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Engine Control System Self-Diagnostics: Diagnosis Toyota Corolla IX

Testing & Diagnostics 16 illustrations ~12834 words

MALFUNCTION INDICATOR LIGHT INSPECTION

Note. CHECK engine light, located on instrument cluster, is referred to as Malfunction Indicator Light (MIL). 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. Malfunction Indicator Light (MIL) should come on and remain on. 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-133205-S29050310482002021900000) .
  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 «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-133205-S40050911422002021900000) .

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 Connect scan tool to Data Link Connector No. 3. see scheme 1 Retrieve DTCS and record any freeze frame data (if applicable). See «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-133205-S40050911422002021900000).
  3. Clear Trouble Codes Clear DTCs and freeze frame data. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-133205-S09622218542002021900000).
  4. Visual Inspection Inspect all connectors of suspect circuit or component. Ensure all connections are clean and tight.
  5. Confirm Symptoms & Trouble Codes Perform road test. Determine if original symptoms are still present. Retrieve DTCs. See «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-133205-S40050911422002021900000).
  6. Diagnose & Repair Diagnostic Trouble Codes Perform appropriate diagnosis and repair procedures under DIAGNOSTIC TESTS as necessary. For DTC descriptions, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-133205-S01067858722002021900000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If no DTCs are present, proceed to «TROUBLE SHOOTING - NO CODES»(ref-133220) article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.).
  7. Verification Procedure After repairs have been completed, clear all DTCs. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-133205-S09622218542002021900000). Perform road test. Ensure no DTCs are present 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, 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, or scan tool is switched from NORMAL mode to CHECK mode, all DTCs and freeze frame data will be erased. DO NOT switch modes until all DTCs and freeze frame data have been recorded.

CLEARING DIAGNOSTIC TROUBLE CODES

  1. After performing repairs, clear Engine Control Module (ECM) memory of all stored Diagnostic Trouble Codes (DTC) and freeze frame data. DTCs and freeze frame data may be cleared by using scan tool and scan tool manufacturer's instructions.
  2. DTCs and freeze frame data may also be cleared by removing EFI fuse from fuse block located in engine compartment. DTCs and freeze frame data may also be cleared by disconnecting negative battery cable. However, other memory functions (clock, radio, alarm, seats, etc.) will be cleared and must be reset.

TEST DRIVE CONFIRMATION

  1. On certain Diagnostic Trouble Codes (DTC), once DTC has been cleared from ECM memory, a DTC test drive confirmation test can be performed to verify repairs are made and that DTC does not reset. Test drive confirmation test will duplicate conditions required to set specified DTCs.
  2. Test drive confirmation test lists the procedure to be performed to check that DTC does not reset. Test drive confirmation tests apply only to specific DTCs. Test drive confirmation test will be included within proper DTC test under «DIAGNOSTIC TESTS»(ref-133205-S26089490592002021900000) .

DATA LINK CONNECTOR NO. 3 INSPECTION

  1. If scan tool displays UNABLE TO CONNECT TO VEHICLE when scan tool is connected, try scan tool on another vehicle. If scan tool operates on another vehicle, go to next step. If scan tool does not operate on another vehicle, problem is probably with 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. Repair as necessary. If connector and terminals are okay, go to next step.
  3. Check voltage and resistance between ground and specified terminal on DLC No. 3. See «DLC NO. 3 VOLTAGE & RESISTANCE SPECIFICATIONS»(ref-133205-S02682024532002021900000) table. (Scheme 53) If voltage and resistance readings are not as specified, check wiring circuit. See «WIRING DIAGRAMS»(ref-133228) article.
Terminal No. (Circuit) (1)Specification
4 (Chassis Ground)Less Than One Ohm
5 (Signal Ground)Less Than One Ohm
16 (Battery Voltage)9-14 Volts
(1) Terminal No. 7 provides a pulse generation during information transmission (BUS communication) from Engine Control Module (ECM).
(1)Terminal No. 7 provides a pulse generation during information transmission (BUS communication) from Engine Control Module (ECM).

DLC 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 (TP) Sensor Circuit
P0121Throttle Position (TP) Sensor Circuit Range/Performance
P0125Insufficient Coolant Temperature For Closed Loop Fuel Control
P0128Thermostat Malfunction
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
P0442Evaporative Emission Control System Leak Detected
P0446EVAP Vent Control Circuit
P0450EVAP Pressure Sensor Circuit
P0451EVAP Pressure Sensor Range/Performance
P0500Vehicle Speed Sensor Circuit
P0505Idle Air Control (IAC) System Circuit
P0750 (3)Shift Solenoid Valve No. 1 Malfunction
P0753 (3)Shift Solenoid Valve No. 1 Electrical Malfunction
P0755 (3)Shift Solenoid Valve No. 2 Malfunction
P0758 (3)Shift Solenoid Valve No. 2 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
P1335 (4)Crankshaft Position Sensor Circuit
P1346Variable Valve Timing Circuit Range/Performance
P1349Variable Valve Timing System Malfunction
P1520Stoplight Switch Signal Circuit (A/T Only)
P1600ECM BATT Circuit
P1656Oil Control Valve Malfunction
P1780Park/Neutral Position Switch Circuit (A/T Only)
(1) Some DTCs are two-trip detection logic code(s). For more information, see TWO-TRIP DETECTION LOGIC under SELF-DIAGNOSTIC SYSTEM. (2) If this DTC is set, ECM will enter fail-safe mode. (3) These DTCs only apply to models with electronically controlled transmissions. For testing procedures, see appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS. (4) MIL will not illuminate.
(1)Some DTCs are two-trip detection logic code(s). For more information, see TWO-TRIP DETECTION LOGIC under SELF-DIAGNOSTIC SYSTEM.
(2)If this DTC is set, ECM will enter fail-safe mode.
(3)These DTCs only apply to models with electronically controlled transmissions. For testing procedures, see appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS.
(4)MIL will not illuminate.

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. To identify ECM terminals referenced in testing, see illustration. (Scheme 55)or (Scheme 54).

