «TEST DRIVE CONFIRMATION»(ref-133217-S18020408342002021900000).
12. Recheck for DTCs. If DTC P0125 does not exist, go to next step. If DTC P0125 exists, replace ECM. ECM is located behind glove box. see scheme 2
13. Verify if vehicle ran out of fuel. If vehicle ran out of fuel, DTC P0125 was caused by the vehicle running out of fuel. If vehicle did not run out of fuel, problem is intermittent. Check for defective connections or intermittent problem in wiring. ECM is located behind glove box. see scheme 2

1. Remove and inspect cooling system thermostat for damage and proper operation. Thermostat is located behind thermostat housing on driver's side front of timing chain cover, just behind cooling fan. If thermostat is okay, go to next step. If thermostat is defective, replace thermostat.
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. ECM is located behind glove box. see scheme 2

Heated oxygen sensor monitors exhaust gas oxygen content and delivers input signals to Engine Control Module (ECM). Heated oxygen sensor is located on exhaust pipe, behind catalytic converter. Heated oxygen sensor may also be referred to as oxygen sensor (bank No. 1 sensor No. 2). ECM uses input signals to determine fuel injection system operation. DTC is set when heated oxygen sensor output voltage remains at .40 volt or more, or .60 volt or less when vehicle is driven at 25 MPH with engine at normal operating temperature. Possible causes are

1. Heated oxygen sensor circuit is open or shorted.
2. Defective heated oxygen sensor.
3. Exhaust system leak.

This DTC uses two-trip detection logic. Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.

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 and short in wiring harness and electrical connectors between heated oxygen sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. Heated oxygen sensor is located on exhaust pipe, behind catalytic converter. ECM is located behind glove box. see scheme 2 If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair 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 output voltage while quickly accelerating engine to 4000 RPM 3 consecutive times.
4. Output voltage should fluctuate from.40 volt or less to.60 volt or more. If output voltage is within specification, problem is intermittent. Check for defective connections or intermittent problem in wiring between heated oxygen sensor and ECM. If output voltage is not within specification, check exhaust system for leaks. If exhaust leak exists, repair exhaust system as necessary. If no exhaust leak exists, replace heated oxygen sensor. See «HEATED OXYGEN SENSOR»(ref-133226-S37802845312002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

1. Test drive confirmation may be performed to operate vehicle under conditions which may cause DTC to be set. When performing test drive confirmation, procedures must be performed exactly as listed or the malfunction may not be detected. If Toyota hand-held tester is available, 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 at driver's side of instrument panel. see scheme 1 Switch hand-held tester from NORMAL mode to CHECK mode.
3. Start engine and warm engine to normal operating temperature. Ensure all accessories are off. Drive vehicle at 38-75 MPH with engine speed of 1600-3200 RPM for 3-5 minutes. 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. Ensure all accessories are off. Drive vehicle at 38-75 MPH with engine speed of 1600-3200 RPM for 3-5 minutes.
5. Turn ignition off. Repeat step 4 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.

1. Ensure engine 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.
2. Check for any loose or defective PCV valve hose connections. PCV valve is located on top of valve cover at rear corner of valve cover. If PCV valve hose connections are okay, go to next step. If PCV valve hose connections are defective, repair or replace components as necessary.
3. Check operation of fuel injectors. See «FUEL CONTROL»(ref-133221-S20189354462002021900000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be 71-86 cc (.24-.29 oz.) within 15 seconds and difference in volume between each fuel injector should be less than 15 cc (.05 oz.). Fuel injectors should not leak more than one drop every 12 minutes. If fuel injectors are okay, go to next step. If fuel injectors are defective, replace fuel injectors as necessary.
4. Check Mass Airflow (MAF) meter and Engine Coolant Temperature (ECT) sensor. MAF meter may also be referred to as airflow meter. See «AIRFLOW METER»(ref-133221-S02163573182002021900000) and «ENGINE COOLANT TEMPERATURE SENSOR»(ref-133221-S39622789122002021900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If MAF meter and ECT sensor are okay, go to next step. If MAF meter or ECT sensor is defective, replace components as necessary. See «AIRFLOW METER»(ref-133226-S15443530482002021900000) or «ENGINE COOLANT TEMPERATURE SENSOR»(ref-133226-S40099607872002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
5. Check ignition system by performing spark test. See «SPARK TEST»(ref-133196-S06466806432002021900000) under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If ignition system operates properly and spark exist, go to next step. If ignition system does not operate properly and spark does not exist, repair ignition system as necessary.
6. Check fuel pressure. See «FUEL PRESSURE»(ref-133196-S18329124162002021900000) under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If fuel pressure is within specification, go to next step. If fuel pressure is not within specification, repair fuel system as necessary.
7. Check exhaust system for leaks. If no exhaust leak exists, go to next step. If exhaust leak exists, repair exhaust system as necessary.
8. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. see scheme 1 Start engine and maintain engine speed at 2500 RPM for about 90 seconds to fully warm the A/F sensor. Allow engine to idle.
9. Using hand-held tester or scan tool, monitor 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-133217-S39526102452002021900000) 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 11. 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.
10. Check for open and short in wiring harness and electrical connectors between A/F sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. A/F sensor is located on exhaust pipe in front of catalytic converter. ECM is located behind glove box. see scheme 2 If wiring harness and electrical connectors are okay, replace A/F sensor. See «AIR/FUEL SENSOR»(ref-133226-S17977439112002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. If wiring harness or electrical connector is defective, repair as necessary.
11. Using Toyota hand-held tester or scan tool, clear DTCs from ECM. Perform test drive confirmation and then go to next step. See «TEST DRIVE CONFIRMATION»(ref-133217-S35747610872002021900000).
12. Recheck for DTCs. If DTC P0171 or P0172 does not exist, go to next step. If DTC P0171 and/or P0172 exist, replace ECM. ECM is located behind glove box. see scheme 2
13. Verify if vehicle ran out of fuel. If vehicle ran out of fuel, DTC P0171 and/or P0172 was caused by the vehicle running out of fuel. If vehicle did not run out of fuel, problem is intermittent. Check for defective connections or intermittent problem in wiring. ECM is located behind glove box. see scheme 2

Engine Control Module (ECM) uses input signals provided by crankshaft and camshaft position sensors to monitor the changes in crankshaft rotation. If engine speed rate changes enough to equal a preset number, a misfire is detected and Malfunction Indicator Light (MIL) is illuminated. If misfire rate is great enough and driving conditions will cause catalytic converter damage or overheating, the MIL will blink when misfire is occurring. DTC is set when misfiring of random cylinders is detected during any particular 200 or 1000 revolutions. Possible causes are

1. Open or short in engine wiring harness.
2. Defective connections at ECM or component.
3. Disconnected, restricted or damaged vacuum hose(s).
4. Defective Positive Crankcase Ventilation (PCV) valve hose or connection.
5. Ignition system malfunction.
6. Defective fuel injector(s).
7. Improper fuel pressure.
8. Defective EGR system (2.7L 3RZ-FE) only.
9. Defective Mass Airflow (MAF) meter.
10. Defective Engine Coolant Temperature (ECT) sensor.
11. Improper engine compression.
12. Improper valve clearance.
13. Improper valve timing.

When 2 or more DTCs for misfiring cylinder are recorded repeatedly and DTC P0300 does not exist, it indicates misfires were detected and recorded at different times. If misfire cannot be reproduced, the reason may be because vehicle was driven with a lack of fuel, improper fuel, fouled spark plug or etc. Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected. If COOLANT TEMP displayed in freeze frame data is less than 176°F (80°C), there is a possibility that misfire only exists during warm-up.

