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Engine Control System Self-Diagnostics: Diagnosis Toyota Echo I

Testing & Diagnostics 12 illustrations ~12516 words

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 with engine off. MIL should come on and remain on. MIL is displayed as an engine icon located above the fuel gauge on instrument cluster on instrument panel. If MIL comes on, go to next step. If MIL does not come on, check bulb circuit on instrument cluster and wiring circuit between MIL and ECM. See «WIRING DIAGRAMS»(ref-133228) article. See «ENGINE CONTROL MODULE LOCATION»(ref-133206-S28092713052002021900000) .
  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-133206-S26281449812002021900000) .

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-133206-S18885233452002021900000) .
  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-133206-S08566217272002021900000) .
  4. Visual Inspection Inspect all electrical connectors and wiring for suspected circuit or component. Ensure all electrical connections are clean and tight.
  5. Confirm Symptoms & Diagnostic Trouble Codes Perform road test. Determine if original symptoms still exist. Using scan tool or Toyota hand-held tester, retrieve DTCs from ECM. See «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-133206-S18885233452002021900000) .
  6. Diagnose & Repair Diagnostic Trouble Codes Perform appropriate DTC test listed under «DIAGNOSTIC TESTS»(ref-133206-S07296211652002021900000) as necessary. For DTC descriptions, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-133206-S38407707592002021900000) 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-133206-S08566217272002021900000) . Perform road test. Ensure no DTCs exist and all symptoms and/or complaints have been repaired.

RETRIEVING DIAGNOSTIC TROUBLE CODES

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

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

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

NORMAL Mode Diagnostic Trouble Code Retrieval

  1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on with engine off. Turn hand-held tester or scan tool on. Using hand-held tester or scan tool manufacturer's instructions, check for DTCs and freeze frame data.
  2. If hand-held tester or scan tool does not display UNABLE TO CONNECT TO VEHICLE, go to next step. If hand-held tester or scan tool displays UNABLE TO CONNECT TO VEHICLE, check DLC No. 3. See «DATA LINK CONNECTOR NO. 3 INSPECTION»(ref-133206-S22845614122002021900000) under SCAN TOOL PROBLEMS.
  3. Record any DTCs and freeze frame data displayed for system diagnosis. If driveability problem exist and no DTCs are present, go to «TROUBLE SHOOTING - NO CODES»(ref-133220) article for diagnosis by symptom.
  4. If any DTCs are present, perform appropriate DTC test under «DIAGNOSTIC TESTS»(ref-133206-S07296211652002021900000). For DTC descriptions, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-133206-S38407707592002021900000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. For more information on freeze frame data, see «FREEZE FRAME DATA»(ref-133206-S39812216982002021900000). For information on two-trip detection logic codes, see «TWO-TRIP DETECTION LOGIC»(ref-133206-S13103334192002021900000).
  5. After repairs for DTC have been completed, DTC must be cleared from ECM. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-133206-S08566217272002021900000). Road test vehicle to ensure all symptoms and/or complaints have been repaired.

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

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

  1. Ensure vehicle battery is fully charged. Apply parking brake. Place transaxle in Neutral (M/T) or Park (A/T). 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. 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 and allow engine to idle. If no DTCs are present, MIL will turn off. Try to simulate conditions of driveability complaint described by customer.
  3. Record any DTCs and freeze frame data displayed for system diagnosis. If driveability problem exist and no DTCs are present, go to «TROUBLE SHOOTING - NO CODES»(ref-133220) article for diagnosis by symptom.
  4. If any DTCs are present, perform appropriate DTC test under «DIAGNOSTIC TESTS»(ref-133206-S07296211652002021900000). For DTC description, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-133206-S38407707592002021900000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. For information on freeze frame data, see «FREEZE FRAME DATA»(ref-133206-S39812216982002021900000). For information on two-trip detection logic codes, see «TWO-TRIP DETECTION LOGIC»(ref-133206-S13103334192002021900000).
  5. After repairs for DTC have been completed, DTC must be cleared from ECM. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-133206-S08566217272002021900000). 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 (15-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, a test drive confirmation test can be performed to verify repairs are made and that DTC does not reset. Test drive confirmation test will duplicate conditions required to set specified DTCs.
  2. Test drive confirmation test lists the procedure to be performed to check that DTC does not reset. Test drive confirmation tests apply only to specific DTCs. Test drive confirmation test will be included within proper DTC test under «DIAGNOSTIC TESTS»(ref-133206-S07296211652002021900000) .

DATA LINK CONNECTOR NO. 3 INSPECTION

  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 DLC No. 3 for loose or damaged terminals. Ensure DLC No. 3 terminals are in correct position in connector. 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»(ref-133228). If connector and terminals are okay, go to next step. If connector or terminals are defective, repair as necessary.
  3. Check voltage and resistance between ground and specified terminal on DLC No. 3. See «DATA LINK CONNECTOR NO. 3 VOLTAGE & RESISTANCE SPECIFICATIONS»(ref-133206-S03685537512002021900000) table. (Scheme 53) If voltage or resistance readings are not within specification, check wiring circuit. See «WIRING DIAGRAMS»(ref-133228) article.
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).
(1)Pulse generation should exist during information transmission from Engine Control Module (ECM).

DATA LINK CONNECTOR NO. 3 VOLTAGE & RESISTANCE SPECIFICATIONS

Scheme 53

Scheme 53
Scheme 53

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DTC (1)Description
P0100 (2)Mass Airflow Meter Circuit
P0101Mass Airflow Meter Circuit Range/Performance
P0110 (2)Intake Air Temperature Sensor Circuit
P0115 (2)Engine Coolant Temperature Sensor Circuit
P0116Engine Coolant Temperature Sensor Circuit Range/Performance
P0120 (2)Throttle Position Sensor Circuit
P0121Throttle Position Sensor Circuit Range/Performance
P0125Insufficient Coolant Temperature For Closed Loop Fuel Control
P0130Heated Oxygen Sensor No. 1 Circuit
P0133Heated Oxygen Sensor No. 1 Circuit Slow Response
P0135 (2)Heated Oxygen Sensor No. 1 Heater Circuit
P0136Heated Oxygen Sensor No. 2 Circuit
P0141 (2)Heated Oxygen Sensor No. 2 Heater Circuit
P0171System Too Lean
P0172System Too Rich
P0300Random Misfire Detected
P0301Cylinder No. 1 Misfire Detected
P0302Cylinder No. 2 Misfire Detected
P0303Cylinder No. 3 Misfire Detected
P0304Cylinder No. 4 Misfire Detected
P0325 (2)Knock Sensor Circuit
P0335Crankshaft Position Sensor Circuit
P0340Camshaft Position Sensor Circuit
P0420Catalyst System Efficiency Below Threshold
P0440Evaporative Emission Control System
P0441Incorrect EVAP Purge Flow
P0446EVAP Vent Control Circuit
P0450EVAP Pressure Sensor Circuit
P0451EVAP Pressure Sensor Range/Performance
P0500Vehicle Speed Sensor Circuit
P0505Idle Air Control System Circuit
P0550Power Steering Oil Pressure Sensor Circuit Malfunction
P0710 (3)Transmission Fluid Temperature Sensor Malfunction
P0750 (3)Shift Solenoid Valve SL1 Malfunction
P0753 (3)Shift Solenoid Valve SL1 Electrical Malfunction
P0755 (3)Shift Solenoid Valve SL2 Malfunction
P0758 (3)Shift Solenoid Valve SL2 Electrical Malfunction
P0770 (3)Lock-Up Solenoid Malfunction
P0773 (3)Lock-Up Solenoid Circuit Electrical Malfunction
P1300 (2)Ignitor No. 1 Circuit
P1305 (2)Ignitor No. 2 Circuit
P1310 (2)Ignitor No. 3 Circuit
P1315 (2)Ignitor No. 4 Circuit
P1345VVT/Camshaft Position Sensor Circuit Malfunction
P1346Variable Valve Timing Sensor Circuit Range/Performance
P1349Variable Valve Timing System Malfunction
P1520 (4)Stoplight Switch Signal Circuit
P1600ECM BATT Circuit
P1656Oil Control Valve Malfunction
P1725 (3)Input Turbine Speed Sensor Circuit Malfunction
P1760 (3)Shift Solenoid Valve SLT Malfunction
P1790 (3)ST Solenoid Valve Circuit Malfunction
P1780 (4)Park/Neutral Position Switch Circuit
(1) Some DTCs are two-trip detection logic DTCs. For more information, see TWO-TRIP DETECTION LOGIC under SELF-DIAGNOSTIC SYSTEM. (2) If this DTC is set, Engine Control Module (ECM) will enter fail-safe mode. (3) DTC applies only to models with electronically controlled automatic transaxle. For testing procedures, see appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS. (4) DTC applies only to A/T models.
(1)Some DTCs are two-trip detection logic DTCs. For more information, see TWO-TRIP DETECTION LOGIC under SELF-DIAGNOSTIC SYSTEM.
(2)If this DTC is set, Engine Control Module (ECM) will enter fail-safe mode.
(3)DTC applies only to models with electronically controlled automatic transaxle. For testing procedures, see appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS.
(4)DTC applies only to A/T models.