Scheme 54

Scheme 54: DIAGNOSTIC TESTS
Scheme 54: DIAGNOSTIC TESTS

Scheme 55

Scheme 55
Scheme 55

Diagnosis & Repair

  1. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Start and warm engine to normal operating temperature. Using scan tool, monitor MAF flow rate. If scan tool reading is 0.0 gm/sec., go to next step. If scan tool reading 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 wire) at MAF meter harness connector. (Scheme 56) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, repair open in Black wire between engine compartment junction box and MAF meter. See «WIRING DIAGRAMS»(ref-133228) article.
  3. Turn ignition off. Connect MAF meter harness connector. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Ensure shift lever is in Neutral or Park. Ensure A/C switch is off. Start engine and let idle. Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 2 (Green wire) at ECM harness connector E5. On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 11 (Green wire) at ECM harness connector E8. (Scheme 55) (Scheme 54) If voltage is not.5-3.0 volts, go to next step. If voltage is.5-3.0 volts, replace ECM.
  4. Check for open or short in Green 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 below stereo, behind instrument panel, just in front of center console. see scheme 2 Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure resistance between ground and terminal No. 10 (Blue/White wire) at ECM harness connector E5. On models with 4-speed A/T transmission, measure resistance between ground and terminal No. 1 (Blue/White wire) at ECM harness connector E8. (Scheme 55) (Scheme 54) If resistance is one ohms or less, go to next step. If resistance is greater than one ohm, replace ECM.
  6. Check for open in Blue/White 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 56

Scheme 56
Scheme 56

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

  1. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on. Using scan tool, monitor IAT sensor temperature. If temperature displayed on scan tool is same as intake air temperature, problem is intermittent. Check component and ECM connections. If temperature displayed on scan tool is 284°F (140°C) or more, go to step 4. If temperature displayed on scan tool is -40°F (-40°C), go to next step.
  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 56) Turn ignition on. Using scan tool, monitor IAT sensor temperature. If temperature displayed on scan tool is 284°F (140°C) or more, replace MAF meter. If temperature displayed on scan tool is less than 284°F (140°C), go to next step.
  3. Turn ignition off. Remove jumper wire. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 On models with 3-speed A/T and M/T, connect a jumper wire by backprobing between terminals No. 3 (Yellow/Black wire) and No. 9 (Brown wire) at ECM harness connector E5. (Scheme 54) On models with 4-speed A/T transmission, connect a jumper wire by backprobing between terminals No. 22 (Yellow/Black wire) and No. 18 (Brown wire) at ECM harness connector E8. (Scheme 55) On all models, temperature displayed on scan tool should be 284°F (140°C) or more. If temperature displayed on scan tool is as specified, repair open in wiring between MAF meter and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If temperature displayed on scan tool is not as specified, replace ECM.
  4. Turn ignition off. Disconnect MAF meter harness connector. Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace MAF meter. If temperature displayed on scan tool is not -40°F (-40°C), go to next step.
  5. Turn ignition off. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 On models with 3-speed A/T and M/T, disconnect ECM harness connector E5. (Scheme 54) On models with 4-speed A/T transmission, disconnect ECM harness connector E8. (Scheme 55) On all models, turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), repair short in wiring between MAF meter and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If temperature displayed on scan tool is not -40°F (-40°C), replace ECM.
  1. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on. Using scan tool, monitor ECT sensor temperature. If temperature displayed on scan tool is same as actual coolant temperature, problem is intermittent. Check component and ECM connections. If temperature displayed on scan tool is 284°F (140°C) or more, go to step 4. If temperature displayed on scan tool is -40°F (-40°C), go to next step.
  2. Turn ignition off. Disconnect ECT sensor harness connector. Connect a jumper wire between ECT sensor harness connector terminals. Turn ignition on. Using scan tool, monitor ECT sensor temperature. If temperature displayed on scan tool is 284°F (140°C) or more, replace ECT sensor. If temperature displayed on scan tool is less than 284°F (140°C), go to next step.
  3. Turn ignition off. Remove jumper wire. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 On models with 3-speed A/T and M/T, connect a jumper wire by backprobing between terminals No. 4 (White wire) and No. 9 (Brown wire) at ECM harness connector E5. (Scheme 54) On models with 4-speed A/T transmission, connect a jumper wire by backprobing between terminals No. 14 (White wire) and No. 18 (Brown wire) at ECM harness connector E8. (Scheme 55) On all models, temperature displayed on scan tool should be 284°F (140°C) or more. If temperature displayed on scan tool is as specified, repair open in wiring between ECT sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If temperature displayed on scan tool is not as specified, replace ECM.
  4. Turn ignition off. Disconnect ECT sensor harness connector. Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace ECT sensor. If temperature displayed on scan tool is not -40°F (-40°C), go to next step.
  5. Turn ignition off. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 On models with 3-speed A/T and M/T, disconnect ECM harness connector E5. (Scheme 54) On models with 4-speed A/T transmission, disconnect ECM harness connector E8. (Scheme 55) On all models, turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), repair short in wiring between ECT sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If temperature displayed on scan tool is not -40°F (-40°C), replace ECM.
  1. If any other DTCs are displayed, diagnose and repair those DTCs first and retest. If only DTC P0116 is displayed, go to next step.
  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 scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on. Using scan tool, monitor throttle valve opening percentage. Opening percentage should be approximately 10 percent with fully closed throttle, and should be approximately 80 percent with throttle fully open. If percentages are as specified, problem is intermittent. Check component and ECM connections. If percentages are not as specified, go to next step.
  2. Turn ignition off. Disconnect TP sensor harness connector. Turn ignition on. Using DVOM, measure voltage between ground and terminal No. 1 (Yellow 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 exists, replace TP sensor. If problem does not exist, go to next step.
  4. Turn ignition off. Connect TP sensor harness connector. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between terminals No. 9 (Brown wire) and No. 11 (Light Green wire) at ECM harness connector E5. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between terminals No. 18 (Brown wire) and No. 23 (Light Green wire) at ECM harness connector E8. (Scheme 55) On all models, 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 below stereo, behind instrument panel, just in front of center console. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between terminals No. 1 (Yellow wire) and No. 9 (Brown wire) at ECM harness connector E5. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between terminals No. 2 (Yellow wire) and No. 18 (Brown wire) at ECM harness connector E8. (Scheme 55) On all models, voltage should be 4.5-5.5 volts. If voltage is as specified, repair open in Yellow 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 cause is; defective Throttle Position (TP) sensor.

Diagnostic Aids

After confirming DTC P0121, use scan tool to access CURRENT DATA to confirm throttle valve opening percentage with throttle open and closed. If percentage displayed on scan tool is always zero percent, VC circuit may be open or VTA circuit may be shorted. If percentage displayed on scan tool is always 100 percent, check for open in E2 circuit. Using scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.