If oscilloscope is available, fuel injector operation on misfiring cylinder may be checked by reading the fuel injector signal waveform pattern and fuel injector duration signal waveform pattern which may be checked by connecting oscilloscope between terminal No. 21 (White/Black wire) at ECM electrical connector E8 and fuel injector driver terminal at ECM with engine idling. Terminal No. 21 is the E01 terminal on ECM. For ECM electrical connector terminal identification (Scheme 99) For fuel injector driver identification, see IDENTIFYING ECM FUEL INJECTOR DRIVER TERMINALS table. ECM is located behind glove box. see scheme 2 Fuel injector signal waveform pattern and fuel injector duration signal waveform pattern should be properly displayed within proper intervals. (Scheme 101)

1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. see scheme 1 Check for any DTCs and read FREEZE FRAME data. Record DTCs and freeze frame data. If using hand-held tester, switch hand-held tester to CHECK mode.
2. 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.
3. Allow engine to idle for at least 3 1/2 minutes and then drive vehicle at specified engine speeds for specified amount of time. See «DRIVING PATTERN»(ref-133217-S23990887712002021900000) 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 Engine RPM Specified Time 1000 3 Minutes Or More 2000 1 1/2 Minutes Or More 3000 1 Minute Or More

Scheme 101

1. Check vacuum hoses for leaks, restrictions and proper routing. See «VACUUM DIAGRAMS»(ref-133225) article for proper vacuum hose routing. Also, check engine wiring harness and electrical connectors for damage or poor connections. If no problems exist, go to next step. If problem exists, repair as necessary and perform «TEST DRIVE CONFIRMATION»(ref-133217-S33010308562002021900000).
2. Check for any loose or defective PCV valve hose connections. PCV valve is located on top of valve cover at rear corner of valve cover. If PCV valve hose connections are okay, go to next step. If PCV valve hose connections are defective, repair or replace components as necessary.
3. Remove spark plug for misfiring cylinder. Ensure no carbon deposits exist, spark plug is not fouled and spark plug gap is.043" (1.10 mm). Check ignition system by performing spark test. See «SPARK TEST»(ref-133196-S06466806432002021900000) under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If ignition system operates properly and spark exist, go to next step. If ignition system does not operate properly and spark does not exist, repair ignition system as necessary.
4. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Turn ignition on. Using voltmeter, check voltage between body ground and fuel injector driver terminal for misfiring cylinder at appropriate ECM electrical connector. See «IDENTIFYING ECM FUEL INJECTOR DRIVER TERMINALS»(ref-133217-S29605061692002021900000) table. For ECM electrical connector terminal identification (Scheme 99) If voltage is not 9-14 volts at fuel injector driver terminal, go to next step. If voltage is 9-14 volts at fuel injector driver terminal, go to step 7. IDENTIFYING ECM FUEL INJECTOR DRIVER TERMINALS Fuel Injector No. (1) ECM Electrical Connector & Terminal (2) Wire Color 1 E8 Terminal No. 1 White/Red 2 E8 Terminal No. 2 White 3 E8 Terminal No. 3 Red 4 E8 Terminal No. 4 Red/Blue (1) Fuel injector No. 1 is at timing chain end of engine and fuel injector No. 4 is at flywheel end of engine. (2) For ECM electrical connector terminal identification (Scheme 99)
5. Disconnect electrical connector at fuel injector on misfiring cylinder. Using ohmmeter, check resistance between electrical terminals on fuel injector. Resistance should be 12-16 ohms at 68°F (20°C). If resistance is within specification, go to next step. If resistance is not within specification, replace fuel injector. See «FUEL RAILS & FUEL INJECTORS»(ref-133226-S05944270142002021900000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
6. Check for open and short in wiring harness and electrical connectors between fuel injector on misfiring cylinder and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness or electrical connector is defective, repair as necessary. If wiring harness and electrical connectors are okay, it may be necessary to check for open and short in wiring harness and electrical connectors in fuel injector power supply circuit. See «WIRING DIAGRAMS»(ref-133228) article.
7. Check fuel pressure. See «FUEL PRESSURE»(ref-133196-S18329124162002021900000) under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If fuel pressure is within specification, go to next step. If fuel pressure is not within specification, repair fuel system as necessary.
8. Check operation of fuel injector on misfiring cylinder. See «FUEL CONTROL»(ref-133221-S20189354462002021900000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be 71-86 cc (.24-.29 oz.) within 15 seconds and difference in volume between each fuel injector should be less than 15 cc (.05 oz.). Fuel injectors should not leak more than one drop every 12 minutes. If fuel injectors are okay, go to next step. If fuel injectors are defective, replace fuel injectors as necessary.
9. On 2.4L 2RZ-FE, go to next step. On 2.7L 3RZ-FE, check EGR system operation by performing system check. See «EXHAUST GAS RECIRCULATION SYSTEM»(ref-133221-S10030336882002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If EGR system operates properly, go to next step. If EGR system does not operate properly, repair EGR system as necessary.
10. On all models, check Mass Airflow (MAF) meter and Engine Coolant Temperature (ECT) sensor. MAF meter may also be referred to as airflow meter. See «AIRFLOW METER»(ref-133221-S02163573182002021900000) and «ENGINE COOLANT TEMPERATURE SENSOR»(ref-133221-S39622789122002021900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If MAF meter and ECT sensor are okay, go to next step. If MAF meter or ECT sensor is defective, replace components as necessary. See «AIRFLOW METER»(ref-133226-S15443530482002021900000) or «ENGINE COOLANT TEMPERATURE SENSOR»(ref-133226-S40099607872002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
11. Check engine compression on misfiring cylinder. See «MECHANICAL INSPECTION»(ref-133196-S31400215492002021900000) under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Check valve clearance on misfiring cylinder. See «VALVE CLEARANCE»(ref-133193-S32906693182002021900000) under ENGINE MECHANICAL in ON-VEHICLE ADJUSTMENTS - 4-CYLINDER article. Check valve timing. See appropriate article in ENGINES. Repair engine as necessary.

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

1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. see scheme 1
2. Start engine and warm engine to normal operating temperature. Ensure all accessories are off. Drive vehicle at 43-56 MPH for at least 3 minutes and then allow engine to idle for about 2 minutes.
3. Repeat step 2 again. Check READINESS TESTS mode on hand-held tester or scan tool. If COMPL is displayed and Malfunction Indicator Light (MIL) does not illuminate, system is normal. If INCOMPL is displayed and MIL does not illuminate, repeat step 2 several times and recheck READINESS TESTS mode on hand-held tester or scan tool. If INCOMPL is displayed, the system check is not complete or there is a malfunction in the EGR system. If malfunction exists, the MIL will illuminate and DTC is set. If MIL does not illuminate, malfunction does not exist.