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TESTS

Note. Before performing any diagnostic test, see SELF-DIAGNOSTIC SYSTEM for diagnostic system functions and system diagnostic procedures. Also check for any related Technical Service Bulletins (TSBs). For component location, see appropriate illustration in THEORY & OPERATION article.

Note. When performing diagnostic tests, it may be necessary to identify Engine Control Module (ECM) harness connector terminals referenced in testing. (Scheme 54)

Scheme 54

Scheme 54: DIAGNOSTIC TESTS
Scheme 54: DIAGNOSTIC TESTS

Diagnosis & Repair

  1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on and then turn hand-held tester or scan tool on. Start engine and allow engine to idle. Using hand-held tester or scan tool, monitor MAF meter air flow rate. If MAF meter air flow rate is 0.0 gm/sec., go to next step. If MAF meter air flow rate is 271 gm/sec. or more, go to step 5.
  2. Turn ignition off. Disconnect MAF meter harness connector. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black/Yellow wire) at MAF meter harness connector. (Scheme 55) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, repair open in Black/Yellow wire between EFI relay and MAF meter. See «WIRING DIAGRAMS»(ref-133228) article.
  3. Turn ignition off. Connect MAF meter harness connector. Access ECM behind glove box. see scheme 2 Ensure shift lever is in Neutral or Park. Ensure A/C switch is OFF. Start engine and allow engine to idle. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 2 (Pink wire) at ECM harness connector E6. (Scheme 54) If voltage is not 1.1-1.5 volts, go to next step. If voltage is 1.1-1.5 volts, replace ECM.
  4. Check for open or short in Pink wire between MAF meter and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace MAF meter.
  5. Turn ignition off. Access ECM behind glove box. see scheme 2 Using DVOM, backprobe ECM harness connector and measure resistance between ground and terminal No. 10 (Violet wire) at ECM harness connector E6. (Scheme 54) If resistance is one ohm or less, go to next step. If resistance is greater than one ohm, replace ECM.
  6. Check for open in Violet wire between MAF meter and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace MAF meter.

Scheme 55

Scheme 55
Scheme 55

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

  1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on and then turn hand-held tester or scan tool on. Using hand-held tester or scan tool, monitor IAT sensor temperature. If displayed intake air temperature is -40°F (-40°C), go to next step. If displayed intake air temperature is 284°F (140°C) or more, go to step 4. If displayed intake air temperature is same as intake air temperature, problem is intermittent. Check component and ECM connections.
  2. Turn ignition off. Disconnect MAF meter harness connector. Connect a jumper wire between terminals No. 4 (Yellow/Black wire) and No. 5 (Brown wire) at MAF meter harness connector. (Scheme 55) Turn ignition on. Using hand-held tester or scan tool, monitor IAT sensor temperature. If displayed intake air temperature is less than 284°F (140°C), go to next step. If displayed intake air temperature is 284°F (140°C) or more, replace MAF meter.
  3. Turn ignition off. Remove jumper wire. Access ECM behind glove box. see scheme 2 Connect a jumper wire by backprobing between terminals No. 3 (Yellow/Black wire) and No. 9 (Brown wire) at ECM harness connector E6. (Scheme 54) Turn ignition on. Using hand-held tester or scan tool, read intake air temperature for IAT sensor. Displayed intake air temperature should be 284°F (140°C) or more. If displayed intake air temperature is as specified, repair open in wiring between MAF meter and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If displayed intake air temperature is not as specified, replace ECM.
  4. Turn ignition off. Disconnect MAF meter harness connector. Turn ignition on. Using hand-held tester or scan tool, read intake air temperature for IAT sensor. If displayed intake air temperature is not -40°F (-40°C), go to next step. If displayed intake air temperature is -40°F (-40°C), replace MAF meter.
  5. Turn ignition off. Access ECM behind glove box. see scheme 2 Disconnect ECM harness connector E6. (Scheme 54) Turn ignition on. Using hand-held tester or scan tool, read intake air temperature for IAT sensor. If displayed intake air temperature is -40°F (-40°C), repair short in wiring between MAF meter and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If displayed intake air temperature is not -40°F (-40°C), replace ECM.
  1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on and then turn hand-held tester or scan tool on. Using hand-held tester or scan tool, monitor ECT sensor temperature. If displayed temperature is -40°F (-40°C), go to next step. If displayed temperature is 284°F (140°C) or more, go to step 4. If displayed temperature is same as actual coolant temperature, problem is intermittent. Check component and ECM connections.
  2. Turn ignition off. Disconnect ECT sensor harness connector. Connect a jumper wire between ECT sensor harness connector terminals. Turn ignition on. Using hand-held tester or scan tool, monitor ECT sensor temperature. If displayed temperature is less than 284°F (140°C), go to next step. If displayed temperature is 284°F (140°C) or more, replace ECT sensor.
  3. Turn ignition off. Remove jumper wire. Access ECM behind glove box. see scheme 2 Connect a jumper wire by backprobing between terminals No. 4 (Red/Blue wire) and No. 9 (Brown wire) at ECM harness connector E6. (Scheme 54) Using hand-held tester or scan tool, monitor ECT sensor temperature. Displayed temperature should be 284°F (140°C) or more. If displayed temperature is as specified, repair open in wiring between ECT sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If displayed temperature is not as specified, replace ECM.
  4. Turn ignition off. Disconnect ECT sensor harness connector. Turn ignition on. Using hand-held tester or scan tool, monitor ECT sensor temperature. If displayed temperature is not -40°F (-40°C), go to next step. If displayed temperature is -40°F (-40°C), replace ECT sensor.
  5. Turn ignition off. Access ECM behind glove box. see scheme 2 Disconnect ECM harness connector E6. (Scheme 54) Turn ignition on. Using hand-held tester or scan tool, monitor ECT sensor temperature. If displayed temperature is -40°F (-40°C), repair short in wiring between ECT sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If displayed temperature is not -40°F (-40°C), replace ECM.
  1. Using Toyota hand-held tester or scan tool, 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. If problem exists, replace thermostat as necessary and retest system. If problem does not exist, replace ECT sensor.
  1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on and then turn hand-held tester or scan tool on. Using hand-held tester or scan tool, 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 70 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 component and ECM connections.
  2. Turn ignition off. Disconnect TP sensor harness connector. Turn ignition on. Using DVOM, measure voltage between ground and terminal No. 1 (Red/White wire) at TP sensor harness connector. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, go to step 5.
  3. Check TP sensor. See «ENGINE SENSORS & SWITCHES»(ref-133221-S30584064082002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem does not exist, go to next step. If problem exists, replace TP sensor.
  4. Turn ignition off. Connect TP sensor harness connector. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 9 (Brown wire) and No. 11 (Yellow/Red wire) at ECM harness connector E6. (Scheme 54) Voltage should be.3-1.0 volt with throttle fully closed, and 3.2-4.9 volts with throttle fully open. If voltage is as specified, replace ECM. If voltage is not as specified, repair open or short in wiring between TP sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article.
  5. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 1 (Red/White wire) and No. 9 (Brown wire) at ECM harness connector E6. (Scheme 54) Voltage should be 4.5-5.5 volts. If voltage is as specified, repair open in Red/White wire between TP sensor and ECM. If voltage is not as specified, replace ECM.