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

  1. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Start and warm engine to normal operating temperature. Using 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 a rich signal is indicated for heated oxygen sensor No. 1 at least once, replace ECM. If heated oxygen sensor No. 1 does not display a rich signal at least once, go to next step.
  2. Check for open or short in wiring between heated oxygen sensor No. 1 and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem does not exists, go to next step. If problem exists, repair wiring as necessary.
  3. Using scan tool, check if a misfire has occurred by monitoring DTCs and DATA LIST. If a misfire has occurred, perform «DTC P0300: RANDOM MISFIRE DETECTED»(ref-133205-S28513488902002021900000). If misfire has not occurred, go to next step.
  4. Check exhaust system for leaks. If problem exists, repair as necessary. If problem does not exist, replace defective heated oxygen sensor No. 1.
  1. Remove and inspect cooling system thermostat. If problem exists, replace thermostat as necessary and retest. If problem does not exist, go to next step.
  2. If any other DTCs are displayed, diagnose and repair those DTCs first and retest. If only DTC P0128 is displayed, replace ECM.
  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 and warm engine to normal operating temperature with all accessories off. Drive vehicle at 31-40 MPH for 1-3 minutes. Stop vehicle and allow to idle for one minute. Repeat driving and idle part of test 3 times. If malfunction exists, MIL will illuminate.
  3. Start and warm engine to normal operating temperature. Drive vehicle at 31-40 MPH for 1-3 minutes. Stop vehicle and allow to idle for one minute. Repeat driving and idle part of test 3 times. Go to next step.
  4. Turn ignition off. Repeat step 3. If malfunction exists, MIL will illuminate.
  1. Check for open or short circuit in wiring harness between ECM and heated oxygen sensor. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
  2. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Start engine and warm to normal operating temperature. Monitor oxygen sensor output voltage and short-term fuel trim. If scan tool indicates a lean condition (.55 volt or less, +20 trim) or rich condition (.35 volt or more, -20 trim), check fuel trim system. See «DTC P0171 OR P0172: SYSTEM TOO LEAN/RICH»(ref-133205-S03156559372002021900000). If scan tool does not indicate a lean condition (.55 volt or less, +20 trim) or rich condition (.35 volt or more, -20 trim), go to next step.
  3. Start engine and increase engine speed to 2500 RPM for approximately 90 seconds. Let engine idle. Using scan tool, monitor heated oxygen senor No. 1 output voltage. Voltage should alternate repeatedly between less than.4 volt and more than.55 volt. If voltage is as specified, perform «TEST DRIVE CONFIRMATION»(ref-133205-S20260642212002021900000). If voltage is not as specified, replace heated oxygen sensor.

If any other DTCs are displayed, diagnose and repair those DTCs first and retest system. If only DTC P0133 is displayed, replace heated oxygen sensor No. 1.

  1. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 7 (Pink wire) at ECM harness connector E5. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 3 (Pink wire) at ECM harness connector E8. (Scheme 55) On all models, voltage should be 9-14 volts. If voltage is as specified, replace ECM. If voltage is not as specified, go to next step.
  2. Disconnect heated oxygen sensor No. 1 harness connector. Measure resistance between terminals B+ (Black wire) and HT (Pink wire) at heated oxygen sensor No. 1 (component side). (Scheme 57) Resistance should be 11-16 ohms at 68°F (20°C). If resistance is not as specified, replace heated oxygen sensor No. 1. If resistance is as specified, go to next step.
  3. Repair wiring between ECM and heated oxygen sensor No. 1, or between heated oxygen sensor No. 1 and engine room junction box. See «WIRING DIAGRAMS»(ref-133228) article.

Scheme 57

Scheme 57
Scheme 57
  1. If any other DTCs are displayed, diagnose and repair those DTCs first. If only DTC P0136 is displayed, go to next step.
  2. Check for open or short in wiring between ECM and heated oxygen sensor No. 2. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
  3. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Start and warm engine to normal operating temperature. Monitor heated oxygen sensor No. 2 output voltage. Snap accelerate engine to about 4000 RPM 3 times. Voltage should fluctuate from less than.4 volt to.5 volt or more. If voltage is as specified, problem is intermittent. Check component and ECM connections. If voltage is not as specified, replace heated oxygen sensor No. 2.
  1. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 15 (Pink wire) at ECM harness connector E5. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 6 (Pink wire) at ECM harness connector E8. (Scheme 55) On all models, voltage should be 9-14 volts. If voltage is as specified, replace ECM. If voltage is not as specified, go to next step.
  2. Disconnect heated oxygen sensor No. 2 harness connector. It might be necessary to remove passenger's seat to access harness connector. Measure resistance between terminals B+ (Black wire) and HT (Pink wire) at heated oxygen sensor No. 2 (component side). (Scheme 58) Resistance should be 11-16 ohms at 68°F (20°C). If resistance is not as specified, replace heated oxygen sensor No. 2. If resistance is as specified, go to next step.
  3. Repair wiring between ECM and heated oxygen sensor No. 2, or between heated oxygen sensor No. 2 and engine room junction box. See «WIRING DIAGRAMS»(ref-133228) article.