Scheme 102

Scheme 103

Scheme 104

1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step 19.
2. Connect hand-held tester to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. see scheme 1 Turn ignition on and then turn hand-held tester on.
3. Using hand-held tester, read EGR gas temperature. If displayed EGR gas temperature is less than 50°F (10°C), go to next step. If displayed EGR gas temperature is 50°F (10°C) or more, go to step 9.
4. Turn ignition off. Disconnect electrical connector at EGR gas temperature sensor. EGR gas temperature sensor is located near EGR valve and contains Dark Gray 2-pin electrical connector with Pink/Blue and Blue/Black wires. (Scheme 102) Connect jumper wire between both terminals on electrical connector for EGR gas temperature sensor.
5. Turn ignition on. Using hand-held tester, read EGR gas temperature. If displayed EGR gas temperature is not 318.7°F (159.3°C), go to next step. If displayed EGR gas temperature is 318.7°F (159.3°C), check for defective electrical connections at EGR gas temperature sensor and electrical connector. If electrical connections are defective, repair as necessary. If electrical connections are okay, replace EGR gas temperature sensor. See «EGR GAS TEMPERATURE SENSOR»(ref-133226-S40019758142002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
6. Turn ignition off. Remove jumper wire. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Ensure electrical connectors at ECM are securely installed so all terminals in electrical connectors are contacting terminals in ECM.
7. Ensure electrical connector at EGR gas temperature sensor is still disconnected. Connect jumper wire between terminals No. 18 (Blue/Black wire) and No. 19 (Pink/Blue wire) at ECM electrical connector E7 with all electrical connectors installed on ECM. (Scheme 99) This is the E2 and THG terminals on ECM.
8. Turn ignition on. Using hand-held tester, read EGR gas temperature. If displayed EGR gas temperature is 318.7°F (159.3°C), repair open in Blue/Black wire or Pink/Blue wire between EGR gas temperature sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If displayed EGR gas temperature is not 318.7°F (159.3°C), replace ECM.
9. Check for disconnected, defective or restricted vacuum hose at EGR valve. If vacuum hose is okay and properly connected, go to next step. If vacuum hose is disconnected, defective or restricted, reconnect or replace vacuum hose as necessary.
10. Disconnect vacuum hoses at EGR VSV. EGR VSV is located on bracket, near throttle body and contains Green 2-pin electrical connector with White/Red and Red/Black wires. (Scheme 103)
11. Ensure ignition and hand-held tester are on. Select ACTIVE TEST mode on hand-held tester to operate EGR VSV. Apply air pressure to port "E" on EGR VSV. (Scheme 104) Ensure air flows from port "F" when EGR VSV is off and does not from port "F" when EGR VSV is on. If EGR VSV does not operate as specified, turn ignition off. Go to next step. If EGR VSV operates as specified, turn ignition off. Go to step 15.
12. Disconnect EGR VSV electrical connector. Using ohmmeter, check that continuity exists between electrical terminals on EGR VSV and resistance is 33-39 ohms at 68°F (20°C). Using ohmmeter, ensure no continuity exists between each electrical terminal and body of EGR VSV. If EGR VSV resistance is within specification and no continuity exists between electrical terminal and body of EGR VSV, go to next step. If resistance is not within specification or if continuity exists between electrical terminal and body of EGR VSV, replace EGR VSV.
13. To test EGR VSV operation, apply air pressure to port "E" on EGR VSV. (Scheme 104) Ensure air does not flow from port "F". Apply battery voltage and ground to electrical terminals on EGR VSV. Apply air pressure to port "E" on EGR VSV. Ensure air flows from port "F". If EGR VSV operates properly, go to next step. If EGR VSV does not operate properly, replace EGR VSV.
14. Check for open and short in wiring harness and electrical connectors between EFI main relay and EGR VSV, and between EGR VSV and ECM. See «WIRING DIAGRAMS»(ref-133228) article. EFI main relay may also be referred to as EFI relay. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment. Repair wiring harness or electrical connector as necessary.
15. Check EGR system operation by performing system check. See «EXHAUST GAS RECIRCULATION SYSTEM»(ref-133221-S10030336882002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If EGR system operates properly, go to next step. If EGR system does not operate properly, repair EGR system as necessary.
16. Check operation of EGR vacuum modulator. See «EGR VACUUM MODULATOR»(ref-133221-S03202445342002021900000) under EXHAUST GAS RECIRCULATION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If EGR vacuum modulator operates properly, go to next step. If EGR vacuum modulator does not operate properly, replace EGR vacuum modulator.
17. Check EGR valve. See «EGR VALVE»(ref-133221-S24033964642002021900000) under EXHAUST GAS RECIRCULATION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If EGR valve is okay, go to next step. If EGR valve is defective, replace EGR valve. See «EGR VALVE»(ref-133226-S09543119472002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
18. Ensure all components are connected and hand-held tester is still connected to DLC No. 3. Start engine and allow engine to idle. Select ACTIVE TEST mode on hand-held tester to operate EGR system. Accelerate engine to 4000 RPM for 3 minutes and then use hand-held tester to read EGR gas temperature with EGR system on and engine at 4000 RPM. If displayed EGR gas temperature 212°F (100°C) or more, replace ECM. If displayed EGR gas temperature is less than 212°F (100°C), replace EGR gas temperature sensor. See «EGR GAS TEMPERATURE SENSOR»(ref-133226-S40019758142002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
19. Disconnect electrical connector at EGR gas temperature sensor. EGR gas temperature sensor is located near EGR valve and contains Dark Gray 2-pin electrical connector with Pink/Blue and Blue/Black wires. (Scheme 102)
20. Using ohmmeter, check resistance between both electrical terminals on EGR gas temperature sensor. Resistance should be 600,000 ohms or less. If open exists in EGR gas temperature sensor, resistance will be 720,000 ohms or more. If resistance is within specification, go to next step. If resistance is not within specification, replace EGR gas temperature sensor. See «EGR GAS TEMPERATURE SENSOR»(ref-133226-S40019758142002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
21. Ensure electrical connector is still disconnected at EGR gas temperature sensor. Turn ignition on. Using voltmeter, check voltage between both electrical terminals on wiring harness side of electrical connector for EGR gas temperature sensor. Voltage should be 4.5-5.5 volts. If voltage is not within specification, go to next step. If voltage is within specification, go to step 23.
22. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Ensure ignition is on. Using voltmeter, check voltage between terminals No. 18 (Blue/Black wire) and No. 19 (Pink/Blue wire) at ECM electrical connector E7 with all electrical connectors installed on ECM. (Scheme 99) This is the E2 and THG terminals on ECM. Voltage should be 4.5-5.5 volts. If voltage is not within specification, replace ECM. If voltage is within specification, check for open and short in wiring harness and electrical connectors between EGR gas temperature sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. Repair wiring harness and electrical connectors as necessary.
23. Check for disconnected, defective or restricted vacuum hose at EGR valve. If vacuum hose is okay and properly connected, go to next step. If vacuum hose is disconnected, defective or restricted, reconnect or replace vacuum hose as necessary.
24. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Ensure ignition is off. Disconnect ECM electrical connector E7. (Scheme 99)
25. Disconnect vacuum hoses at EGR VSV. EGR VSV is located on bracket, near throttle body and contains Green 2-pin electrical connector with White/Red and Red/Black wires. (Scheme 103) Turn ignition on. Connect jumper wire between body ground and terminal No. 5 (Red/Black wire) at ECM electrical connector E7 to operate EGR VSV. (Scheme 99)Apply air pressure to port "E" on EGR VSV. (Scheme 104) Ensure air flows from port "F" when EGR VSV is on with jumper wire connected and does not from port "F" when EGR VSV is off with jumper wire disconnected. If EGR VSV does not operate as specified, turn ignition off. Go to next step. If EGR VSV operates as specified, turn ignition off. Go to step 29.
26. Disconnect electrical connector at EGR VSV. Using ohmmeter, check that continuity exists between electrical terminals on EGR VSV and resistance is 33-39 ohms at 68°F (20°C). Using ohmmeter, ensure no continuity exists between each electrical terminal and body of EGR VSV. If EGR VSV resistance is within specification and no continuity exists between electrical terminal and body of EGR VSV, go to next step. If resistance is not within specification or if continuity exists between electrical terminal and body of EGR VSV, replace EGR VSV.
27. To test EGR VSV operation, apply air pressure to port "E" on EGR VSV. (Scheme 104) Ensure air does not flow from port "F". Apply battery voltage and ground to electrical terminals on EGR VSV. Apply air pressure to port "E" on EGR VSV. Ensure air flows from port "F". If EGR VSV operates properly, go to next step. If EGR VSV does not operate properly, replace EGR VSV.
28. Check for open and short in wiring harness and electrical connectors between EFI main relay and EGR VSV, and between EGR VSV and ECM. See «WIRING DIAGRAMS»(ref-133228) article. EFI main relay may also be referred to as EFI relay. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment. Repair wiring harness or electrical connector as necessary.
29. Check EGR system operation by performing system check. See «EXHAUST GAS RECIRCULATION SYSTEM»(ref-133221-S10030336882002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If EGR system operates properly, go to next step. If EGR system does not operate properly, repair EGR system as necessary.
30. Check operation of EGR vacuum modulator. See «EGR VACUUM MODULATOR»(ref-133221-S03202445342002021900000) under EXHAUST GAS RECIRCULATION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If EGR vacuum modulator operates properly, go to next step. If EGR vacuum modulator does not operate properly, replace EGR vacuum modulator.
31. Check EGR valve. See «EGR VALVE»(ref-133221-S24033964642002021900000) under EXHAUST GAS RECIRCULATION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If EGR valve is okay, go to next step. If EGR valve is defective, replace EGR valve. See «EGR VALVE»(ref-133226-S09543119472002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
32. Ensure EGR gas temperature sensor electrical connector is disconnected. Start engine and allow engine to idle. Ensure engine is at normal operating temperature. Disconnect EGR VSV electrical connector.
33. Accelerate engine to 4000 RPM for at least 3 minutes and use ohmmeter to check resistance between electrical terminals on EGR gas temperature sensor with engine at 4000 RPM. Resistance should be 4300 ohms or less. If resistance is within specification, shut engine off. Replace ECM. If resistance is not with specification, shut engine off. Replace EGR gas temperature sensor. See «EGR GAS TEMPERATURE SENSOR»(ref-133226-S40019758142002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. see scheme 1
2. Start engine and warm engine to normal operating temperature. Ensure all accessories are off. Drive vehicle at 43-56 MPH for at least 3 minutes and then allow engine to idle for about 2 minutes.
3. Repeat step 2 again. Check READINESS TESTS mode on hand-held tester or scan tool. If COMPL is displayed and Malfunction Indicator Light (MIL) does not illuminate, system is normal. If INCOMPL is displayed and MIL does not illuminate, repeat step 2 several times and recheck READINESS TESTS mode on hand-held tester or scan tool. If INCOMPL is displayed, the system check is not complete or there is a malfunction in the EGR system. If malfunction exists, the MIL will illuminate and DTC is set. If MIL does not illuminate, malfunction does not exist.