Circuit Description

Throttle Position (TP) sensor is a variable resistor which monitors throttle opening. ECM determines vehicle driving condition and adjusts air/fuel mixture accordingly. DTC is set after vehicle speed has exceeded 19 MPH once and TP sensor output voltage is out of range while vehicle speed is 0-19 MPH. Possible causes are

  1. Defective Throttle Position (TP) sensor.
  2. Defective ECM.

Diagnostic Aids

Using Toyota 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. 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 P0125 exists, go to next step.
  2. With hand-held tester or scan tool still connected to DLC No. 3, start engine and warm engine to normal operating temperature. Using hand-held tester or scan tool, monitor heated oxygen sensor No. 1. Snap accelerate engine to about 4000 RPM 3 times. Heated oxygen sensor No. 1 should indicate a rich signal (.45 volt or more) at least once. If heated oxygen sensor No. 1 does not display a rich signal at least once, go to next step. If a rich signal is indicated for heated oxygen sensor No. 1 at least once, go to step 9 .
  3. Check for open or short in wiring between heated oxygen sensor No. 1 and ECM. Heated oxygen sensor No. 1 is located on exhaust pipe in front of catalytic converter. If problem does not exist, go to next step. If problem exists, repair wiring as necessary. See «WIRING DIAGRAMS»(ref-133228) article.
  4. Using hand-held tester or scan tool, check if a misfire has occurred by monitoring DTCs and DATA LIST. If misfire has not occurred, go to next step. If misfire has occurred, perform «DTC P0300: RANDOM MISFIRE DETECTED»(ref-133206-S13348666222002021900000) .
  5. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem does not exist, go to next step. If problem exists, repair as necessary.
  6. Check fuel pressure. See «FUEL SYSTEMS»(ref-133196-S02740135242002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm 2 ) at idle, and should be 21 psi (1.5 kg/cm 2 ) or more for 5 minutes after engine has stopped. If problem does not exist, go to next step. If fuel pressure is not as specified, repair as necessary.
  7. Check operation of fuel injectors. See «FUEL SYSTEMS»(ref-133221-S24954902022002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be .16-.20 oz. (47-58 cc) every 15 seconds and difference in volume between each fuel injector should be less than .03 oz.. (10 cc). Fuel injector should not leak more than one drop every 12 minutes. If problem does not exist, go to next step. If problem exists, repair as necessary.
  8. Check exhaust system for leaks. If problem exists, repair as necessary. If problem does not exist, replace defective heated oxygen sensor No. 1.
  9. Using Toyota hand-held tester or scan tool, clear DTCs from ECM. Perform test drive confirmation, then go to next step. See «TEST DRIVE CONFIRMATION»(ref-133206-S28444815112002021900000) under DTC P0130: HEATED OXYGEN SENSOR NO. 1 CIRCUIT.
  10. Recheck for DTCs. If DTC P0125 is not displayed again, go to next step. If DTC P0125 is displayed again, replace ECM.
  11. Vehicle either ran out of fuel or problem is intermittent. Check component and ECM connections.
  1. If using OBD-II scan tool, go to step 3. If using Toyota hand-held tester, connect hand-held tester to Data Link Connector (DLC) No. 3. see scheme 1 Switch hand-held tester to CHECK mode and go to next step.
  2. Start engine and warm engine to normal operating temperature with all accessories off. Drive vehicle at 24 MPH or more for 1-3 minutes. Stop vehicle and allow to idle for one minute. Repeat driving and idling part of test 3 times. 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.
  3. Start engine and warm engine to normal operating temperature. Drive vehicle at 24 MPH for 1-3 minutes. Stop vehicle and allow to idle for one minute. Repeat driving and idling part of test 3 times. Go to next step.
  4. Turn ignition off. Repeat step 3. 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 other DTCs exist, diagnose and repair those DTCs first and retest. If only DTC P0130 exists, go to next step.
  2. With hand-held tester or scan tool connected to DLC No. 3, start engine and increase engine speed to 2500 RPM for approximately 90 seconds. Let engine idle. Using hand-held tester or scan tool, monitor heated oxygen senor No. 1 output voltage. Output voltage should alternate repeatedly between less than .4 volt and more than .55 volt. If output voltage is not as specified, go to next step. If output voltage is as specified, go to step 7 .
  3. Check for open or short in wiring between ECM and heated oxygen sensor No. 1. Heated oxygen sensor No. 1 is located on exhaust pipe in front of catalytic converter. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
  4. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, go to next step.
  5. Check fuel pressure. See «FUEL SYSTEMS»(ref-133196-S02740135242002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm 2 ) at idle, and should be 21 psi (1.5 kg/cm 2 ) or more for 5 minutes after engine has stopped. If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, repair as necessary.
  6. Check operation of fuel injectors. See «FUEL SYSTEMS»(ref-133221-S24954902022002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be .16-.20 oz. (47-58 cc) every 15 seconds and difference in volume between each fuel injector should be less than .03 oz.. (10 cc). Fuel injector should not leak more than one drop every 12 minutes. If problem exists, repair as necessary. If problem does not exist, replace heated oxygen sensor No. 1.
  7. Using hand-held tester or scan tool, clear DTCs from ECM. Perform test drive confirmation, then go to next step. See «TEST DRIVE CONFIRMATION»(ref-133206-S28444815112002021900000) .
  8. Recheck for DTCs. If DTC P0130 is displayed again, replace ECM. If DTC P0130 is not displayed again, problem is intermittent. Check component and ECM connections.
  1. Using Toyota hand-held tester or scan tool, check for any other DTCs. If only DTC P0133 exists, go to next step. If other DTCs exist, diagnose and repair those DTCs first and retest.
  2. With hand-held tester or scan tool still connected to DLC No. 3, start engine and increase engine speed to 2500 RPM for approximately 90 seconds. Let engine idle. Using hand-held tester or scan tool, monitor heated oxygen sensor No. 1 output voltage. Output voltage should alternate repeatedly between less than .4 volt and more than .55 volt. If output voltage is not as specified, go to next step. If output voltage is as specified, go to step 7 .
  3. Check for open or short in wiring between ECM and heated oxygen sensor No. 1. Heated oxygen sensor No. 1 is located on exhaust pipe in front of catalytic converter. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
  4. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem does not exist, go to next step. If problem exists, repair as necessary.
  5. Check fuel pressure. See «FUEL SYSTEMS»(ref-133196-S02740135242002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm 2 ) at idle, and should be 21 psi (1.5 kg/cm 2 ) or more for 5 minutes after engine has stopped. If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, repair as necessary.
  6. Check operation of fuel injectors. See «FUEL SYSTEMS»(ref-133221-S24954902022002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be .16-.20 oz. (47-58 cc) every 15 seconds and difference in volume between each fuel injector should be less than .03 oz.. (10 cc). Fuel injector should not leak more than one drop every 12 minutes. If problem exists, repair as necessary. If problem does not exist, replace heated oxygen sensor No. 1.
  7. Using hand-held tester or scan tool, clear DTCs from ECM. Perform test drive confirmation, then go to next step. See «TEST DRIVE CONFIRMATION»(ref-133206-S28444815112002021900000) under DTC P0130: HEATED OXYGEN SENSOR NO. 1 CIRCUIT.
  8. Recheck for DTCs. If DTC P0133 is displayed again, replace ECM. If DTC P0133 is not displayed again, problem is intermittent. Check component and ECM connections.
  1. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 8 (Orange wire) at ECM harness connector E6. (Scheme 54) Voltage should be 9-14 volts. If voltage is not as specified, go to next step. If voltage is as specified, replace ECM.
  2. Disconnect heated oxygen sensor No. 1 harness connector. Heated oxygen sensor No. 1 is located on exhaust pipe in front of catalytic converter. Measure resistance between terminals B+ (Blue wire) and HT (Orange wire) at heated oxygen sensor No. 1 (component side). (Scheme 56) Resistance should be 11-16 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace heated oxygen sensor No. 1.
  3. Repair wiring between ECM and heated oxygen sensor No. 1, or between heated oxygen sensor No. 1 and EFI relay. See «WIRING DIAGRAMS»(ref-133228) article.

