SFI SYSTEM VC Output Circuit

DESCRIPTION

The ECM constantly generates a 5 V power source voltage from the battery voltage supplied to the +B, +B2 (BATT) terminals to operate the microprocessor. The ECM also provides this power to the sensors through the VC output circuit.

A0027U2E29

When the VC circuit has a short circuit, the microprocessor in the ECM and sensors that are supplied power through the VC circuit are deactivated because power is not supplied from the VC circuit. When the system is in this condition, it will not start.

WIRING DIAGRAM


CAUTION / NOTICE / HINT

Note

Check the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. CHECK CONNECTION BETWEEN GTS AND ECM


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      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

    B
    A
  2. CHECK EFI NO. 2 FUSE VOLTAGE

    A0028OSC01
    *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
    *2 EFI NO. 2 Fuse

    1. Turn the ignition switch to ON.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      1 (EFI NO. 2 fuse) - Body ground Ignition switch ON 11 to 14 V

      Tech Tips


      • Check the fuse with it installed to the No. 1 engine room relay block and No. 1 junction block assembly.

      • If the result is not as specified, since current is not flowing to the +B and +B2 terminals of the ECM, the system may not be started.

      Result
      Proceed to
      OK
      NG

    NG
    OK
  3. CHECK CONNECTION BETWEEN GTS AND ECM (THROTTLE POSITION SENSOR)


    1. Disconnect the throttle body with motor assembly connector.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      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

      Tech Tips

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

      Click here


    B
    A
  4. CHECK CONNECTION BETWEEN GTS AND ECM (ACCELERATOR PEDAL POSITION SENSOR)


    1. Disconnect the accelerator pedal sensor assembly connector.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      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

    B
    A
  5. CHECK CONNECTION BETWEEN GTS AND ECM (CRANKSHAFT POSITION SENSOR)


    1. Disconnect the crankshaft position sensor connector.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      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

    B
    A
  6. CHECK CONNECTION BETWEEN GTS 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 ignition switch to ON.

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      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

    B
    A
  7. CHECK CONNECTION BETWEEN GTS 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 ignition switch to ON.

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      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

    B
    A
  8. CHECK CONNECTION BETWEEN GTS 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 ignition switch to ON.

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      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

    B
    A
  9. CHECK CONNECTION BETWEEN GTS 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 ignition switch to ON.

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      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

    B
    A
  10. CHECK CONNECTION BETWEEN GTS AND ECM (FUEL PRESSURE SENSOR (FOR HIGH PRESSURE SIDE))


    1. Disconnect the fuel pressure sensor (for high pressure side) connector.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      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

      Tech Tips

      Perform "Inspection After Repair" after replacing the fuel pressure sensor (for high pressure side).

      Click here


    B
    A
  11. CHECK CONNECTION BETWEEN GTS AND ECM (FUEL PRESSURE SENSOR (FOR LOW PRESSURE SIDE))


    1. Disconnect the fuel pressure sensor (for low pressure side) connector.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      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

      Tech Tips

      Perform "Inspection After Repair" after replacing the fuel pressure sensor (for low pressure side).

      Click here


    B
    A
  12. CHECK CONNECTION BETWEEN GTS AND ECM (MASS AIR FLOW METER SUB-ASSEMBLY)


    1. Disconnect the mass air flow meter sub-assembly connector.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      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

      Tech Tips

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

      Click here


    B
    A
  13. CHECK HARNESS AND CONNECTOR


    1. Disconnect the throttle body with motor assembly connector.

    2. Disconnect the accelerator pedal sensor assembly connector.

    3. Disconnect the crankshaft position sensor connector.

    4. Disconnect the VVT sensor (for intake camshaft of bank 1) connector.

    5. Disconnect the VVT sensor (for intake camshaft of bank 2) connector.

    6. Disconnect the VVT sensor (for exhaust camshaft of bank 1) connector.

    7. Disconnect the VVT sensor (for exhaust camshaft of bank 2) connector.

    8. Disconnect the fuel pressure sensor (for high pressure side) connector.

    9. Disconnect the fuel pressure sensor (for low pressure side) connector.

    10. Disconnect the mass air flow meter sub-assembly connector.

    11. Disconnect the ECM connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      C1-121 (VCTA) - Body ground Always 10 kΩ or higher
      A43-49 (VCPA) - Body ground Always 10 kΩ or higher
      A43-52 (VCP2) - Body ground Always 10 kΩ or higher
      C1-96 (VCNE) - Body ground Always 10 kΩ or higher
      C1-99 (VCV1) - Body ground Always 10 kΩ or higher
      C1-98 (VCV2) - Body ground Always 10 kΩ or higher
      C1-90 (VC) - Body ground Always 10 kΩ or higher
      A43-2 (+B) - 1 (EFI NO. 2 fuse) Always Below 1 Ω
      A43-3 (+B2) - 1 (EFI NO. 2 fuse) Always Below 1 Ω
      A43-2 (+B) - Body ground Always 10 kΩ or higher
      A43-3 (+B2) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK
    NG