1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step 13.
2. Connect hand-held tester to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. see scheme 1 Turn ignition on and then turn hand-held tester on.
3. Using hand-held tester, read EGR gas temperature. If displayed EGR gas temperature is more than 302°F (150°C), go to next step. If displayed EGR gas temperature is 302°F (150°C) or less, go to step 8.
4. Turn ignition off. Disconnect electrical connector at EGR gas temperature sensor. EGR gas temperature sensor is located near EGR valve and contains Dark Gray 2-pin electrical connector with Pink/Blue and Blue/Black wires. (Scheme 102)
5. Turn ignition on. Using hand-held tester, read EGR gas temperature. If displayed EGR gas temperature is not 37.6°F (3.1°C), go to next step. If displayed EGR gas temperature is 37.6°F (3.1°C), replace EGR gas temperature sensor. See «EGR GAS TEMPERATURE SENSOR»(ref-133226-S40019758142002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
6. Turn ignition off. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Disconnect ECM electrical connector E7. (Scheme 99)
7. Ensure electrical connector at EGR gas temperature sensor is still disconnected. Turn ignition on. Using hand-held tester, read EGR gas temperature. If displayed EGR gas temperature is not 37.6°F (3.1°C), replace ECM. If displayed EGR gas temperature is 37.6°F (3.1°C), repair short in wiring harness and electrical connectors between EGR gas temperature sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article.
8. Disconnect vacuum hoses at EGR VSV. EGR VSV is located on bracket, near throttle body and contains Green 2-pin electrical connector with White/Red and Red/Black wires. (Scheme 103)
9. Turn ignition and hand-held tester are on. Select ACTIVE TEST mode on hand-held tester to operate EGR VSV. Apply air pressure to port "E" on EGR VSV. (Scheme 104) Ensure air flows from port "F" when EGR VSV is off and does not from port "F" when EGR VSV is on. If EGR VSV does not operate as specified, turn ignition off. Go to next step. If EGR VSV operates as specified, check EGR valve. See «EGR VALVE»(ref-133221-S24033964642002021900000) under EXHAUST GAS RECIRCULATION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Replace EGR valve if defective. See «EGR VALVE»(ref-133226-S09543119472002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
10. Disconnect electrical connector at EGR VSV. Using ohmmeter, check that continuity exists between electrical terminals on EGR VSV and resistance is 33-39 ohms at 68°F (20°C). Using ohmmeter, ensure no continuity exists between each electrical terminal and body of EGR VSV. If EGR VSV resistance is within specification and no continuity exists between electrical terminal and body of EGR VSV, go to next step. If resistance is not within specification or if continuity exists between electrical terminal and body of EGR VSV, replace EGR VSV.
11. To test EGR VSV operation, apply air pressure to port "E" on EGR VSV. (Scheme 104) Ensure air does not flow from port "F". Apply battery voltage and ground to electrical terminals on EGR VSV. Apply air pressure to port "E" on EGR VSV. Ensure air flows from port "F". If EGR VSV operates properly, go to next step. If EGR VSV does not operate properly, replace EGR VSV.
12. Check for open and short in wiring harness and electrical connectors between EFI main relay and EGR VSV, and between EGR VSV and ECM. See «WIRING DIAGRAMS»(ref-133228) article. EFI main relay may also be referred to as EFI relay. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment. Repair wiring harness or electrical connector as necessary.
13. Disconnect electrical connector at EGR gas temperature sensor. EGR gas temperature sensor is located near EGR valve and contains Dark Gray 2-pin electrical connector with Pink/Blue and Blue/Black wires. (Scheme 102)
14. Using ohmmeter, check resistance between both electrical terminals on EGR gas temperature sensor. Resistance should be 2500 ohms or more not immediately after driving vehicle. If short exists in EGR gas temperature sensor, resistance will be 200 ohms or less. If resistance is within specification, go to next step. If resistance is not within specification, replace EGR gas temperature sensor. See «EGR GAS TEMPERATURE SENSOR»(ref-133226-S40019758142002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
15. Check for short in wiring harness and electrical connectors between EGR gas temperature sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind glove box. see scheme 2 If wiring harness and electrical connector are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
16. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Ensure ignition is off. Disconnect ECM electrical connector E7. (Scheme 99)
17. Disconnect vacuum hoses at EGR VSV. EGR VSV is located on bracket, near throttle body and contains Green 2-pin electrical connector with White/Red and Red/Black wires. (Scheme 103)
18. Turn ignition on. Connect jumper wire between body ground and terminal No. 5 (Red/Black wire) at ECM electrical connector E7 to operate EGR VSV. (Scheme 99) Apply air pressure to port "E" on EGR VSV. (Scheme 104) Ensure air flows from port "F" when EGR VSV is on with jumper wire connected and does not from port "F" when EGR VSV is off with jumper wire disconnected. If EGR VSV does not operate as specified, turn ignition off. Go to next step. If EGR VSV operates properly, check EGR valve for being stuck open. See «EGR VALVE»(ref-133221-S24033964642002021900000) under EXHAUST GAS RECIRCULATION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Replace EGR valve if defective. See «EGR VALVE»(ref-133226-S09543119472002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
19. Disconnect electrical connector at EGR VSV. Using ohmmeter, check that continuity exists between electrical terminals on EGR VSV and resistance is 33-39 ohms at 68°F (20°C). Using ohmmeter, ensure no continuity exists between each electrical terminal and body of EGR VSV. If EGR VSV resistance is within specification and no continuity exists between electrical terminal and body of EGR VSV, go to next step. If resistance is not within specification or if continuity exists between electrical terminal and body of EGR VSV, replace EGR VSV.
20. To test EGR VSV operation, apply air pressure to port "E" on EGR VSV. (Scheme 104) Ensure air does not flow from port "F". Apply battery voltage and ground to electrical terminals on EGR VSV. Apply air pressure to port "E" on EGR VSV. Ensure air flows from port "F". If EGR VSV operates properly, go to next step. If EGR VSV does not operate properly, replace EGR VSV.
21. Check for open and short in wiring harness and electrical connectors between EFI main relay and EGR VSV, and between EGR VSV and ECM. See «WIRING DIAGRAMS»(ref-133228) article. EFI main relay may also be referred to as EFI relay. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment. If wiring harness and connectors are okay, replace ECM. If wiring harness or electrical connector is defective, repair as necessary.