Scheme 56

Scheme 56
Scheme 56
  1. Using Toyota hand-held tester or scan tool, check for any other DTCs. If only DTC P0136 exists, go to next step. If other DTCs exist, diagnose and repair those DTCs first and retest.
  2. Check for open or short in wiring between ECM and heated oxygen sensor No. 2. Heated oxygen sensor No. 2 is located on exhaust pipe in behind catalytic converter. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
  3. With hand-held tester or scan tool still connected to DLC No. 3, start engine and warm engine to normal operating temperature. Monitor heated oxygen sensor No. 2 output voltage. Snap accelerate engine to about 4000 RPM 3 times. Output voltage should fluctuate from less than .4 volt to .5 volt or more. If output voltage is as specified, problem is intermittent. Check component and ECM connections. If output voltage is not as specified, replace heated oxygen sensor No. 2.
  1. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 16 (White wire) at ECM harness connector E6. (Scheme 54) Voltage should be 9-14 volts. If voltage is not as specified, go to next step. If voltage is as specified, replace ECM.
  2. Disconnect heated oxygen sensor No. 2 harness connector. Passenger's seat may need to be remove to access heated oxygen sensor No. 2 harness connector. Measure resistance between terminals B+ (Black/Yellow wire) and HT (White wire) at heated oxygen sensor No. 2 (component side). (Scheme 57) Resistance should be 11-16 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace heated oxygen sensor No. 2.
  3. Repair wiring between ECM and heated oxygen sensor No. 2, or between heated oxygen sensor No. 2 and EFI relay. See «WIRING DIAGRAMS»(ref-133228) article.

Scheme 57

Scheme 57
Scheme 57
  1. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, go to next step.
  2. Check operation of fuel injectors. See «FUEL SYSTEMS»(ref-133221-S24954902022002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be.16-.20 oz. (47-58 cc) every 15 seconds and difference in volume between each fuel injector should be less than.03 oz.. (10 cc). Fuel injector should not leak more than one drop every 12 minutes. If problem does not exist, go to next step. If problem exists, repair as necessary.
  3. Check Mass Airflow (MAF) meter and Engine Coolant Temperature (ECT) sensor. MAF meter may also be referred to as airflow meter. See «ENGINE SENSORS & SWITCHES»(ref-133221-S30584064082002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem does not exist, go to next step. If problem exists, replace appropriate component.
  4. Check ignition system by performing spark test. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If problem does not exist, go to next step. If problem exists, repair as necessary.
  5. Check fuel pressure. See «FUEL SYSTEMS»(ref-133196-S02740135242002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm 2 ) at idle, and should be 21 psi (1.5 kg/cm 2 ) or more for 5 minutes after engine has stopped. If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, repair as necessary.
  6. Check exhaust system for leaks. If problem does not exist, go to next step. If problem exists, repair as necessary.
  7. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Start engine and increase engine speed to 2500 RPM for approximately 90 seconds. Let engine idle. Using hand-held tester or scan tool, monitor heated oxygen sensor No. 1 output voltage. Output voltage should alternate repeatedly from less than.4 volt to more than.5 volt. If output voltage is not as specified, go to next step. If output voltage is as specified, go to step 9.
  8. Check for open or short in wiring between ECM and heated oxygen sensor No. 1. Heated oxygen sensor No. 1 is located on exhaust pipe in front of catalytic converter. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace heated oxygen sensor No. 1.
  9. Using Toyota hand-held tester or scan tool, clear DTCs from ECM. Perform test drive confirmation, then go to next step. See «TEST DRIVE CONFIRMATION»(ref-133206-S28444815112002021900000) under DTC P0130: HEATED OXYGEN SENSOR NO. 1 CIRCUIT.
  10. Recheck for DTCs. If neither DTC P0171 nor DTC P0172 is displayed again, go to next step. If DTC P0171 and/or DTC P0172 are displayed again, replace ECM.
  11. Vehicle either ran out of fuel or problem is intermittent. Check component and ECM connections.
  1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Record any DTCs and freeze frame data. Switch hand-held tester to CHECK mode (Toyota hand-held tester only). Drive vehicle several times with engine speed, load and its surrounding range shown with ENGINE SPD, CALC LOAD in freeze frame data or MISFIRE RPM and MISFIRE LOAD in scan tool data list.
  2. Drive vehicle at specified engine speeds. See «DRIVING PATTERN»(ref-133206-S18023935312002021900000) table. Turn ignition off after symptom is simulated the first time, then repeat test drive again (OBD-II scan tool only). If a misfire is detected, a DTC will set and misfire will be indicated in freeze frame data. Turn ignition off and wait a minimum of 5 seconds. DRIVING PATTERN RPM (1) Minutes Idling 3 1/2 1000 3 2000 1 1/2 3000 1 (1) Minimum specification is given.
  1. Check vacuum hoses for leaks, blockage and proper routing. See appropriate illustration in VACUUM DIAGRAMS article. Also, check wiring and connectors for damage or poor connections. If problem does not exist, go to next step. If problem exists, repair as necessary and perform «TEST DRIVE CONFIRMATION»(ref-133206-S31633469152002021900000).
  2. Check ignition system by performing spark test. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If problem does not exist, go to next step. If problem exists, repair as necessary.
  3. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM connector and measure voltage between ground and fuel injector driver terminal for misfiring cylinder at ECM harness connector E7. See «IDENTIFYING ECM FUEL INJECTOR DRIVER TERMINALS»(ref-133206-S14410613772002021900000) table. (Scheme 54) If voltage is not 9-14 volts at each terminal, go to next step. If voltage is 9-14 volts at each terminal, go to step 6. IDENTIFYING ECM FUEL INJECTOR DRIVER TERMINALS Fuel Injector No. (1) Terminal No. Wire Color 1 12 Black/Orange 2 11 Black/Yellow 3 25 Black/White 4 24 Black/Blue (1) Terminals are located at ECM harness connector E7. (Scheme 54)
  4. Disconnect fuel injector harness connector at misfiring cylinder. Measure resistance between fuel injector terminals (component side). Resistance should be 13.4-14.2 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace fuel injector.
  5. Check for open or short in wiring between ECM and fuel injector. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair as necessary. If problem does not exist, repair open or short in fuel injector power source circuit. See «WIRING DIAGRAMS»(ref-133228) article.
  6. Check fuel pressure. See «FUEL SYSTEMS»(ref-133196-S02740135242002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm 2 ) at idle, and should be 21 psi (1.5 kg/cm 2 ) or more for 5 minutes after engine has stopped. If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, repair as necessary.
  7. Check operation of fuel injector on misfiring cylinder. See «FUEL SYSTEMS»(ref-133221-S24954902022002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be.16-.20 oz. (47-58 cc) every 15 seconds and difference in volume between each fuel injector should be less than.03 oz.. (10 cc). Fuel injector should not leak more than one drop every 12 minutes. If problem does not exist, go to next step. If problem exists, repair as necessary.
  8. Check Mass Airflow (MAF) meter and Engine Coolant Temperature (ECT) sensor. MAF meter may also be referred to as airflow meter. See «ENGINE SENSORS & SWITCHES»(ref-133221-S30584064082002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem does not exist, go to next step. If problem exists, replace appropriate component.
  9. Check engine compression on misfiring cylinder. See «BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER»(ref-133196) article. Check valve clearance on misfiring cylinder. See «ON-VEHICLE ADJUSTMENTS - 4-CYLINDER»(ref-133193) article. Check valve timing. See appropriate article in ENGINES. Repair as necessary.