Scheme 58

Scheme 58
Scheme 58
  1. Ask customer if vehicle ran out of fuel. If vehicle ran out of fuel, clear DTCs and retest. If vehicle did not run out of fuel, go to next step.
  2. 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.
  3. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Start engine and warm to normal operating temperature. Monitor oxygen sensor output voltage and short-term fuel trim. If scan tool indicates a lean condition (.55 volt or less, +20 trim) or rich condition (.35 volt or more, -20 trim), go to next step. If scan tool does not indicate a lean condition (.55 volt or less, +20 trim) or rich condition (.35 volt or more, -20 trim), Check heated oxygen sensor No. 1 circuit. See «DTC P0130: HEATED OXYGEN SENSOR NO. 1 CIRCUIT»(ref-133205-S06372124782002021900000).
  4. 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 not as specified, repair as necessary. If fuel pressure is as specified, go to next step.
  5. Check fuel injectors. See «FUEL SYSTEMS»(ref-133221-S24954902022002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be 3.7-4.5 cu. in. (60-73 cc) every 15 seconds and difference in volume between each injector should be less than.8 cu. in. (13 cc). Injectors should not leak more than one drop every 12 minutes. If problem exists, repair as necessary. If problem does not exist, go to next step.
  6. Check Mass Airflow (MAF) meter and Engine Coolant Temperature (ECT) sensor. See «THEORY & OPERATION»(ref-133195) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace appropriate component. If problem does not exist, go to next step.
  7. Check spark and ignition system. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, go to next step.
  8. Check exhaust system for leaks. If problem exists, repair as necessary. If problem does not exist, replace ECM.
  1. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Record any DTCs and FREEZE FRAME data. Switch scan tool 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-133205-S16057840972002021900000) table. Turn ignition off after symptom is simulated the first time, then repeat test drive (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»(ref-133225) article. Also, check wiring and connectors for damage or poor connections. If problem exists, repair as necessary and perform «TEST DRIVE CONFIRMATION»(ref-133205-S22872602812002021900000). If problem does not exist, go to next step.
  2. Check spark and ignition system. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, go to next step.
  3. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM connector and measure voltage between ground and fuel injector terminals at appropriate ECM harness connector. See «IDENTIFYING FUEL INJECTOR TERMINALS»(ref-133205-S16313793552002021900000) table. (Scheme 55)or (Scheme 54). If voltage is 9-14 volts at each terminal, go to step 6. If voltage is not 9-14 volts at each terminal, go to next step. IDENTIFYING FUEL INJECTOR TERMINALS Fuel Injector No. Terminal No. Wire Color With 4A/T Transmission (1) 1 1 Yellow 2 2 Black/Red 3 3 White 4 4 Black Without 4A/T Transmission (2) 1 12 Yellow 2 11 Black/Red 3 25 White 4 24 Black (1) Terminals are located at ECM harness connector E7. (Scheme 55) (2) Terminals are located at ECM harness connector E4. (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 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 not as specified, repair as necessary. If fuel pressure is as specified, go to next step.
  7. Check fuel injectors. See «THEORY & OPERATION»(ref-133195) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Fuel injector volume should be 3.7-4.5 cu. in. (60-73 cc) every 15 seconds and difference in volume between each injector should be less than.8 cu. in. (13 cc). Injectors should not leak more than one drop every 12 minutes. If problem exists, repair as necessary. If problem does not exist, go to next step.
  8. Check Mass Airflow (MAF) meter and Engine Coolant Temperature (ECT) sensor. See «THEORY & OPERATION»(ref-133195) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace appropriate component. If problem does not exist, go to next step.
  9. Check engine compression. See «BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER»(ref-133196) article. Check valve clearance. 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 below stereo, behind instrument panel, just in front of center console. see scheme 2 On models with 3-speed A/T and M/T, disconnect ECM harness connector E4. (Scheme 54) On models with 4-speed A/T transmission, disconnect ECM harness connector E7. (Scheme 55) On all models use DVOM and backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure resistance between ground and terminal No. 18 (Black wire) at ECM harness connector E4. On models with 4-speed A/T transmission, measure resistance between ground and terminal No. 27 (Black wire) at ECM harness connector E7. On all models, resistance should be one megohm or more. If resistance is as specified, go to step 3. If resistance is not as specified, go to next step.
  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. Clear and then retrieve DTCs. If DTC P0325 is still displayed, replace ECM. If DTC P0325 is no longer displayed, replace knock sensor.

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 122-212°F (50-100°C).

  1. Disconnect CKP sensor harness connector. Measure resistance between CKP sensor terminals (component side). Resistance should be 1630-2740 ohms (cold sensor) or 2065-3225 ohms (hot sensor). If problem exists, replace CKP sensor. If problem does not exist, go to next step.
  2. Check for open or short in wiring between ECM and CKP sensor. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
  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 122-212°F (50-100°C).

  1. Disconnect CMP sensor harness connector. Measure resistance between CMP sensor terminals (component side). Resistance should be 835-1400 ohms (cold sensor) or 1060-1645 ohms (hot sensor). If resistance is not as specified, replace CMP sensor. If resistance is as specified, go to next step.
  2. Check for open or short in wiring between ECM and CMP sensor. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
  3. Remove and inspect CMP sensor. Also, inspect camshaft signal plate. If problem exists, replace CMP sensor and/or camshaft signal plate as necessary. If problem does not exist, replace ECM.
  1. If any other DTCs are displayed, diagnose and repair those DTCs first. If only DTC P0420 is displayed, go to next step.
  2. Check exhaust system for leaks. If problem exists, repair as necessary. If problem does not exist, go to next step.
  3. Check heated oxygen sensor No. 1. See «DTC P0130: HEATED OXYGEN SENSOR NO. 1 CIRCUIT»(ref-133205-S06372124782002021900000) . If problem exists, repair as necessary. If problem does not exist, go to next step.
  4. Check heated oxygen sensor No. 2. See «DTC P0136: HEATED OXYGEN SENSOR NO. 2 CIRCUIT»(ref-133205-S22595219432002021900000) 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. If fuel tank cap is not an OEM cap, replace fuel tank cap with an OEM cap. If fuel tank cap is an OEM cap, go to next step.
  3. Check if fuel tank cap is properly installed. If problem exists, install fuel tank cap properly. If fuel tank cap is properly installed, go to next step.
  4. Check for damaged fuel tank cap and gasket. If problem exists, replace fuel tank cap with OEM cap. If problem does not exist, go to next step.
  5. Remove fuel tank cap. Visually inspect fuel tank filler neck for damage. If problem exists, replace fuel tank filler neck as necessary. If problem does not exist, go to next step.
  6. Check vacuum hoses between vapor pressure sensor and fuel tank, and between charcoal canister and pressure switching valve VSV. Check hoses for correct installation, looseness and damage. If problem exists, repair vacuum hoses as necessary. If problem does not exist, go to next step.
  7. Check hose and tube between fuel tank and charcoal canister for correct installation and damage. If problem exists, repair as necessary. If problem does not exist, go to next step.
  8. Check charcoal canister for damage. If problem exists, repair or replace as necessary. If problem does not exist, go to next step.
  9. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between terminals No. 1 (Yellow wire) and No. 9 (Brown wire) at ECM harness connector E5. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between terminals No. 2 (Yellow wire) and No. 18 (Brown wire) at ECM harness connector E8. (Scheme 55) On all models, voltage should be 4.5-5.5 volts. If voltage is not as specified, replace ECM. If voltage is as specified, go to next step.
  10. Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between terminal No. 17 (Blue wire) at ECM harness connector E4 and terminal No. 9 (Brown wire) at ECM harness connector E5. On models with 4-speed A/T transmission, measure voltage between terminals No. 9 (Blue wire) and No. 18 (Brown wire) at ECM harness connector E5. On all models, disconnect vacuum hose from vapor pressure sensor. (Scheme 59) Vapor pressure sensor is mounted on charcoal canister. Connect a vacuum pump to vapor pressure sensor. Voltage should be 2.9-3.7 volts without vacuum applied, and.5 volt or less with 1.8 in. Hg applied. If voltage is as specified, go to step 12. If voltage is not as specified, go to next step.
  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.