Engine Control Module (ECM) compares waveform pattern of heated Air/Fuel (A/F) sensor located on exhaust pipe in front of catalytic converter with waveform pattern of heated oxygen sensor located on exhaust pipe behind catalytic converter to determine if catalytic converter performance has deteriorated. If catalytic converter is functioning properly, waveform pattern for heated oxygen sensor on exhaust pipe should switch back and forth from rich to lean more slowly than A/F sensor. If both waveform patterns switch at a similar rate, catalytic converter performance has deteriorated. DTC is set when A/F sensor and heated oxygen sensor have nearly the same waveform pattern after engine and catalytic converter are at normal operating temperature and vehicle is driven. Possible causes are

1. Exhaust system leak.
2. Defective A/F sensor.
3. Defective heated oxygen sensor.
4. Defective catalytic converter.

This DTC uses two-trip detection logic. Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.

1. Using Toyota hand-held tester or scan tool, check for any other DTCs. If only DTC P0420 exists, go to next step. If other DTCs exist, diagnose and repair those DTCs first and then retest.
2. Check exhaust system for leaks. If no exhaust leak exists, go to next step. If exhaust leak exists, repair exhaust system as necessary.
3. Disconnect electrical connector for A/F sensor. A/F sensor is located on exhaust pipe in front of catalytic converter. Using ohmmeter, check resistance for heater on A/F sensor between +B and HT terminals on electrical connector for A/F sensor. see scheme 17 Resistance should be.8-1.4 ohms at 68°F (20°C) and 1.8-3.2 ohms at 1472°F (800°C). If resistance is within specification, go to next step. If resistance is not within specification, replace A/F sensor. See «AIR/FUEL SENSOR»(ref-133226-S17977439112002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
4. Disconnect electrical connector for heated oxygen sensor. Heated oxygen sensor is located on exhaust pipe, behind catalytic converter. Using ohmmeter, check resistance between +B and HT terminals on electrical connector for heater on heated oxygen sensor. see scheme 18 Resistance should be 11-16 ohms at 68°F (20°C) and 23-32 ohms at 1472°F (800°C). If resistance is within specification, replace catalytic converter. If resistance is not within specification, replace heated oxygen sensor. See «HEATED OXYGEN SENSOR»(ref-133226-S37802845312002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.

1. Check for any signs of hoses near fuel tank and charcoal canister for modification and for signs of an accident which may have damaged the fuel tank, charcoal canister and fuel inlet pipe which is located between fuel tank and fuel tank cap. Charcoal canister is located near the fuel tank. see scheme 19 If no problems exist, go to next step. If any problems exists, repair or replace components 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. Visually inspect fuel inlet pipe for damage. If fuel inlet pipe is not damaged, go to next step. If fuel inlet pipe is damaged, replace fuel inlet pipe.
6. Check vapor pressure sensor connection at fuel pump. see scheme 19 Check vacuum hoses to charcoal canister, canister closed valve VSV and pressure switching valve VSV for correct installation, loose connections, disconnected hoses and damage. see scheme 19 If no problems exist, go to next step. If any problem exists, repair or replace components as necessary.
7. Check hoses and tubes between fuel tank, fuel inlet pipe and charcoal canister for correct installation, loose connections, being disconnected and damage. see scheme 19 If no problems exist, go to next step. If any problem exists, repair or replace components as necessary.
8. Check charcoal canister for cracks or damage. If charcoal canister is okay, go to next step. If charcoal canister is cracked or damaged, replace charcoal canister.
9. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Ensure ignition is on. Using voltmeter, check voltage between terminals No. 2 (Green/Yellow wire) and No. 18 (Blue/Black wire) at ECM electrical connector E7 with all electrical connectors installed on ECM. (Scheme 99) This is the VC and E2 terminals on ECM. Voltage should be 4.5-5.5 volts. If voltage is within specification, go to next step. If voltage is not within specification, replace ECM.
10. Turn ignition off. Connect voltmeter between terminals No. 8 (Red/Yellow wire) at ECM electrical connector E6 and No. 18 (Blue/Black wire) at ECM electrical connector E7 and with all electrical connectors installed on ECM. (Scheme 99) This is the PTNK and E2 terminals on ECM. Remove fuel tank cap. Turn ignition on and note voltage. Voltage should be 3.3 volts. If voltage is not within specification, go to next step. If voltage is within specification, go to step 12.
11. Check for open and short in wiring harness and electrical connectors between vapor pressure sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness or electrical connector is defective, repair as necessary. If wiring harness and electrical connectors are okay, replace vapor pressure sensor. See «VAPOR PRESSURE SENSOR»(ref-133226-S39173639702002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
12. Inspect fuel tank and overfill check valve on fuel tank for cracks and damage. If fuel tank or overfill check valve are defective, repair or replace components as necessary. If fuel tank and overfill check valve are okay, it is likely that DTC was caused by fuel tank cap not being fully tightened or was improperly installed.

1. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Ensure ignition is on. Using voltmeter, check voltage between terminals No. 2 (Green/Yellow wire) and No. 18 (Blue/Black wire) at ECM electrical connector E7 with all electrical connectors installed on ECM. (Scheme 99) This is the VC and E2 terminals on ECM. Voltage should be 4.5-5.5 volts. If voltage is within specification, go to next step. If voltage is not within specification, replace ECM.
2. Turn ignition off. Connect voltmeter between terminals No. 8 (Red/Yellow wire) at ECM electrical connector E6 and No. 18 (Blue/Black wire) at ECM electrical connector E7 and with all electrical connectors installed on ECM. (Scheme 99) This is the PTNK and E2 terminals on ECM. Remove fuel tank cap. Turn ignition on and note voltage. Voltage should be 3.3 volts. If voltage is not within specification, go to next step. If voltage is within specification, replace ECM.
3. Check for open and short in wiring harness and electrical connectors between vapor pressure sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. Vapor pressure sensor is located on top of the fuel pump on fuel tank. see scheme 19 If wiring harness and electrical connectors are okay, replace vapor pressure sensor. See «VAPOR PRESSURE SENSOR»(ref-133226-S39173639702002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. If wiring harness or electrical connector is defective, repair as necessary.

