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Home >> Lexus >> 2017 >> GX 460 Base >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Control System (Diagnostic Codes) (3 Of 7) >> SFI System >> DTC P0403: Exhaust Gas Recirculation Control Circuit [08/2015 - 08/2022] >> Procedure
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DTC P0403: Exhaust Gas Recirculation Control Circuit [08/2015 - 08/2022]: Procedure

  1. PERFORM ACTIVE TEST USING TECHSTREAM (OPERATE EGR VALVE) 
    1. Connect the Techstream to the DLC3.
    2. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

      HINT: 

      • When performing the Active Test, make sure the shift lever is in P or N.
      • The A/C switch and all accessory switches should be off.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position.
    5. Confirm that Throttle Idle Position is ON and check the engine idling condition and the value of MAP in the Data List while performing the Active Test.

      HINT: 

      • Do not leave the EGR valve open for 10 seconds or more during the Active Test.
      • Be sure to return the EGR valve to step 0 when the Active Test is completed.

      OK

      MAP and idling condition change in response to EGR step position as follows.

      Standard

      - EGR Step Position (Active Test)
      Step 0 Step 0 to 30
      Idling condition Steady idling Idling changes from steady to rough idling or engine stalls
      MAP
      (Data List)      		 20 to 40 kPa (150 to 300 mmHg) MAP value is at least 10 kPa (75 mmHg) higher than when EGR valve is fully closed

    Result: 

    OK 

    CHECK FOR INTERMITTENT PROBLEMS 

    (Refer to CHECK FOR INTERMITTENT PROBLEMS [08/2015 - ] )

    Result: 

    NG 

    See step  2

  2. INSPECT EGR VALVE ASSEMBLY 
    1. Inspect the EGR valve assembly (Refer to PROCEDURE - Step 1 ).

      HINT: 

      Perform "Inspection After Repairs" after replacing the EGR valve assembly (Refer to INITIALIZATION [08/2015 - ] ).

    Result: 

    NG 

    REPLACE EGR VALVE ASSEMBLY 

    (Refer to REMOVAL [08/2015 - ] )

    Result: 

    OK 

    See step  3

  3. INSPECT EGR VALVE ASSEMBLY (+B OR +B2 VOLTAGE) 
    GTY674892Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the EGR valve assembly connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      C43-5 (+B1) - Body ground Engine switch on (IG) 11 to 14 V
      C43-2 (+B2) - Body ground Engine switch on (IG) 11 to 14 V
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to EGR Valve Assembly)
    3. Reconnect the EGR valve assembly connector.

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (ECM - EGR VALVE ASSEMBLY) 
    1. Disconnect the EGR valve assembly connector.
    2. Disconnect the ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      C28-23 (EGR1) - C43-4 (EGR1) Always Below 1 Ω
      C28-36 (EGR2) - C43-3 (EGR2) Always Below 1 Ω
      C28-30 (EGR3) - C43-6 (EGR3) Always Below 1 Ω
      C28-24 (EGR4) - C43-1 (EGR4) Always Below 1 Ω
      C28-23 (EGR1) or C43-4 (EGR1) - Body ground Always 10 kΩ or higher
      C28-36 (EGR2) or C43-3 (EGR2) - Body ground Always 10 kΩ or higher
      C28-30 (EGR3) or C43-6 (EGR3) - Body ground Always 10 kΩ or higher
      C28-24 (EGR4) or C43-1 (EGR4) - Body ground Always 10 kΩ or higher
    4. Reconnect the EGR valve assembly connector.
    5. Reconnect the ECM connector.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. CHECK WHETHER DTC OUTPUT RECURS (DTC P0403) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG) and turn the Techstream on.
    3. Clear the DTCs (Refer to DTC CHECK / CLEAR [08/2015 - ] ).
    4. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    5. Confirm that no DTC is output using the Techstream.
      RESULT

      Result Proceed to
      P0403 output A
      No output B

    Result: 

    A 

    REPLACE ECM 

    (Refer to REMOVAL [08/2015 - ] )

    Result: 

    B 

    END 

  6. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - EGR VALVE ASSEMBLY) 
    1. Disconnect the EGR valve assembly connector.
    2. Remove the No. 1 integration relay from engine room relay block.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1B-4 - C43-5 (+B1) Always Below 1 Ω
      1B-4 - C43-2 (+B2) Always Below 1 Ω
      1B-4 or C43-5 (+B1) - Body ground Always 10 kΩ or higher
      1B-4 or C43-2 (+B2) - Body ground Always 10 kΩ or higher
    4. Reconnect the EGR valve assembly connector.
    5. Reinstall the No. 1 integration relay.

    Result: 

    OK 

    CHECK ECM POWER SOURCE CIRCUIT 

    (Refer to ECM Power Source Circuit [08/2015 - 08/2019] , or refer to ECM Power Source Circuit [08/2019 - ] )

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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