Scheme 59

Scheme 59
Scheme 59
  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. If fuel tank cap is not an OEM cap, replace fuel tank cap with an OEM cap. If fuel tank cap is an OEM cap, go to next step.
  3. Check if fuel tank cap is properly installed. If problem exists, install fuel tank cap properly. If fuel tank cap is properly installed, go to next step.
  4. Check for damaged fuel tank cap and gasket. If problem exists, replace fuel tank cap with OEM cap. If problem does not exist, go to next step.
  5. Remove fuel tank cap. Visually inspect fuel tank filler neck for damage. If problem exists, replace fuel tank filler neck as necessary. If problem does not exist, go to next step.
  6. Check vacuum hoses between vapor pressure sensor and fuel tank, and between charcoal canister and pressure switching valve VSV. Check hoses for correct installation, looseness and damage. If problem exists, repair vacuum hoses as necessary. If problem does not exist, go to next step.
  7. Check hose and tube between fuel tank and charcoal canister for correct installation and damage. If problem exists, repair as necessary. If problem does not exist, go to next step.
  8. Check all EVAP system electrical component connections. If problem exists, repair as necessary. If problem does not exist, go to next step.
  9. Check vacuum hoses between charcoal canister and fuel tank, and between fuel filler neck and fuel tank. If problem exists, repair as necessary. If problem does not exist, go to next step.
  10. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between terminals No. 1 (Yellow wire) and No. 9 (Brown wire) at ECM harness connector E5. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between terminals No. 2 (Yellow wire) and No. 18 (Brown wire) at ECM harness connector E8. (Scheme 55) On all models, voltage should be 4.5-5.5 volts. If voltage is not as specified, replace ECM. If voltage is as specified, go to next step.
  11. Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between terminal No. 17 (Blue wire) at ECM harness connector E4 and terminal No. 9 (Brown wire) at ECM harness connector E5. On models with 4-speed A/T transmission, measure voltage between terminals No. 9 (Blue wire) and No. 18 (Brown wire) at ECM harness connector E8. On all models, disconnect vacuum hose from vapor pressure sensor. (Scheme 59) Vapor pressure sensor is mounted on charcoal canister. Connect a vacuum pump to vapor pressure sensor. Voltage should be 2.9-3.7 volts without vacuum applied, and.5 volt or less with 1.8 in. Hg applied. If voltage is as specified, go to step 13. If voltage is not as specified, go to next step.
  12. Check for an open or short in wiring between vapor pressure sensor and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.
  13. Disconnect EVAP VSV vacuum hoses. Turn ignition on. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 On models with 3-speed A/T and M/T, connect a jumper wire by backprobing between ground and terminal No. 7 (Blue/Black wire) at ECM harness connector E4. (Scheme 54) On models with 4-speed A/T transmission, connect a jumper wire by backprobing between ground and terminal No. 4 (Blue/Black wire) at ECM harness connector E8. (Scheme 55) On all models, with jumper wire connected air applied to EVAP VSV port "E" should flow from port "F". (Scheme 60) Remove jumper wire. With jumper wire removed, air applied to EVAP VSV port "E" should not flow from port "F". If EVAP VSV functions as specified, go to step 16. If EVAP VSV does not function as specified, go to next step.
  14. Connect all disconnected components. Check EVAP VSV operation. See «FUEL EVAPORATIVE SYSTEM»(ref-133221-S27194855212002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If EVAP VSV is okay, go to next step. If EVAP VSV is not okay, replace EVAP VSV. 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.
  15. Check for an open or short in wiring between engine room junction box and EVAP VSV, and between EVAP VSV and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
  16. Disconnect canister closed valve VSV vacuum hoses. Turn ignition on. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 On models with 3-speed A/T and M/T, connect a jumper wire by backprobing between ground and terminal No. 5 (Blue/Black wire) at ECM harness connector E4. On models with 4-speed A/T transmission, connect a jumper wire by backprobing between ground and terminal No. 17 (Blue/Black wire) at ECM harness connector E7. On all models, with jumper wire connected air applied to canister closed valve VSV port "B" should not flow from port "A". (Scheme 61) Remove jumper wire. With jumper wire removed, air applied to canister closed valve VSV port "B" should flow from port "A". If canister closed valve VSV does not function as specified, go to next step. If canister closed valve VSV functions as specified, go to step 19.
  17. Connect all disconnected components. Check canister closed valve VSV. See «FUEL EVAPORATIVE SYSTEM»(ref-133221-S27194855212002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If canister closed valve VSV is okay, go to next step. If canister closed valve VSV is defective, replace canister closed valve VSV and charcoal canister. Also, clean vacuum hose between charcoal canister and canister closed valve VSV.
  18. Check for an open or short in wiring between engine room junction box and canister closed valve VSV, and between canister closed valve VSV and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
  19. Disconnect pressure switching valve VSV vacuum hoses. Turn ignition on. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 On models with 3-speed A/T and M/T, connect a jumper wire by backprobing between ground and terminal No. 4 (Red wire) at ECM harness connector E4. On models with 4-speed A/T transmission, connect a jumper wire by backprobing between ground and terminal No. 22 (Red wire) at ECM harness connector E7. On all models, with jumper wire connected air applied to pressure switching valve VSV port "E" should flow from port "F". (Scheme 62) Remove jumper wire. With jumper wire removed, air applied to pressure switching valve VSV port "E" should not flow from port "F". If pressure switching valve VSV functions as specified, go to step 22. If pressure switching valve VSV does not function as specified, go to next step.
  20. Connect all disconnected components. Check pressure switching valve VSV. See «FUEL EVAPORATIVE SYSTEM»(ref-133221-S27194855212002021900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If pressure switching valve VSV is defective, replace pressure switching valve VSV and charcoal canister. Also, clean vacuum hose between charcoal canister and pressure switching valve VSV, and between pressure switching valve VSV and fuel tank. If pressure switching valve VSV is okay, go to next step.
  21. Check for an open or short in wiring between engine room junction box and pressure switching valve VSV, and between pressure switching valve VSV and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
  22. Connect all disconnected components. 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 60

Scheme 60
Scheme 60

Scheme 61

Scheme 61
Scheme 61

Scheme 62

Scheme 62
Scheme 62
  1. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Turn ignition on. Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between terminals No. 1 (Yellow wire) and No. 9 (Brown wire) at ECM harness connector E5. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between terminals No. 2 (Yellow wire) and No. 18 (Brown wire) at ECM harness connector E8. (Scheme 55) On all models, voltage should be 4.5-5.5 volts. If voltage is not as specified, replace ECM. If voltage is as specified, go to next step.
  2. Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between terminal No. 17 (Blue wire) at ECM harness connector E4 and terminal No. 9 (Brown wire) at ECM harness connector E5. On models with 4-speed A/T transmission, measure voltage between terminals No. 9 (Blue wire) and No. 18 (Brown wire) at ECM harness connector E8. On all models, disconnect vacuum hose from vapor pressure sensor. (Scheme 59) Connect a vacuum pump to vapor pressure sensor. Voltage should be 2.9-3.7 volts without vacuum applied, and.5 volt or less with 1.8 in. Hg applied. If voltage is as specified, replace ECM. If voltage is not as specified, go to next step.
  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 not operating correctly, repair speedometer as necessary. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. If speedometer is operating correctly, go to next step.
  2. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Raise and support one front wheel. Turn ignition on. Shift transaxle lever into Neutral. Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 9 (Violet/White wire) at ECM harness connector E6. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 22 (Violet/White wire) at ECM harness connector E9. (Scheme 55) On all models, 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.