1. Test drive vehicle and check operation of speedometer. If speedometer operates properly, go to next step. If speedometer does not operate properly, repair speedometer as necessary. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Speedometer may not operate, as input signal from vehicle speed sensor may not be input to instrument cluster. Vehicle speed sensor is located near rear of transmission or transfer case and contains a Black 3-pin electrical connector with Blue, Green/Red and Pink wires. For testing of vehicle speed sensor, see «VEHICLE SPEED SENSOR»(ref-133221-S38948385542002021900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 4-CYLINDER article.
2. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Ensure ignition is off. Disconnect electrical connector at cruise control Electronic Control Unit (ECU). Cruise control ECU is located behind passenger's side kick panel and contains a 16-pin electrical connector.
3. Raise and support vehicle with one rear wheel off the ground. Place transmission in Neutral. Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 21 (Green/Orange wire) at ECM electrical connector E5 while rotating rear wheel. (Scheme 99) This is the SP1 terminal on ECM. Voltage should pulsate. If voltage pulsates, replace ECM. If voltage does not pulsate, repair open or short in Green/Orange wire and electrical connectors between ECM and instrument cluster. See «WIRING DIAGRAMS»(ref-133228) article.

1. Start engine and warm to engine to normal operating temperature. Ensure A/C and all accessories are off. Apply parking brake. Place transmission in Neutral.
2. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. see scheme 1 Note engine speed in less than 5 seconds and at more than 5 seconds. If difference in engine speed is 100 RPM or less, shut engine off. Go to next step. If difference in engine speed is more than 100 RPM, shut engine off. Go to step 9.
3. Check for any loose or defective PCV valve hose connections. PCV valve is located on top of valve cover at rear corner of valve cover. If PCV valve hose connections are okay, go to next step. If PCV valve hose connections are defective, repair or replace components as necessary.
4. Turn ignition off. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Disconnect ECM electrical connector E8. (Scheme 99)
5. Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 15 (Black/Red wire) at ECM electrical connector E8. (Scheme 99) This is the RSD terminal on ECM. Voltage should be 9-14 volts. If voltage is not within specification, go to next step. If voltage is within specification, go to step 7.
6. Check IAC valve operation. See «IDLE AIR CONTROL VALVE»(ref-133221-S10878706512002021900000) under IDLE CONTROL SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If IAC valve is defective, replace IAC valve. If IAC valve is okay, check for open and short in wiring harness and electrical connectors between IAC valve and ECM, and between IAC valve and EFI main relay. See «WIRING DIAGRAMS»(ref-133228) article. EFI main relay may also be referred to as EFI relay. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment. If wiring harness or electrical connector is defective, repair as necessary.
7. Check IAC valve operation. See «IDLE AIR CONTROL VALVE»(ref-133221-S10878706512002021900000) under IDLE CONTROL SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If IAC valve is okay, go to next step. If IAC valve is defective, replace IAC valve.
8. Inspect IAC valve and passages for carbon build-up and blockage. If a problem exist, repair as necessary. If problem does not exist, replace ECM.
9. Ensure engine 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 signal circuit may exist. Check A/C control assembly which may also be referred to as heater control assembly. See MANUAL A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING. Repair as necessary.

1. Test drive confirmation may be performed to operate vehicle under conditions which may cause DTC to be set. When performing test drive confirmation, procedures must be performed exactly as listed or the malfunction may not be detected. If Toyota hand-held tester is available, 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 at driver's side of instrument panel. see scheme 1 Switch hand-held tester from NORMAL mode to CHECK mode.
3. Start engine and warm engine to normal operating temperature. Ensure all accessories are off. Drive vehicle at 38-75 MPH with engine speed of 1600-3200 RPM for 3-5 minutes. 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. Ensure all accessories are off. Drive vehicle at 38-75 MPH with engine speed of 1600-3200 RPM for 3-5 minutes.
5. Turn ignition off. Repeat step 4 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.

1. Using Toyota hand-held tester or scan tool, check for any other DTCs. If only DTC P1130 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 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 within specification. See «AIR/FUEL SENSOR OUTPUT VOLTAGE SPECIFICATIONS»(ref-133217-S24466756742002021900000) 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 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.
4. Check for open and short in wiring harness and electrical connectors between A/F sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. A/F sensor is located on exhaust pipe in front of catalytic converter. ECM is located behind glove box. see scheme 2 If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
5. Disconnect electrical connector for A/F sensor. Using ohmmeter, check resistance for heater on A/F sensor between +B and HT terminals on electrical connector for A/F sensor. see scheme 17 Resistance should be.8-1.4 ohms at 68°F (20°C) and 1.8-3.2 ohms at 1472°F (800°C). If resistance is within specification, go to next step. If resistance is not within specification, replace A/F sensor. See «AIR/FUEL SENSOR»(ref-133226-S17977439112002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
6. Ensure engine 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 PRESSURE»(ref-133196-S18329124162002021900000) under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If fuel pressure is within specification, go to next step. If fuel pressure is not within specification, repair fuel system as necessary.
8. Check operation of fuel injectors. See «FUEL CONTROL»(ref-133221-S20189354462002021900000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be 71-86 cc (.24-.29 oz.) within 15 seconds and difference in volume between each fuel injector should be less than 15 cc (.05 oz.). Fuel injectors should not leak more than one drop every 12 minutes. If fuel injectors are okay, replace A/F sensor. See «AIR/FUEL SENSOR»(ref-133226-S17977439112002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. If fuel injectors are defective, replace fuel injectors as necessary.
9. Using Toyota hand-held tester or scan tool, clear DTCs from ECM. Perform test drive confirmation and then go to next step. See «TEST DRIVE CONFIRMATION»(ref-133217-S08474973312002021900000).
10. Recheck for DTCs. If DTC P1130 does not exist, go to next step. If DTC P1130 exists, replace ECM. ECM is located behind glove box. see scheme 2
11. Verify if vehicle ran out of fuel. If vehicle ran out of fuel, DTC P1130 was caused by the vehicle running out of fuel. If vehicle did not run out of fuel, problem is intermittent. Check for defective connections or intermittent problem in wiring. ECM is located behind glove box. see scheme 2

1. Test drive confirmation may be performed to operate vehicle under conditions which may cause DTC to be set. When performing test drive confirmation, procedures must be performed exactly as listed or the malfunction may not be detected. If Toyota hand-held tester is available, 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 at driver's side of instrument panel. see scheme 1 Switch hand-held tester from NORMAL mode to CHECK mode.
3. Start engine and warm engine to normal operating temperature. Ensure all accessories are off. Drive vehicle at 38-75 MPH with engine speed of 1600-3200 RPM for 3-5 minutes. 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. Ensure all accessories are off. Drive vehicle at 38-75 MPH with engine speed of 1600-3200 RPM for 3-5 minutes.
5. Turn ignition off. Repeat step 4 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.

