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Home >> Lexus >> 2018 >> LC 500 >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System - Diagnostic Codes (Coupe) (7 Of 7) & Circuit Tests (1 Of 2) >> SFI System >> VC Output Circuit [03/2017 - 05/2023] >> Procedure

VC Output Circuit [03/2017 - 05/2023]: Procedure

  1. READ VALUE USING TECHSTREAM 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Check the communication between the Techstream and ECM.

      HINT: 

      It can be checked using the "Engine" item of the Data List.

      Result

      Result Proceed to
      Communication is not possible A
      Communication is possible B

    Result: 

    B 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [03/2017 - 09/2018]  , or refer to  PROBLEM SYMPTOMS TABLE [09/2018 - ] 

    Result: 

    A 

    See step  2

  2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF ECM) 
    1. Turn the engine switch on (IG).
    2. Measure the voltage according to the value(s) in the table below.
      GTY797501Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and Junction Block Assembly
      *2 EFI NO. 1 Fuse

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      1 (EFI NO. 1 fuse)- Body ground Engine switch on (IG) 11 to 14 V

      HINT: 

      • Check the fuse with it installed to the No. 1 engine room relay block and junction block assembly.
      • If the result is not as specified, since current is not flowing to the +B and +B2 terminals of the ECM assembly, the system may not be started.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO ECM POWER SOURCE CIRCUIT. Refer to  ECM Power Source Circuit [03/2017 - 05/2023]  

    Result: 

    OK 

    See step  3

  3. CHECK CONNECTION BETWEEN TECHSTREAM AND ECM (THROTTLE POSITION SENSOR) 
    1. Disconnect the throttle body with motor assembly connector.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Check the communication between the Techstream and ECM.

      HINT: 

      It can be checked using the "Engine" item of the Data List.

      Result

      Result Proceed to
      Communication is not possible A
      Communication is possible B

      HINT: 

      Perform "Inspection After Repair" after replacing the throttle body with motor assembly.

      Refer to INITIALIZATION [03/2017 - ]

    Result: 

    B 

    REPLACE THROTTLE BODY WITH MOTOR ASSEMBLY. Refer to  REMOVAL [03/2017 - ] 

    Result: 

    A 

    See step  4

  4. CHECK CONNECTION BETWEEN TECHSTREAM AND ECM (ACCELERATOR PEDAL SENSOR) 
    1. Disconnect the accelerator pedal sensor assembly connector.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Check the communication between the Techstream and ECM.

      HINT: 

      It can be checked using the "Engine" item of the Data List.

      Result

      Result Proceed to
      Communication is not possible A
      Communication is possible B

    Result: 

    B 

    REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY. Refer to  REMOVAL [03/2017 - ] 

    Result: 

    A 

    See step  5

  5. CHECK CONNECTION BETWEEN TECHSTREAM AND ECM (MASS AIR FLOW METER SUB-ASSEMBLY (BANK 1)) 
    1. Disconnect the mass air flow meter sub-assembly (bank 1) connector.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Check the communication between the Techstream and ECM.

      HINT: 

      It can be checked using the "Engine" item of the Data List.

      Result

      Result Proceed to
      Communication is not possible A
      Communication is possible B

      HINT: 

      Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly.

      Refer to INITIALIZATION [03/2017 - ]

    Result: 

    B 

    REPLACE MASS AIR FLOW METER SUB-ASSEMBLY (BANK 1). Refer to  REMOVAL [03/2017 - ] 

    Result: 

    A 

    See step  6

  6. CHECK CONNECTION BETWEEN TECHSTREAM AND ECM (MASS AIR FLOW METER SUB-ASSEMBLY (BANK 2)) 
    1. Disconnect the mass air flow meter sub-assembly (bank 2) connector.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Check the communication between the Techstream and ECM.

      HINT: 

      It can be checked using the "Engine" item of the Data List.

      Result

      Result Proceed to
      Communication is not possible A
      Communication is possible B

      HINT: 

      Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly.

      Refer to INITIALIZATION [03/2017 - ]

    Result: 

    B 

    REPLACE MASS AIR FLOW METER SUB-ASSEMBLY (BANK 2). Refer to  REMOVAL [03/2017 - ] 

    Result: 

    A 

    See step  7

  7. CHECK CONNECTION BETWEEN TECHSTREAM AND ECM (FUEL DELIVERY PIPE LH (FUEL PRESSURE SENSOR)) 
    1. Disconnect the fuel delivery pipe LH (fuel pressure sensor).
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Check the communication between the Techstream and ECM.

      HINT: 

      It can be checked using the "Engine" item of the Data List.

      Result

      Result Proceed to
      Communication is not possible A
      Communication is possible B

    Result: 

    B 

    REPLACE FUEL DELIVERY PIPE SUB-ASSEMBLY (FUEL PRESSURE SENSOR). Refer to  REMOVAL [03/2017 - 05/2023] 

    Result: 

    A 

    See step  8

  8. CHECK CONNECTION BETWEEN TECHSTREAM AND ECM (VVT SENSOR (FOR INTAKE CAMSHAFT OF BANK 1)) 
    1. Disconnect the VVT sensor (for intake camshaft of bank 1) connector.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Check the communication between the Techstream and ECM.

      HINT: 

      It can be checked using the "Engine" item of the Data List.

      Result

      Result Proceed to
      Communication is not possible A
      Communication is possible B

    Result: 

    B 

    REPLACE VVT SENSOR (FOR INTAKE CAMSHAFT OF BANK 1). Refer to  REMOVAL [03/2017 - ] 

    Result: 

    A 

    See step  9

  9. CHECK CONNECTION BETWEEN TECHSTREAM AND ECM (VVT SENSOR (FOR INTAKE CAMSHAFT OF BANK 2)) 
    1. Disconnect the VVT sensor (for intake camshaft of bank 2) connector.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Check the communication between the Techstream and ECM.