Diagnosis & Repair (Using Toyota Hand-Held Tester)

  1. Connect hand-held tester to Data Link Connector (DLC) No. 3. see scheme 1 Start engine and warm to normal operating temperature. Turn all accessories off. Ensure A/C is off. Place transmission in Neutral. Note idle speed. Using hand-held tester, select ACTIVE TEST mode and switch TE1 on. Note engine RPM and compare RPM readings. If difference in engine speed is more than 100 RPM, go to step 8. If difference in engine speed is 100 RPM or less, go to next step.
  2. Turn ignition off. Turn ignition on. Using hand-held tester, check IAC valve duty ratio. If duty ratio is 27-47 percent, go to next step. If duty ratio is not 27-47 percent, replace ECM.
  3. Check operation of IAC valve. See «IDLE CONTROL SYSTEMS»(ref-133221-S00550503572002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If IAC valve does not operate properly, go to step 5. If IAC valve operates properly, go to next step.
  4. 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, go to step 8.
  5. Turn ignition off. Disconnect IAC valve harness connector. Turn ignition on. Measure voltage between ground and terminal No. 2 (Black wire) at IAC valve harness connector. If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, repair power distribution circuit as necessary. See «WIRING DIAGRAMS»(ref-133228) article.
  6. Check for open in Brown wire between ground and terminal No. 3 at IAC valve harness connector. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
  7. Check for open or short in Black/Blue wire between IAC valve and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace IAC valve.
  8. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, an open or short in A/C switch signal circuit may exist. Check A/C amplifier. See MANUAL «COROLLA»(ref-138687) article in AIR CONDITIONING & HEATING. Repair as necessary.

Diagnosis & Repair (Using OBD-II Scan Tool)

  1. Start engine and warm to normal operating temperature. Turn all accessories off. Ensure A/C is off. Shift transaxle lever into Neutral. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Note engine RPM. Using a jumper wire, connect terminals TE1 and E1 at DLC No. 1 in engine compartment. (Scheme 63) Note engine RPM and compare RPM readings. If difference in engine speed is more than 100 RPM, go to step 9. If difference in engine speed is 100 RPM or less, go to next step.
  2. Turn ignition off. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 On models with 3-speed A/T and M/T, connect an oscilloscope by backprobing between ground and terminal No. 15 (Blue/Black wire) at ECM harness connector E4. (Scheme 54) On models with 4-speed A/T transmission, connect an oscilloscope by backprobing between ground and terminal No. 18 (Blue/Black wire) at ECM harness connector E7. (Scheme 55) On all models, start engine and let idle. Oscilloscope waveform should be as illustrated. (Scheme 64) If waveform is as shown, go to step 6. If waveform is not as shown, go to next step.
  3. Turn ignition off. Turn ignition on. Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 15 (Blue/Black wire) at ECM harness connector E4. On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 18 (Blue/Black wire) at ECM harness connector E7. On all models, voltage should be 9-14 volts. If voltage is as specified, replace ECM. If voltage is not as specified, go to next step.
  4. Turn ignition off. Disconnect IAC valve harness connector. Measure voltage between ground and terminal No. 2 (Black 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.
  5. Check for open or short in Blue/Black wire between IAC valve and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace IAC valve.
  6. Check IAC valve operation. See «IDLE CONTROL SYSTEMS»(ref-133221-S00550503572002021900000) in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, go to next step. If problem does not exist, go to step 8.
  7. Check for open in Brown wire between ground and terminal No. 3 at IAC valve harness connector. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace IAC valve.
  8. 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, go to next step.
  9. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, an open or short in A/C switch signal circuit may exist. Check A/C amplifier. See MANUAL «COROLLA»(ref-138687) article in AIR CONDITIONING & HEATING. Repair as necessary.

Scheme 63

Scheme 63
Scheme 63

Scheme 64

Scheme 64
Scheme 64
  1. Check for spark at misfiring cylinder. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If spark exists, go to next step. If spark does not exist, go to step 4.
  2. Check for open or short in Blue/Yellow wire between ECM and ignition coil/ignitor No. 1. Also, check for open or short in Red/Blue wire between ECM and ignition coil/ignitor No. 1. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
  3. Disconnect ignition coil/ignitor No. 1 harness connector. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Turn ignition on. Using DVOM, backprobe at ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 3 (Blue/Yellow wire) at ECM harness connector E4. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 25 (Blue/Yellow wire) at ECM harness connector E7. (Scheme 55) On all models, 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 Red/Blue wire between ECM and ignition coil/ignitor No. 1. 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 below stereo, behind instrument panel, just in front of center console. see scheme 2 Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 20 (Red/Blue wire) at ECM harness connector E4 while cranking engine. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 10 (Red/Blue wire) at ECM harness connector E7 while cranking engine. (Scheme 55) On all models, 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. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 20 (Red/Blue wire) at ECM harness connector E4 while cranking engine. On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 10 (Red/Blue wire) at ECM harness connector E7 while cranking engine. On all models, 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/White wire) at ignition coil/ignitor No. 1 harness connector. (Scheme 65) 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 (Brown 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 65