1. Using Toyota hand-held tester or scan tool, check for any other DTCs. If only DTC P1133 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 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 within specification. See «AIR/FUEL SENSOR OUTPUT VOLTAGE SPECIFICATIONS»(ref-133217-S10483146402002021900000) 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 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.
4. Check for open and short in wiring harness and electrical connectors between A/F sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. A/F sensor is located on exhaust pipe in front of catalytic converter. ECM is located behind glove box. see scheme 2 If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
5. Disconnect electrical connector for A/F sensor. Using ohmmeter, check resistance for heater on A/F sensor between +B and HT terminals on electrical connector for A/F sensor. see scheme 17 Resistance should be.8-1.4 ohms at 68°F (20°C) and 1.8-3.2 ohms at 1472°F (800°C). If resistance is within specification, go to next step. If resistance is not within specification, replace A/F sensor. See «AIR/FUEL SENSOR»(ref-133226-S17977439112002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
6. Ensure engine 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 PRESSURE»(ref-133196-S18329124162002021900000) under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If fuel pressure is within specification, go to next step. If fuel pressure is not within specification, repair fuel system as necessary.
8. Check operation of fuel injectors. See «FUEL CONTROL»(ref-133221-S20189354462002021900000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be 71-86 cc (.24-.29 oz.) within 15 seconds and difference in volume between each fuel injector should be less than 15 cc (.05 oz.). Fuel injectors should not leak more than one drop every 12 minutes. If fuel injectors are okay, replace A/F sensor. See «AIR/FUEL SENSOR»(ref-133226-S17977439112002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. If fuel injectors are defective, replace fuel injectors as necessary.
9. Using Toyota hand-held tester or scan tool, clear DTCs from ECM. Perform test drive confirmation and then go to next step. See «TEST DRIVE CONFIRMATION»(ref-133217-S26368096572002021900000).
10. Recheck for DTCs. If DTC P1133 does not exist, go to next step. If DTC P1133 exists, replace ECM. ECM is located behind glove box. see scheme 2
11. Verify if vehicle ran out of fuel. If vehicle ran out of fuel, DTC P1133 was caused by the vehicle running out of fuel. If vehicle did not run out of fuel, problem is intermittent. Check for defective connections or intermittent problem in wiring. ECM is located behind glove box. see scheme 2

1. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 4 (White wire) at ECM electrical connector E7. (Scheme 99) This is the HAFL terminal on ECM. Voltage should be 9-14 volts. If voltage is not within specification, go to next step. If voltage is within specification, replace ECM.
2. Turn ignition off. Disconnect electrical connector for A/F sensor. A/F sensor is located on exhaust pipe in front of catalytic converter. Using ohmmeter, check resistance for heater on A/F sensor between +B and HT terminals on electrical connector for A/F sensor. see scheme 17 Resistance should be.8-1.4 ohms at 68°F (20°C) and 1.8-3.2 ohms at 1472°F (800°C). If resistance is within specification, go to next step. If resistance is not within specification, replace A/F sensor. See «AIR/FUEL SENSOR»(ref-133226-S17977439112002021900000) under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article.
3. Check for defective wiring harness and electrical connectors between EFI main relay and A/F sensor, and between A/F sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. EFI main relay may also be referred to as EFI relay. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment. Repair wiring harness or electrical connectors as necessary.

1. Check for spark at cylinder No. 1 by performing spark test. See «SPARK TEST»(ref-133196-S06466806432002021900000) under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Cylinder No. 1 is the first cylinder back from timing chain end of engine and uses the ignition coil No. 1. If spark exists, go to next step. If spark does not exist, go to step 4.
2. Check for open and short in Black/Blue and Black/Yellow wires and electrical connectors between ECM and ignition coil No. 1. See «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind glove box. see scheme 2 If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
3. Disconnect electrical connector at ignition coil No. 1. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 10 (Black/Yellow wire) at ECM electrical connector E8. (Scheme 99) This is the IGF terminal on ECM. Voltage should 4.5-5.5 volts. If voltage is within specification, replace ignition coil No. 1. If voltage is not within specification, replace ECM.
4. Check for open and short in Black/Blue wire and electrical connectors between ECM and ignition coil No. 1. See «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind glove box. see scheme 2 If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
5. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Using voltmeter, check voltage between body ground and terminal No. 11 (Black/Blue wire) at ECM electrical connector E8 while cranking engine. (Scheme 99) This is the IGT1 terminal on ECM. Voltage should be more than.1 volt and less than 4.5 volts. If voltage is not within specification, go to next step. If voltage is within specification, go to step 7.
6. Disconnect electrical connector at ignition coil No. 1. Using voltmeter, check voltage between body ground and terminal No. 11 (Black/Blue wire) at ECM electrical connector E8 while cranking engine. (Scheme 99) Voltage should be more than.1 volt and less than 4.5 volts. If voltage is within specification, replace ignition coil No. 1. If voltage is not within specification, replace ECM.
7. Disconnect electrical connector at ignition coil No. 1. Using voltmeter, check voltage between body ground and terminal No. 1 (Black/Red wire) at electrical connector for ignition coil No. 1 with ignition switch in ON and START positions. (Scheme 105) Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, check power supply circuit between ignition switch and ignition coil No. 1. See «WIRING DIAGRAMS»(ref-133228) article.
8. Check for open in Brown wire and electrical connectors between ground and ignition coil No. 1. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, replace ignition coil No. 1. If wiring harness or electrical connector is defective, repair as necessary.

Scheme 105

1. Check for spark at cylinder No. 2 by performing spark test. See «SPARK TEST»(ref-133196-S06466806432002021900000) under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Cylinder No. 2 is the second cylinder back from timing chain end of engine and uses the ignition coil No. 2. If spark exists, go to next step. If spark does not exist, go to step 4.
2. Check for open and short in Blue and Black/Yellow wires and electrical connectors between ECM and ignition coil No. 2. See «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind glove box. see scheme 2 If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
3. Disconnect electrical connector at ignition coil No. 2. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 10 (Black/Yellow wire) at ECM electrical connector E8. (Scheme 99) This is the IGF terminal on ECM. Voltage should 4.5-5.5 volts. If voltage is within specification, replace ignition coil No. 2. If voltage is not within specification, replace ECM.
4. Check for open and short in Blue wire and electrical connectors between ECM and ignition coil No. 2. See «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind glove box. see scheme 2 If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
5. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Using voltmeter, check voltage between body ground and terminal No. 12 (Blue wire) at ECM electrical connector E8 while cranking engine. (Scheme 99) This is the IGT2 terminal on ECM. Voltage should be more than.1 volt and less than 4.5 volts. If voltage is not within specification, go to next step. If voltage is within specification, go to step 7.
6. Disconnect electrical connector at ignition coil No. 2. Using voltmeter, check voltage between body ground and terminal No. 12 (Blue wire) at ECM electrical connector E8 while cranking engine. (Scheme 99) Voltage should be more than.1 volt and less than 4.5 volts. If voltage is within specification, replace ignition coil No. 2. If voltage is not within specification, replace ECM.
7. Disconnect electrical connector at ignition coil No. 2. Using voltmeter, check voltage between body ground and terminal No. 1 (Black/Red wire) at electrical connector for ignition coil No. 2 with ignition switch in ON and START positions. (Scheme 105) Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, check power supply circuit between ignition switch and ignition coil No. 2. See «WIRING DIAGRAMS»(ref-133228) article.
8. Check for open in Brown wire and electrical connectors between ground and ignition coil No. 2. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, replace ignition coil No. 2. If wiring harness or electrical connector is defective, repair as necessary.