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

  1. Access ECM behind glove box. see scheme 2 Disconnect ECM harness connector E6. (Scheme 54) Use DVOM, backprobe ECM harness connector and measure resistance between ground and terminal No. 13 (White wire) at ECM harness connector E6. Resistance should be one megohm or more. If resistance is not as specified, go to next step. If resistance is as specified, go to step 3.
  2. Disconnect knock sensor harness connector. Check continuity between knock sensor terminal and knock sensor housing. If continuity does not exist, go to next step. If continuity exists, replace knock sensor.
  3. Check for open or short in wiring between knock sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, substitute knock sensor with known-good knock sensor. Using Toyota hand-held tester or scan tool, clear DTCs from ECM. Recheck for DTCs. If DTC P0325 is still displayed, replace ECM. If DTC P0325 is no longer displayed, replace knock sensor.
  1. Disconnect CKP sensor harness connector. Measure resistance between CKP sensor terminals (component side). Resistance should be 985-1600 ohms with sensor temperature of 14-122°F (-10-50°C) and 1265-1890 ohms with sensor temperature of 122-212°F (50-100°C). If problem does not exist, go to next step. If problem exists, replace CKP sensor.
  2. Check for open or short in wiring between ECM and CKP sensor. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
  3. Remove and inspect CKP sensor. Also, inspect crankshaft timing pulley teeth. If problem exists, replace CKP sensor and/or crankshaft timing pulley as necessary. If problem does not exist, replace ECM.

Note. A sensor is considered to be cold when sensor coils are 14-122°F (-10-50°C). A sensor is considered to be hot when sensor coils are

  1. Disconnect CMP sensor harness connector. Measure resistance between CMP sensor terminals (component side). Resistance should be 1630-2740 ohms with sensor temperature of 14-122°F (-10-50°C) and 2065-3225 ohms with sensor temperature of 122-212°F (50-100°C). If resistance is as specified, go to next step. If resistance is not as specified, replace CMP sensor.
  2. Check for open or short in wiring between ECM and CMP sensor. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
  3. Remove and inspect CMP sensor. Also, inspect signal plate on intake camshaft. If problem exists, replace CMP sensor and/or signal plate as necessary. If problem does not exist, replace ECM.
  1. Using Toyota hand-held tester or scan tool, check for any other DTCs. If only DTC P0420 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 problem does not exist, go to next step. If problem exists, repair as necessary.
  3. Check heated oxygen sensor No. 1. See «DTC P0130: HEATED OXYGEN SENSOR NO. 1 CIRCUIT»(ref-133206-S08476041702002021900000) . If problem does not exist, go to next step. If problem exists, repair as necessary.
  4. Check heated oxygen sensor No. 2. See «DTC P0136: HEATED OXYGEN SENSOR NO. 2 CIRCUIT»(ref-133206-S20255791372002021900000) test. If problem exists, repair as necessary. If problem does not exist, replace catalytic converter.
  1. Check for cracks and deformations in fuel tank, charcoal canister and fuel tank filler pipe. Check for disconnected hoses and tubes around fuel tank and charcoal canister. If problem exists, repair as necessary. If problem does not exist, go to next step.
  2. Check fuel tank cap to ensure fuel tank cap is a Original Equipment Manufacturer (OEM) fuel tank cap. If fuel tank cap is an OEM fuel tank cap, go to next step. If fuel tank cap is not an OEM fuel tank cap, replace fuel tank cap with an OEM fuel tank cap.
  3. Ensure fuel tank cap is properly installed and tightened. If fuel tank cap is properly installed and tightened, go to next step. If fuel tank cap is not properly installed or tightened, reinstall and tighten as necessary.
  4. Check fuel tank cap for damage and damaged gasket. If fuel tank cap is not damaged and gasket is okay, go to next step. If fuel tank cap or gasket is damaged, replace fuel tank cap with an OEM fuel tank cap.
  5. Remove fuel tank cap. Visually inspect fuel tank filler pipe for damage. If problem does not exist, go to next step. If problem exists, replace fuel tank filler pipe as necessary.
  6. Check vapor pressure sensor connection at fuel tank. Check vacuum hoses to charcoal canister. Check hoses for correct installation, looseness and damage. If problem does not exist, go to next step. If problem exists, repair vacuum hoses as necessary.
  7. Check hoses and tube between fuel tank and charcoal canister for correct installation and damage. If problem does not exist, go to next step. If problem exists, repair as necessary.
  8. Check charcoal canister for damage. If problem does not exist, go to next step. If problem exists, repair or replace as necessary.
  9. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 1 (Red/White wire) and No. 9 (Brown wire) at ECM harness connector E6. (Scheme 54) Voltage should be 4.5-5.5 volts. If voltage is as specified, go to next step. If voltage is not as specified, replace ECM.
  10. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 9 (Brown wire) and No. 14 (Black wire) at ECM harness connector E6. Remove fuel tank cap. Turn ignition on. Voltage should be 3.0-3.6 volts. If voltage is not as specified, go to next step. If voltage is as specified, go to step 12.
  11. Check for an open or short in wiring between vapor pressure sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.
  12. Check fuel tank and fuel tank overfill valve for damage. If problem exists, repair or replace fuel tank or fuel tank overfill valve as necessary. If problem does not exist, no fault is indicated at this time. Probable cause of DTC to set was an incorrectly installed fuel tank cap.
  1. Check for cracks and deformations in fuel tank, charcoal canister and fuel tank filler pipe. Check for disconnected hoses and tubes around fuel tank and charcoal canister. If problem does not exist, go to next step. If problem exists, repair as necessary.
  2. Check fuel tank cap to ensure fuel tank cap is a Original Equipment Manufacturer (OEM) fuel tank cap. If fuel tank cap is an OEM fuel tank cap, go to next step. If fuel tank cap is not an OEM fuel tank cap, replace fuel tank cap with an OEM fuel tank cap.
  3. Ensure fuel tank cap is properly installed and tightened. If fuel tank cap is properly installed and tightened, go to next step. If fuel tank cap is not properly installed or tightened, reinstall and tighten as necessary.
  4. Check fuel tank cap for damage and damaged gasket. If fuel tank cap is not damaged and gasket is okay, go to next step. If fuel tank cap or gasket is damaged, replace fuel tank cap with an OEM fuel tank cap.
  5. Remove fuel tank cap. Visually inspect fuel tank filler pipe for damage. If problem exists, replace fuel tank filler pipe as necessary. If problem does not exist, go to next step.
  6. Check all EVAP system electrical component connections. If problem does not exist, go to next step. If problem exists, repair as necessary.
  7. Check vacuum hoses between canister closed valve VSV and charcoal canister, between charcoal canister and fuel tank overfill check valve, between overfill check valve and fuel tank filler pipe, and between fuel tank filler pipe and fuel tank. If problem does not exist, go to next step. If problem exists, repair vacuum hoses as necessary.
  8. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 1 (Red/White wire) and No. 9 (Brown wire) at ECM harness connector E6. (Scheme 54) Voltage should be 4.5-5.5 volts. If voltage is as specified, go to next step. If voltage is not as specified, replace ECM.
  9. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 9 (Brown wire) and No. 14 (Black wire) at ECM harness connector E6. Remove fuel tank cap. Turn ignition on. Voltage should be 3.0-3.6 volts. If voltage is not as specified, go to next step. If voltage is as specified, go to step 11.
  10. Check for an open or short in wiring between vapor pressure sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.
  11. Disconnect EVAP VSV vacuum hoses. Turn ignition on. Access ECM behind glove box. see scheme 2 Connect a jumper wire by backprobing between ground and terminal No. 9 (White/Green wire) at ECM harness connector E7. (Scheme 54) With jumper wire connected air applied to EVAP VSV port "E" should flow from port "F". (Scheme 58) Remove jumper wire. With jumper wire removed, air applied to EVAP VSV port "E" should not flow from port "F". If EVAP VSV does not function as specified, go to next step. If EVAP VSV functions as specified, go to step 14.
  12. Turn ignition off. Connect all disconnected components. Check EVAP VSV operation. See «FUEL EVAPORATIVE SYSTEM»(ref-133221-S27194855212002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If EVAP VSV is okay, go to next step. If EVAP VSV is not okay, replace EVAP VSV. Also, clean vacuum hose between throttle body and EVAP VSV, and between EVAP VSV and charcoal canister, then check charcoal canister. See «FUEL EVAPORATIVE SYSTEM»(ref-133221-S27194855212002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article.
  13. Check for an open or short in wiring between EFI relay and EVAP VSV, and between EVAP VSV and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
  14. Disconnect canister closed valve VSV vacuum hoses. Turn ignition on. Access ECM behind glove box. see scheme 2 Connect a jumper wire by backprobing between ground and terminal No. 3 (Blue wire) at ECM harness connector E4. With jumper wire connected air applied to canister closed valve VSV port "E" should not flow from port "F". (Scheme 59) Remove jumper wire. With jumper wire removed, air applied to canister closed valve VSV port "E" should flow from port "F". If canister closed valve VSV does not function as specified, go to next step. If canister closed valve VSV functions as specified, go to step 17.
  15. Turn ignition off. Connect all disconnected components. Check canister closed valve VSV. See «FUEL EVAPORATIVE SYSTEM»(ref-133221-S27194855212002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If canister closed valve VSV is okay, go to next step. If canister closed valve VSV is defective, replace canister closed valve VSV and charcoal canister. Also, clean vacuum hose between charcoal canister and canister closed valve VSV.
  16. Check for an open or short in wiring between EFI relay and canister closed valve VSV, and between canister closed valve VSV and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
  17. Charcoal canister or fuel tank overfill check valve maybe defective. Check fuel evaporative system. See «FUEL EVAPORATIVE SYSTEM»(ref-133221-S27194855212002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Repair as necessary.