      HINT: 

      It can be checked using the "Engine" item of the Data List.

      Result

      Result Proceed to
      Communication is not possible A
      Communication is possible B

    Result: 

    B 

    REPLACE VVT SENSOR (FOR INTAKE CAMSHAFT OF BANK 2). Refer to  REMOVAL [03/2017 - ] 

    Result: 

    A 

    See step  10

  10. CHECK CONNECTION BETWEEN TECHSTREAM AND ECM (VVT SENSOR (FOR EXHAUST CAMSHAFT OF BANK 1)) 
    1. Disconnect the VVT sensor (for exhaust camshaft of bank 1) connector.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Check the communication between the Techstream and ECM.

      HINT: 

      It can be checked using the "Engine" item of the Data List.

      Result

      Result Proceed to
      Communication is not possible A
      Communication is possible B

    Result: 

    B 

    REPLACE VVT SENSOR (FOR EXHAUST CAMSHAFT OF BANK 1). Refer to  REMOVAL [03/2017 - ] 

    Result: 

    A 

    See step  11

  11. CHECK CONNECTION BETWEEN TECHSTREAM AND ECM (VVT SENSOR (FOR EXHAUST CAMSHAFT OF BANK 2)) 
    1. Disconnect the VVT sensor (for exhaust camshaft of bank 2) connector.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Check the communication between the Techstream and ECM.

      HINT: 

      It can be checked using the "Engine" item of the Data List.

      Result

      Result Proceed to
      Communication is not possible A
      Communication is possible B

    Result: 

    B 

    REPLACE VVT SENSOR (FOR EXHAUST CAMSHAFT OF BANK 2). Refer to  REMOVAL [03/2017 - ] 

    Result: 

    A 

    See step  12

  12. CHECK CONNECTION BETWEEN TECHSTREAM AND ECM (CAMSHAFT POSITION SENSOR) 
    1. Disconnect the camshaft position sensor connector.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Check the communication between the Techstream and ECM.

      HINT: 

      It can be checked using the "Engine" item of the Data List.

      Result

      Result Proceed to
      Communication is not possible A
      Communication is possible B

    Result: 

    B 

    REPLACE CAMSHAFT POSITION SENSOR. Refer to  REMOVAL [03/2017 - ] 

    Result: 

    A 

    See step  13

  13. CHECK CONNECTION BETWEEN TECHSTREAM AND ECM (CRANKSHAFT POSITION SENSOR) 
    1. Disconnect the c1 crankshaft position sensor connector.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Check the communication between the Techstream and ECM.

      HINT: 

      It can be checked using the "Engine" item of the Data List.

      Result

      Result Proceed to
      Communication is not possible A
      Communication is possible B

    Result: 

    B 

    REPLACE CRANKSHAFT POSITION SENSOR. Refer to  REMOVAL [03/2017 - 09/2023] 

    Result: 

    A 

    See step  14

  14. CHECK CONNECTION BETWEEN TECHSTREAM AND ECM (CANISTER PUMP MODULE) 
    1. Disconnect the canister pump module connector.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Check the communication between the Techstream and ECM.

      HINT: 

      It can be checked using the "Engine" item of the Data List.

      Result

      Result Proceed to
      Communication is not possible A
      Communication is possible B

    Result: 

    B 

    REPLACE CANISTER PUMP MODULE. Refer to  REMOVAL [03/2017 - ] 

    Result: 

    A 

    See step  15

  15. CHECK HARNESS AND CONNECTOR 
    1. Disconnect the throttle body with motor assembly connector.
    2. Disconnect the accelerator pedal sensor assembly connector.
    3. Disconnect the mass air flow meter sub-assembly (bank 1) connector.
    4. Disconnect the mass air flow meter sub-assembly (bank 2) connector.
    5. Disconnect the fuel delivery pipe LH (fuel pressure sensor).
    6. Disconnect the VVT sensor (for intake camshaft of bank 1) connector.
    7. Disconnect the VVT sensor (for intake camshaft of bank 2) connector.
    8. Disconnect the VVT sensor (for exhaust camshaft of bank 1) connector.
    9. Disconnect the VVT sensor (for exhaust camshaft of bank 2) connector.
    10. Disconnect the camshaft position sensor connector.
    11. Disconnect the crankshaft position sensor connector.
    12. Disconnect the canister pump module connector.
    13. Disconnect the ECM connectors.
    14. Remove the A/F HTR relay from the No. 1 engine room relay block and junction block assembly.

      HINT: 

      Remove the A/F HTR relay connected between the checked terminals as the coil inside the relay influences the measurement value.

    15. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G42-90 (VC) - Body ground and other terminals Always 10 kΩ or higher
      G42-121 (VCTA) - Body ground and other terminals Always 10 kΩ or higher
      A58-49 (VCPA) - Body ground and other terminals Always 10 kΩ or higher
      A58-52 (VCP2) - Body ground and other terminals Always 10 kΩ or higher
      A58-39 (VCVG) - Body ground and other terminals Always 10 kΩ or higher
      A58-56 (VCCR) - Body ground and other terminals Always 10 kΩ or higher
      G42-128 (VCPR) - Body ground and other terminals Always 10 kΩ or higher
      1 (EFI NO. 1 fuse) - A58-2 (+B) Always Below 1 Ω
      1 (EFI NO. 1 fuse) - A58-3 (+B2) Always Below 1 Ω
      A58-2 (+B) - Body ground and other terminals Always 10 kΩ or higher
      A58-3 (+B2) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [03/2017 - 05/2023] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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