1. Check for spark at cylinder No. 3 by performing spark test. See «SPARK TEST»(ref-133196-S06466806432002021900000) under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Cylinder No. 3 is the third cylinder back from timing chain end of engine and uses the ignition coil No. 3. If spark exists, go to next step. If spark does not exist, go to step 4.
2. Check for open and short in Blue/Red and Black/Yellow wires and electrical connectors between ECM and ignition coil No. 3. See «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind glove box. see scheme 2 If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
3. Disconnect electrical connector at ignition coil No. 3. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 10 (Black/Yellow wire) at ECM electrical connector E8. (Scheme 99) This is the IGF terminal on ECM. Voltage should 4.5-5.5 volts. If voltage is within specification, replace ignition coil No. 3. If voltage is not within specification, replace ECM.
4. Check for open and short in Blue/Red wire and electrical connectors between ECM and ignition coil No. 3. See «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind glove box. see scheme 2 If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
5. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Using voltmeter, check voltage between body ground and terminal No. 13 (Blue/Red wire) at ECM electrical connector E8 while cranking engine. (Scheme 99) This is the IGT3 terminal on ECM. Voltage should be more than.1 volt and less than 4.5 volts. If voltage is not within specification, go to next step. If voltage is within specification, go to step 7.
6. Disconnect electrical connector at ignition coil No. 3. Using voltmeter, check voltage between body ground and terminal No. 13 (Blue/Red wire) at ECM electrical connector E8 while cranking engine. (Scheme 99) Voltage should be more than.1 volt and less than 4.5 volts. If voltage is within specification, replace ignition coil No. 3. If voltage is not within specification, replace ECM.
7. Disconnect electrical connector at ignition coil No. 3. Using voltmeter, check voltage between body ground and terminal No. 1 (Black/Red wire) at electrical connector for ignition coil No. 3 with ignition switch in ON and START positions. (Scheme 105) Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, check power supply circuit between ignition switch and ignition coil No. 3. See «WIRING DIAGRAMS»(ref-133228) article.
8. Check for open in Brown wire and electrical connectors between ground and ignition coil No. 3. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, replace ignition coil No. 3. If wiring harness or electrical connector is defective, repair as necessary.

1. Check for spark at cylinder No. 4 by performing spark test. See «SPARK TEST»(ref-133196-S06466806432002021900000) under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Cylinder No. 4 is the fourth cylinder back from timing chain end of engine and uses the ignition coil No. 4. If spark exists, go to next step. If spark does not exist, go to step 4.
2. Check for open and short in Blue/Yellow and Black/Yellow wires and electrical connectors between ECM and ignition coil No. 4. See «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind glove box. see scheme 2 If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
3. Disconnect electrical connector at ignition coil No. 4. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 10 (Black/Yellow wire) at ECM electrical connector E8. (Scheme 99) This is the IGF terminal on ECM. Voltage should 4.5-5.5 volts. If voltage is within specification, replace ignition coil No. 4. If voltage is not within specification, replace ECM.
4. Check for open and short in Blue/Yellow wire and electrical connectors between ECM and ignition coil No. 4. See «WIRING DIAGRAMS»(ref-133228) article. ECM is located behind glove box. see scheme 2 If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
5. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Using voltmeter, check voltage between body ground and terminal No. 14 (Blue/Yellow wire) at ECM electrical connector E8 while cranking engine. (Scheme 99) This is the IGT4 terminal on ECM. Voltage should be more than.1 volt and less than 4.5 volts. If voltage is not within specification, go to next step. If voltage is within specification, go to step 7.
6. Disconnect electrical connector at ignition coil No. 4. Using voltmeter, check voltage between body ground and terminal No. 14 (Blue/Yellow wire) at ECM electrical connector E8 while cranking engine. (Scheme 99) Voltage should be more than.1 volt and less than 4.5 volts. If voltage is within specification, replace ignition coil No. 4. If voltage is not within specification, replace ECM.
7. Disconnect electrical connector at ignition coil No. 4. Using voltmeter, check voltage between body ground and terminal No. 1 (Black/Red wire) at electrical connector for ignition coil No. 4 with ignition switch in ON and START positions. (Scheme 105) Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, check power supply circuit between ignition switch and ignition coil No. 4. See «WIRING DIAGRAMS»(ref-133228) article.
8. Check for open in Brown wire and electrical connectors between ground and ignition coil No. 4. See «WIRING DIAGRAMS»(ref-133228) article. If wiring harness and electrical connectors are okay, replace ignition coil No. 4. If wiring harness or electrical connector is defective, repair as necessary.

1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step 6.
2. Check stoplight operation. If stoplights operate properly, go to next step. If stoplights do not operate properly, repair as necessary and retest system. See EXTERIOR LIGHTS article in ACCESSORIES & EQUIPMENT.
3. Connect Toyota hand-held tester to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. see scheme 1 Turn ignition on and then turn hand-held tester on.
4. Monitor STP signal on hand-held tester while depressing and releasing brake pedal. STP signal should indicate ON with brake pedal depressed and OFF with brake pedal released. If STP signal is not as specified, go to next step. If STP signal is as specified, problem is intermittent. Check for defective connections or intermittent problem in wiring harness between stoplight switch and ECM, and for intermittent problem with stoplight switch. ECM is located behind glove box. see scheme 2 See «WIRING DIAGRAMS»(ref-133228) article. Stoplight switch is located near top of brake pedal.
5. Check wiring harness and electrical connectors between stoplight switch and ECM. See «WIRING DIAGRAMS»(ref-133228) article. Stoplight switch is located near top of brake pedal. ECM is located behind glove box. see scheme 2 If wiring harness and electrical connectors are okay, replace ECM. If wiring harness or electrical connectors are defective, repair as necessary.
6. Check stoplight operation. If stoplights operate properly, go to next step. If stoplights do not operate properly, repair as necessary and retest system. See appropriate EXTERIOR LIGHTS article in ACCESSORIES & EQUIPMENT.
7. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2
8. Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 15 (Green/White wire) at ECM electrical connector E5 while depressing and releasing brake pedal. (Scheme 99) This is the STP terminal on ECM.
9. With brake pedal depressed, voltage should be 7.5-14.0 volts. With brake pedal released, voltage should be less than 1.5 volts. If voltage is not within specification, go to next step. If voltage is within specification, problem is intermittent. Check for defective connections or intermittent problem in wiring harness and electrical connectors between stoplight switch and ECM, and for intermittent problem with stoplight switch. See «WIRING DIAGRAMS»(ref-133228) article. Stoplight switch is located near top of brake pedal.
10. Check wiring harness and electrical connectors between stoplight switch and ECM. See «WIRING DIAGRAMS»(ref-133228) article. Stoplight switch is located near top of brake pedal. If wiring harness and electrical connectors are okay, replace ECM. If wiring harness or electrical connectors are defective, repair as necessary.

1. Remove glove box for access to ECM with electrical connectors still installed on ECM. see scheme 2 Using voltmeter, check voltage between body ground and terminal No. 1 (Black/Yellow wire) at ECM electrical connector E5. (Scheme 99) This is the BATT terminal on ECM. Voltage should be 9-14 volts. If voltage is not within specification, go to next step. If voltage is within specification, replace ECM.
2. Remove EFI fuse (20-amp) from fuse/relay box at driver's side front corner of engine compartment. 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 appropriate POWER DISTRIBUTION article in WIRING DIAGRAMS. 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.