Scheme 58

Scheme 58
Scheme 58

Scheme 59

Scheme 59
Scheme 59
  1. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 1 (Red/White wire) and No. 9 (Brown wire) at ECM harness connector E6. (Scheme 54) Voltage should be 4.5-5.5 volts. If voltage is as specified, go to next step. If voltage is not as specified, replace ECM.
  2. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 9 (Brown wire) and No. 14 (Black wire) at ECM harness connector E6. Remove fuel tank cap. Turn ignition on. Voltage should be 3.0-3.6 volts. If voltage is not as specified, go to next step. If voltage is as specified, replace ECM.
  3. Check for open or short in wiring between vapor pressure sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.
  1. Test drive vehicle and check operation of speedometer. If speedometer is operating correctly, go to next step. If speedometer is not operating correctly, repair speedometer as necessary. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT.
  2. Access ECM behind glove box. see scheme 2 Raise and support one front wheel. Turn ignition on. Shift transaxle lever into Neutral. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 22 (Violet/White wire) at ECM harness connector E4. (Scheme 54) Observe voltage reading while rotating front wheel. Voltage should pulse between zero volts and 4.5-5.5 volts. If voltage is as specified, replace ECM. If voltage is not as specified, repair open or short in wiring between instrument cluster and ECM. See «WIRING DIAGRAMS»(ref-133228) article.
  1. Start engine and warm to normal operating temperature. Turn all accessories off. Ensure A/C is off. Shift transaxle lever into Neutral. Note engine RPM. Using a jumper wire, connect terminals No. 4 (White/Black wire) and No. 13 (Pink/Black wire) at DLC No. 3. (Scheme 53) Note engine RPM and compare RPM readings. If difference in engine speed is 100 RPM or less, go to next step. If difference in engine speed is more than 100 RPM, go to step 7.
  2. Turn ignition off. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 2 (Black/Red wire) at ECM harness connector E7. (Scheme 54) Voltage should be 9-14 volts. If voltage is not as specified, go to next step. If voltage is as specified, go to step 5.
  3. Turn ignition off. Disconnect IAC valve harness connector. Measure voltage between ground and terminal No. 2 (Black/Yellow wire) at IAC valve harness connector. If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, repair IAC valve power distribution circuit. See «WIRING DIAGRAMS»(ref-133228) article.
  4. Check for open or short in Black/Red wire between terminal No. 1 at IAC valve harness connector and terminal No. 2 at ECM harness connector E7. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace IAC valve.
  5. Check IAC valve operation. See «IDLE CONTROL SYSTEMS»(ref-133221-S00550503572002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem does not exist, go to next step. If problem exists, replace IAC valve.
  6. Remove IAC valve from throttle body. Check IAC valve and passages for carbon build-up and blockage. If problem exists, repair or replace as necessary. If problem does not exist, replace ECM.
  7. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, an open or short in A/C switch signal circuit may exist. Check A/C switch signal circuit. See MANUAL «ECHO»(ref-138689) article in AIR CONDITIONING & HEATING. Repair as necessary.
  1. Disconnect power steering oil pressure sensor harness connector. Connect 3 dry cell batteries (1.5 volts), a 180 k/ohm resister and a DVOM to power steering pressure sensor (component side) as shown in illustration. (Scheme 60) With power steering oil pressure at zero psi, voltage should be approximately.45 volt. With power steering oil pressure at 512 psi, voltage should be approximately 2.25 volts. With power steering oil pressure at 1010 psi, voltage should be approximately 4.05 volts. If voltage is as specified, go to next step. If voltage is not as specified, replace power steering oil pressure sensor.
  2. Check for open or short in wiring between ECM and power steering oil pressure sensor. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.

Scheme 60

Scheme 60
Scheme 60
  1. Check for spark at cylinder No. 1 by performing spark test. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Cylinder No. 1 is the front cylinder at timing chain end of engine. If spark exists, go to next step. If spark does not exist, go to step 4.
  2. Check for open or short in Yellow wire between ECM and ignition coil/ignitor No. 1. Also, check for open or short in Green/Red wire between ECM and ignition coil/ignitor No. 1. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
  3. Disconnect ignition coil/ignitor No. 1 harness connector. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 3 (Yellow wire) at ECM harness connector E7. (Scheme 54) Voltage should be 4.5-5.5 volts. If voltage is as specified, replace ignition coil/ignitor No. 1. If voltage is not as specified, replace ECM.
  4. Check for open or short in Green/Red wire between ECM and ignition coil/ignitor No. 1. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
  5. Access ECM behind glove box. see scheme 2 Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 22 (Green/Red wire) at ECM harness connector E7 while cranking engine. (Scheme 54) Voltage should be.1-4.5 volts. If voltage is not as specified, go to next step. If voltage is as specified, go to step 7.
  6. Disconnect ignition coil/ignitor No. 1 harness connector. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 22 (Green/Red wire) at ECM harness connector E7 while cranking engine. Voltage should be.1-5.0 volts. If voltage is as specified, replace ignition coil/ignitor No. 1. If voltage is not as specified, replace ECM.
  7. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black/Red wire) at ignition coil/ignitor No. 1 harness connector. (Scheme 61) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignition coil/ignitor No. 1 power source circuit. See «WIRING DIAGRAMS»(ref-133228) article.
  8. Check for open or short in wiring between ground and terminal No. 4 (White/Black wire) at ignition coil/ignitor No. 1 harness connector. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace ignition coil/ignitor No. 1.