Scheme 65
Scheme 65
  1. Check for spark at misfiring cylinder. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If spark exists, go to next step. If spark does not exist, go to step 4.
  2. Check for open or short in Blue/Yellow wire between ECM and ignition coil/ignitor No. 2. Also, check for open or short in Yellow/Green 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.
  3. Disconnect ignition coil/ignitor No. 2 harness connector. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Turn ignition on. Using DVOM, backprobe at ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 3 (Blue/Yellow wire) at ECM harness connector E4. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 25 (Blue/Yellow wire) at ECM harness connector E7. (Scheme 55) On all models, 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 Yellow/Green 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 below stereo, behind instrument panel, just in front of center console. see scheme 2 Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 21 (Yellow/Green wire) at ECM harness connector E4 while cranking engine. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 11 (Yellow/Green wire) at ECM harness connector E7 while cranking engine. (Scheme 55) On all models, 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. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 21 (Yellow/Green wire) at ECM harness connector E4 while cranking engine. On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 11 (Yellow/Green wire) at ECM harness connector E7 while cranking engine. On all models, 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/White wire) at ignition coil/ignitor No. 2 harness connector. (Scheme 65) 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 (Brown 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 misfiring cylinder. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If spark exists, go to next step. If spark does not exist, go to step 4.
  2. Check for open or short in Blue/Yellow wire between ECM and ignition coil/ignitor No. 3. Also, check for open or short in Gray wire between ECM and ignition coil/ignitor No. 3. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
  3. Disconnect ignition coil/ignitor No. 3 harness connector. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Turn ignition on. Using DVOM, backprobe at ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 3 (Blue/Yellow wire) at ECM harness connector E4. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 25 (Blue/Yellow wire) at ECM harness connector E7. (Scheme 55) On all models, 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 Gray wire between ECM and ignition coil/ignitor No. 3. 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 below stereo, behind instrument panel, just in front of center console. see scheme 2 Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 22 (Gray wire) at ECM harness connector E4 while cranking engine. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 12 (Gray wire) at ECM harness connector E7 while cranking engine. (Scheme 55) On all models, 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. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 22 (Gray wire) at ECM harness connector E4 while cranking engine. On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 12 (Gray wire) at ECM harness connector E7 while cranking engine. On all models, 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/White wire) at ignition coil/ignitor No. 3 harness connector. (Scheme 65) 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 (Brown 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 misfiring cylinder. See «IGNITION SYSTEMS»(ref-133196-S22458590502002021900000) in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If spark exists, go to next step. If spark does not exist, go to step 4.
  2. Check for open or short in Blue/Yellow wire between ECM and ignition coil/ignitor No. 4. Also, check for open or short in White wire between ECM and ignition coil/ignitor No. 4. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
  3. Disconnect ignition coil/ignitor No. 4 harness connector. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Turn ignition on. Using DVOM, backprobe at ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 3 (Blue/Yellow wire) at ECM harness connector E4. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 25 (Blue/Yellow wire) at ECM harness connector E7. (Scheme 55) On all models, 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 White wire between ECM and ignition coil/ignitor No. 4. 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 below stereo, behind instrument panel, just in front of center console. see scheme 2 Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 23 (White wire) at ECM harness connector E4 while cranking engine. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 13 (White wire) at ECM harness connector E7 while cranking engine. (Scheme 55) On all models, 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. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 23 (White wire) at ECM harness connector E4 while cranking engine. On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 13 (White wire) at ECM harness connector E7 while cranking engine. On all models, 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/White wire) at ignition coil/ignitor No. 4 harness connector. (Scheme 65) 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 (Brown 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.

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

  1. Check valve timing. See appropriate article in ENGINES. If problem exists, repair as necessary. If problem does not exist, go to next step.
  2. Connect hand-held tester to Data Link Connector (DLC) No. 3. see scheme 1 Using hand-held tester, select ACTIVE TEST mode. Select VVT. Note idle speed when VVT OCV is activated by hand-held tester. Idle speed should be normal with VVT OCV off, and engine should idle rough or stalls when VVT OCV is on. If idle speed functions as specified, VVT is functioning properly at this time. DTC may have been set because of a foreign object that was temporarily caught in the engine oil system but after a short time system returned to normal. If idle speed does not function as specified, go to next step.
  3. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Using oscilloscope, backprobe ECM harness connector. On models with 3-speed A/T and M/T, connect oscilloscope between terminals No. 1 (Red wire) and No. 2 (Black wire) at ECM harness connector E4. (Scheme 54) On models with 4-speed A/T transmission, connect oscilloscope between terminals No. 23 (Red wire) and No. 24 (Black wire) at ECM harness connector E7. (Scheme 55) On all models, start engine and let idle. Ensure oscilloscope pattern is as shown in illustration. (Scheme 66) 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 exists, replace VVT controller assembly and go to next step. If problem does not exist, go to next step.
  5. Disconnect VVT OCV harness connector. Measure resistance between VVT OCV terminals (component side). Resistance should be 6.9-7.9 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace VVT OCV.
  6. Remove VVT OCV. Connect a fused jumper wire between positive battery terminal and terminal No. 1 at VVT OCV. (Scheme 67) Connect another jumper wire between negative battery terminal and terminal No. 2 at VVT OCV and note VVT OCV plunger operation. With battery voltage applied, plunger on end of VVT OCV should extend. Disconnect a jumper wire. Without battery voltage applied, plunger should retract. If VVT OCV operates as specified, go to next step. If VVT OCV does not operate as specified, replace VVT OCV and go to next step.
  7. Check blockage in VVT OCV. Check oil check valve and oil pipe located under VVT OCV. If problem exists, repair as necessary. If problem does not exist, go to next step.
  8. Install all remove components and connect all disconnected harness connectors. Using hand-held tester, clear DTCs. Start engine and allow it to idle. Turn ignition off. Turn ignition on and check for DTCs. If DTC P1349 is not present, no problem is indicated at this time. DTC may have been set because of a foreign object that was temporarily caught in the engine oil system but after a short time system returned to normal. If DTC P1349 is present, replace ECM.