Scheme 61

Scheme 61
Scheme 61
  1. Check for spark at cylinder No. 2 by performing spark test. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Cylinder No. 2 is second cylinder from timing chain end of engine 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 or short in Yellow wire between ECM and ignition coil/ignitor No. 2. Also, check for open or short in Green/Black wire between ECM and ignition coil/ignitor No. 2. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
  3. Disconnect ignition coil/ignitor No. 2 harness connector. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 3 (Yellow wire) at ECM harness connector E7. (Scheme 54) Voltage should be 4.5-5.5 volts. If voltage is as specified, replace ignition coil/ignitor No. 2. If voltage is not as specified, replace ECM.
  4. Check for open or short in Green/Black wire between ECM and ignition coil/ignitor No. 2. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
  5. Access ECM behind glove box. see scheme 2 Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 21 (Green/Black wire) at ECM harness connector E7 while cranking engine. (Scheme 54) Voltage should be.1-4.5 volts. If voltage is not as specified, go to next step. If voltage is as specified, go to step 7.
  6. Disconnect ignition coil/ignitor No. 2 harness connector. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 21 (Green/Black wire) at ECM harness connector E7 while cranking engine. Voltage should be.1-5.0 volts. If voltage is as specified, replace ignition coil/ignitor No. 2. If voltage is not as specified, replace ECM.
  7. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black/Red wire) at ignition coil/ignitor No. 2 harness connector. (Scheme 61) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignition coil/ignitor No. 2 power source circuit. See «WIRING DIAGRAMS»(ref-133228) article.
  8. Check for open or short in wiring between ground and terminal No. 4 (White/Black wire) at ignition coil/ignitor No. 2 harness connector. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace ignition coil/ignitor No. 2.
  1. Check for spark at cylinder No. 3 by performing spark test. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Cylinder No. 3 is third cylinder from timing chain end of engine. If spark exists, go to next step. If spark does not exist, go to step 4.
  2. Check for open or short in Yellow wire between ECM and ignition coil/ignitor No. 3. Also, check for open or short in Green/Orange wire between ECM and ignition coil/ignitor No. 3. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
  3. Disconnect ignition coil/ignitor No. 3 harness connector. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 3 (Yellow wire) at ECM harness connector E7. (Scheme 54) Voltage should be 4.5-5.5 volts. If voltage is as specified, replace ignition coil/ignitor No. 3. If voltage is not as specified, replace ECM.
  4. Check for open or short in Green/Orange wire between ECM and ignition coil/ignitor No. 3. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
  5. Access ECM behind glove box. see scheme 2 Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 20 (Green/Orange wire) at ECM harness connector E7 while cranking engine. (Scheme 54) Voltage should be.1-4.5 volts. If voltage is not as specified, go to next step. If voltage is as specified, go to step 7.
  6. Disconnect ignition coil/ignitor No. 3 harness connector. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 20 (Green/Orange wire) at ECM harness connector E7 while cranking engine. Voltage should be.1-5.0 volts. If voltage is as specified, replace ignition coil/ignitor No. 3. If voltage is not as specified, replace ECM.
  7. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black/Red wire) at ignition coil/ignitor No. 3 harness connector. (Scheme 61) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignition coil/ignitor No. 3 power source circuit. See «WIRING DIAGRAMS»(ref-133228) article.
  8. Check for open or short in wiring between ground and terminal No. 4 (White/Black wire) at ignition coil/ignitor No. 3 harness connector. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace ignition coil/ignitor No. 3.
  1. Check for spark at cylinder No. 4 by performing spark test. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Cylinder No. 4 is fourth cylinder from timing chain end of engine. If spark exists, go to next step. If spark does not exist, go to step 4.
  2. Check for open or short in Yellow wire between ECM and ignition coil/ignitor No. 4. Also, check for open or short in Green/Yellow wire between ECM and ignition coil/ignitor No. 4. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
  3. Disconnect ignition coil/ignitor No. 4 harness connector. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 3 (Yellow wire) at ECM harness connector E7. (Scheme 54) Voltage should be 4.5-5.5 volts. If voltage is as specified, replace ignition coil/ignitor No. 4. If voltage is not as specified, replace ECM.
  4. Check for open or short in Green/Yellow wire between ECM and ignition coil/ignitor No. 4. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
  5. Access ECM behind glove box. see scheme 2 Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 19 (Green/Yellow wire) at ECM harness connector E7 while cranking engine. (Scheme 54) Voltage should be.1-4.5 volts. If voltage is not as specified, go to next step. If voltage is as specified, go to step 7.
  6. Disconnect ignition coil/ignitor No. 4 harness connector. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 19 (Green/Yellow wire) at ECM harness connector E7 while cranking engine. Voltage should be.1-5.0 volts. If voltage is as specified, replace ignition coil/ignitor No. 4. If voltage is not as specified, replace ECM.
  7. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black/Red wire) at ignition coil/ignitor No. 4 harness connector. (Scheme 61) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignition coil/ignitor No. 4 power source circuit. See «WIRING DIAGRAMS»(ref-133228) article.
  8. Check for open or short in wiring between ground and terminal No. 4 (White/Black wire) at ignition coil/ignitor No. 4 harness connector. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace ignition coil/ignitor No. 4.
  1. Disconnect VVT sensor harness connector. Measure resistance between CMP sensor terminals (component side). Resistance should be 1630-2740 ohms with sensor temperature of 14-122°F (-10-50°C) and 2065-3225 ohms with sensor temperature of 122-212°F (50-100°C). If resistance is as specified, go to next step. If resistance is not as specified, replace CMP sensor.
  2. Check for open or short in wiring between ECM and VVT sensor. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
  3. Remove and inspect VVT sensor. Also, inspect camshaft timing pulley. If problem exists, replace VVT sensor and/or camshaft timing pulley as necessary. If problem does not exist, replace ECM.

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

Diagnosis & Repair (Using Toyota Hand-Held Tester)

  1. Check valve timing. See appropriate article in ENGINES. If problem does not exist, go to next step. If problem exists, repair as necessary.
  2. Connect hand-held tester to Data Link Connector (DLC) NO. 3. see scheme 1 Using hand-held tester, select ACTIVE TEST mode. Select VVT. Note idle speed when OCV is activated by hand-held tester. Idle speed should be normal with OCV off, and engine should idle rough or stalls when OCV is on. If idle speed does not function as specified, go to next step. If idle speed functions as specified, VVT is functioning properly at this time. DTC may have been set because of a foreign object that was temporarily caught in engine oil system but after a short time system returned to normal.
  3. Access ECM behind glove box. see scheme 2 Using oscilloscope, backprobe ECM harness connector and connect oscilloscope between terminals No. 10 (Red/White wire) and No. 23 (Red/Black wire) at ECM harness connector E7. (Scheme 54) Start engine and allow engine to idle. Ensure oscilloscope pattern is as shown in illustration. (Scheme 62) As engine speed is increased, waveform frequency ("A") should lengthen. If waveform pattern is as shown, go to next step. If waveform pattern is not as shown, replace ECM.
  4. Turn ignition off. Check VVT controller assembly for proper operation. See appropriate article in ENGINES. If problem does not exist, go to next step. If problem exists, replace VVT controller assembly and go to next step.
  5. Disconnect VVT OCV harness connector. Measure resistance between VVT OCV terminals (component side). (Scheme 63) Resistance should be 5.5-12.0 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace VVT OCV and go to next step.
  6. Check blockage in VVT OCV. Check oil check valve and oil pipe located under VVT OCV. If problem exists, repair as necessary. If problem does not exist, go to next step.
  7. Install all remove components and connect all disconnected harness connectors. Using hand-held tester, clear DTCs. Start engine and allow engine to idle. Turn ignition off. Turn ignition on and check for DTCs. If DTC P1349 is not present, no problem is indicated at this time. DTC may have been set because of a foreign object that was temporarily caught in engine oil system but after a short time system returned to normal. If DTC P1349 is present, replace ECM.