Scheme 66

Scheme 66
Scheme 66

Scheme 67

Scheme 67
Scheme 67
  1. Check valve timing. See appropriate article in ENGINES. If problem exists, repair as necessary. If problem does not exist, go to next step.
  2. Start engine and allow it to idle. Disconnect Variable Valve Timing (VVT) Oil Control Valve (OCV) and note idle speed. VVT OCV is located on front cylinder head, next to intake manifold. Engine idle speed should not change. Using jumper wires, apply battery voltage and ground to VVT OCV terminals (component side). Engine should idle rough or stall. If VVT OCV operates as specified, go to next step. If VVT OCV does not operate as specified, go to step 4.
  3. Turn ignition off. Connect VVT OCV harness connector. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Using oscilloscope, backprobe ECM harness connector. On models with 3-speed A/T and M/T, connect oscilloscope between terminals No. 1 (Red wire) and No. 2 (Black wire) at ECM harness connector E4. (Scheme 54) On models with 4-speed A/T transmission, connect oscilloscope between terminals No. 23 (Red wire) and No. 24 (Black wire) at ECM harness connector E7. (Scheme 55) On all applications, start engine and let idle. Ensure oscilloscope pattern is as shown in illustration. (Scheme 66) As engine speed is increased, waveform frequency ("A") should lengthen. If waveform pattern is as shown, no problem is indicated at this time. DTC may have been set because of a foreign object that was temporarily caught in the engine oil system but after a short time system returned to normal. If waveform pattern is not as shown, replace ECM.
  4. Check VVT controller assembly for proper operation. See appropriate article in ENGINES. If problem exists, replace VVT controller assembly and go to next step. If problem does not exist, go to next step.
  5. Disconnect VVT OCV harness connector. Measure resistance between VVT OCV terminals (component side). Resistance should be 6.9-7.9 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace VVT OCV.
  6. Remove VVT OCV. Connect a fused jumper wire between positive battery terminal and terminal No. 1 at VVT OCV. (Scheme 67) Connect another jumper wire between negative battery terminal and terminal No. 2 at VVT OCV and note VVT OCV plunger operation. With battery voltage applied, plunger on end of VVT OCV should extend. Disconnect a jumper wire. Without battery voltage applied, plunger should retract. If VVT OCV operates as specified, go to next step. If VVT OCV does not operate as specified, replace VVT OCV and go to next step.
  7. Check blockage in VVT OCV. Check oil check valve and oil pipe located under VVT OCV. If problem exists, repair as necessary. If problem does not exist, go to next step.
  8. Install remove components all and connect all disconnected harness connectors. Using scan tool, clear DTCs. Start engine and allow it to idle. Turn ignition off. Turn ignition on and check for DTCs. If DTC P1349 is not present, no problem is indicated at this time. DTC may have been set because of a foreign object that was temporarily caught in the engine oil system but after a short time system returned to normal. If DTC P1349 is present, replace ECM.
  1. Check stoplight operation. If stoplights do not operate properly, repair as necessary and retest system. See EXTERIOR LIGHTS article in ACCESSORIES & EQUIPMENT. If stoplights operate properly, go to next step.
  2. Access ECM below stereo, behind instrument panel, just in front of center console. 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 E9. (Scheme 55) 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 wiring and connectors.
  3. Check for 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 below stereo, behind instrument panel, just in front of center console. see scheme 2 Using DVOM, backprobe ECM harness connector. On models with 3-speed A/T and M/T, measure voltage between ground and terminal No. 1 (Red/White wire) at ECM harness connector E6. (Scheme 54) On models with 4-speed A/T transmission, measure voltage between ground and terminal No. 1 (Red/White wire) at ECM harness connector E10. (Scheme 55) On all models, voltage should be 9-14 volts. If voltage is as specified, replace ECM. If voltage is not as specified, go to next step.
  2. Remove and inspect EFI fuse (15-amp). EFI fuse is located in engine room junction box. Replace fuse as necessary. If fuse is okay, check circuit between EFI fuse and ECM. See «WIRING DIAGRAMS»(ref-133228) article. 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 OCV is activated by hand-held tester. If idle speed is normal with OCV off, and engine idles rough or stalls when 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 the engine oil system but after a short time system returned to normal. If idle speed does not function as specified, go to next step.
  2. Start engine and allow it to idle. Disconnect Oil Control Valve (OCV) harness connector and note idle speed. Engine idle speed should not change. Using jumper wires, apply battery voltage and ground to OCV terminals. Engine should idle rough or stall. If OCV operates as specified, go to next step. If OCV does not operate as specified, replace OCV.
  3. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Using oscilloscope, backprobe ECM harness connector. On models with 3-speed A/T and M/T, connect oscilloscope between terminals No. 1 (Red wire) and No. 2 (Black wire) at ECM harness connector E4. (Scheme 54) On models with 4-speed A/T transmission, connect oscilloscope between terminals No. 23 (Red wire) and No. 24 (Black wire) at ECM harness connector E7. (Scheme 55) On all models, start engine and let idle. Ensure oscilloscope pattern is as shown in illustration. (Scheme 66) 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 OCV and ECM. If problem exists, repair wiring as necessary. If problem does not exist, problem is intermittent. Check component and ECM connections.
  1. Start engine and allow it to idle. Disconnect Oil Control Valve (OCV) harness connector and note idle speed. OCV is located in each cylinder head, underneath lower intake manifold. Engine idle speed should not change. Using jumper wires, apply battery voltage and ground to OCV. Engine should idle rough or stall. If OCV operates as specified, go to next step. If OCV does not operate as specified, replace OCV.
  2. Access ECM below stereo, behind instrument panel, just in front of center console. see scheme 2 Using oscilloscope, backprobe ECM harness connector. On models with 3-speed A/T and M/T, connect oscilloscope between terminals No. 1 (Red wire) and No. 2 (Black wire) at ECM harness connector E4. (Scheme 54) On models with 4-speed A/T transmission, connect oscilloscope between terminals No. 23 (Red wire) and No. 24 (Black wire) at ECM harness connector E7. (Scheme 55) On all models, start engine and let idle. Ensure oscilloscope pattern is as shown in illustration. (Scheme 66) 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 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 below stereo, behind instrument panel, just in front of center console. see scheme 2 Turn ignition on. Using DVOM, backprobe and measure voltage between ground and specified terminal at ECM harness connector E9. See «PARK/NEUTRAL POSITION SWITCH VOLTAGE»(ref-133205-S37866260812002021900000) table. (Scheme 55) If voltage is as specified, no problem is indicated at this time. If voltage is not as specified, go to next step. PARK/NEUTRAL POSITION SWITCH VOLTAGE Shift Lever Position (1) Terminal No. Volts Park & Neutral 2 Zero 3 Zero 12 Zero 13 Zero Reverse 2 (2) 9-14 3 Zero 12 Zero 13 (2) 9-14 Drive 2 Zero 3 Zero 12 Zero 13 9-14 2 2 Zero 3 9-14 12 Zero 13 9-14 Low 2 Zero 3 Zero 12 9-14 13 9-14 (1) Measure voltage between ground and terminal listed, at ECM harness connector E9. (Scheme 55) (2) Voltage may be slightly less due to lighting of reverse lights.
  2. Disconnect PNP switch harness connector. Check continuity between appropriate PNP switch terminals (component side) with shift lever in appropriate position. See «PARK/NEUTRAL POSITION SWITCH CONTINUITY»(ref-133205-S28782017062002021900000) table. (Scheme 68) If problem exists, replace PNP switch. If problem does not exist, go to next step. PARK/NEUTRAL POSITION SWITCH CONTINUITY Shift Lever Position Continuity Between Terminals No. Park 1 & 3; 6 & 9 Reverse 2 & 3 Neutral 3 & 5; 6 & 9 Drive 3 & 7 2 3 & 4 Low 3 & 8
  3. Check wiring between battery and PNP switch. Check wiring between PNP switch and ECM. See «WIRING DIAGRAMS»(ref-133228) article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.

Scheme 68

Scheme 68
Scheme 68

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