Scheme 62

Scheme 62
Scheme 62

Scheme 63

Scheme 63
Scheme 63

Diagnosis & Repair (Without Toyota Hand-Held Tester)

  1. Check valve timing. See appropriate article in ENGINES. If problem does not exist, go to next step. If problem exists, repair as necessary.
  2. Start engine and allow engine to idle. Note idle speed. Disconnect Variable Valve Timing (VVT) Oil Control Valve (OCV). VVT OCV is located on front cylinder head, next to intake manifold. Engine idle speed should not change. Using jumper wires, apply battery voltage and ground to VVT OCV terminals (component side). Engine should idle rough or stall. If VVT OCV operates as specified, go to next step. If VVT OCV does not operate as specified, go to step 4.
  3. Turn ignition off. Connect VVT OCV harness connector. Access ECM behind glove box. see scheme 2 Using oscilloscope, backprobe ECM harness connector and connect oscilloscope between terminals No. 10 (Red/White wire) and No. 23 (Red/Black wire) at ECM harness connector E7. (Scheme 54) Start engine and allow engine to idle. Ensure oscilloscope pattern is as shown in illustration. (Scheme 62) As engine speed is increased, waveform frequency ("A") should lengthen. If waveform pattern is as shown, go to next step. If waveform pattern is not as shown, replace ECM.
  4. Check VVT controller assembly for proper operation. See appropriate article in ENGINES. If problem does not exist, go to next step. If problem exists, replace VVT controller assembly and go to next step.
  5. With VVT OCV removed, connect a fused jumper wire between positive battery terminal and terminal No. 1 at VVT OCV. (Scheme 63) Connect another jumper wire between negative battery terminal and terminal No. 2 at VVT OCV and note VVT OCV plunger operation. With battery voltage applied, plunger on end of VVT OCV should extend. Disconnect a jumper wire. Without battery voltage applied, plunger should retract. If VVT OCV operates as specified, go to next step. If VVT OCV does not operate as specified, replace VVT OCV and go to next step.
  6. Check blockage in VVT OCV. Check oil check valve and oil pipe located under VVT OCV. If problem exists, repair as necessary. If problem does not exist, go to next step.
  7. Install remove components all and connect all disconnected harness connectors. Using scan tool, clear DTCs. Start engine and allow engine to idle. Turn ignition off. Turn ignition on and check for DTCs. If DTC P1349 is not present, no problem is indicated at this time. DTC may have been set because of a foreign object that was temporarily caught in engine oil system but after a short time system returned to normal. If DTC P1349 is present, replace ECM.
  1. Check stoplight operation. If stoplights 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.
  2. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 6 (Green/White wire) at ECM harness connector E7. (Scheme 54) 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 as specified, go to next step. If voltage is as specified, problem is intermittent. Check component and ECM connections.
  3. Check for open or short in wiring between ECM and stoplight switch. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
  1. Turn ignition off. Access ECM behind glove box. see scheme 2 Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 1 (Black/Yellow wire) at ECM harness connector E4. (Scheme 54) Voltage should be 9-14 volts. If voltage is not as specified, go to next step. If voltage is as specified, replace ECM.
  2. Remove and inspect EFI fuse (15-amp). EFI fuse is located in engine room junction box. If fuse is blown, repair short to ground in power distribution circuit as necessary and replace fuse. If fuse is okay, check circuit between EFI fuse and ECM. See «WIRING DIAGRAMS»(ref-133228) article. It may be necessary to check wiring between battery and EFI fuse. For additional wiring for EFI fuse to the battery, see POWER DISTRIBUTION article in «WIRING DIAGRAMS»(ref-133228). Repair wiring as necessary.
  1. Connect hand-held tester to Data Link Connector (DLC) No. 3. see scheme 1 Using hand-held tester, select ACTIVE TEST mode. Select VVT. Note idle speed when Variable Valve Timing (VVT) Oil Control Valve (OCV) is activated by hand-held tester. If idle speed does not function as specified, go to next step. If idle speed is normal with VVT OCV off, and engine idles rough or stalls when VVT OCV is on, VVT is functioning properly at this time. DTC may have been set because of a foreign object that was temporarily caught in engine oil system but after a short time system returned to normal.
  2. Start engine and allow engine to idle. Disconnect VVT OCV harness connector and note idle speed. Engine idle speed should not change. Using jumper wires, apply battery voltage and ground to VVT OCV terminals. Engine should idle rough or stall. If VVT OCV operates as specified, go to next step. If VVT OCV does not operate as specified, replace VVT OCV.
  3. Turn ignition off. Connect VVT OCV harness connector. Access ECM behind glove box. see scheme 2 Using oscilloscope, backprobe ECM harness connector. Connect oscilloscope between terminals No. 10 (Red/White wire) and No. 23 (Red/Black wire) at ECM harness connector E7. (Scheme 54) Start engine and allow engine to idle. Ensure oscilloscope pattern is as shown in illustration. (Scheme 62) As engine speed is increased, waveform frequency ("A") should lengthen. If waveform pattern is as shown, go to next step. If waveform pattern is not as shown, replace ECM.
  4. Check for an open or short in wiring between VVT OCV and ECM. If problem exists, repair wiring as necessary. If problem does not exist, problem is intermittent. Check component and ECM connections.
  1. Start engine and allow engine to idle. Disconnect Variable Valve Timing (VVT) Oil Control Valve (OCV) harness connector and note idle speed. VVT OCV is located on timing chain side of cylinder head. Engine idle speed should not change. Using jumper wires, apply battery voltage and ground to VVT OCV. Engine should idle rough or stall. If VVT OCV operates as specified, go to next step. If VVT OCV does not operate as specified, replace VVT OCV.
  2. Turn ignition off. Connect VVT OCV harness connector. Access ECM behind glove box. see scheme 2 Using oscilloscope, backprobe ECM harness connector. Connect oscilloscope between terminals No. 10 (Red/White wire) and No. 23 (Red/Black wire) at ECM harness connector E7. (Scheme 54) Start engine and allow engine to idle. Ensure oscilloscope pattern is as shown in illustration. (Scheme 62) As engine speed is increased, waveform frequency ("A") should lengthen. If waveform pattern is as shown, go to next step. If waveform pattern is not as shown, replace ECM.
  3. Check for an open or short in wiring between VVT OCV and ECM. If problem exists, repair wiring as necessary. If problem does not exist, problem is intermittent. Check component and ECM connections.

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

  1. Access ECM behind glove box. see scheme 2 Turn ignition on. Using DVOM, backprobe and measure voltage between ground and specified terminal at appropriate ECM harness connector. See «PARK/NEUTRAL POSITION SWITCH VOLTAGE»(ref-133206-S40466960422002021900000) table. (Scheme 54) If voltage is not as specified, go to next step. If voltage is as specified, no problem is indicated at this time. PARK/NEUTRAL POSITION SWITCH VOLTAGE Shift Lever Position ECM Terminal No. Volts Park (1) 5 Zero (2) 17 Zero (2) 18 Zero (2) 19 Zero (2) 22 9-14 Reverse (1) 5 Zero (2) 17 (3) 9-14 (2) 18 Zero (2) 19 Zero (2) 22 Zero Neutral (1) 5 Zero (2) 17 Zero (2) 18 Zero (2) 19 Zero (2) 22 Zero Drive (1) 5 9-14 (2) 17 Zero (2) 18 Zero (2) 19 Zero (2) 22 Zero 2 (1) 5 Zero (2) 17 Zero (2) 18 9-14 (2) 19 Zero (2) 22 Zero Low (1) 5 Zero (2) 17 Zero (2) 18 Zero (2) 19 9-14 (2) 22 Zero (1) Measure voltage between ground and terminal listed, at ECM harness connector E7. (Scheme 54) (2) Measure voltage between ground and terminal listed, at ECM harness connector E4. (Scheme 54) (3) Voltage may be slightly less due to lighting of reverse lights.
  2. Turn ignition off. Disconnect PNP switch harness connector. Check continuity between appropriate PNP switch terminals (component side) with shift lever in appropriate position. See «PARK/NEUTRAL POSITION SWITCH CONTINUITY»(ref-133206-S02758301042002021900000) table. (Scheme 64) If problem does not exist, go to next step. If problem exists, replace PNP switch. PARK/NEUTRAL POSITION SWITCH CONTINUITY Shift Lever Position Continuity Between Terminals No. Park 3 & 5; 6 & 9 Reverse 2 & 3 Neutral 1 & 3; 6 & 9 Drive 3 & 7 2 3 & 4 Low 3 & 8
  3. Check wiring between battery and PNP switch. Check wiring between PNP switch and ECM. See «WIRING DIAGRAMS»(ref-133228) article. It may be necessary to consult wiring diagram in appropriate «STARTERS»(ref-139867) article in STARTING & CHARGING SYSTEMS for additional PNP switch wiring. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.

Scheme 64

Scheme 64
Scheme 64

More articles — Engine Control System Self-Diagnostics