SFI SYSTEM VC Output Circuit

DESCRIPTION

The ECM constantly uses 5 V from the battery voltages supplied to the +B (BATT) terminal to operate the microprocessor. The ECM also provides this power to the sensors through the VC output circuit.

When the VC circuit is short-circuited, the microprocessor in the ECM and sensors that are supplied power through the VC circuit are inactivated because the power is not supplied from the VC circuit. Under this condition, the system does not start up and the MIL does not illuminate even if the system malfunctions.

Tech Tips

Under normal conditions, the MIL is illuminated for several seconds when the ignition switch is first turned to the on (IG). The MIL goes off when the engine is started.

A017DEHE36

WIRING DIAGRAM

A017EPAE01
A017F5FE08

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK MIL


    1. Check that the Malfunction Indicator Lamp (MIL) lights up when turning the ignition switch on (IG).

      OK
      MIL lights up.

    NG

    CHECK CONNECTION BETWEEN INTELLIGENT TESTER AND ECM Click here

    OK

    GO TO MIL CIRCUIT Click here

  2. CHECK CONNECTION BETWEEN INTELLIGENT TESTER AND ECM


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch on (IG) and turn the tester on.

    3. Check the communication between the tester and ECM.

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

    A

    GO TO MIL CIRCUIT Click here

    B

  3. CHECK THROTTLE BODY (CHECK MIL ILLUMINATED)


    1. Disconnect the throttle body connector.

    2. Turn the ignition switch on (IG).

    3. Check the MIL.

      Result
      Result Proceed to
      MIL illuminates A
      MIL does not illuminate B

    4. Reconnect the throttle body connector.


    A

    REPLACE THROTTLE BODY Click here

    B

  4. CHECK ACCELERATOR PEDAL ROD (CHECK MIL ILLUMINATED)


    1. Disconnect the accelerator pedal position sensor connector.

    2. Turn the ignition switch on (IG).

    3. Check the MIL.

      Result
      Result Proceed to
      MIL illuminates A
      MIL does not illuminate B

    4. Reconnect the accelerator pedal position sensor connector.


    A

    REPLACE ACCELERATOR PEDAL ROD Click here

    B

  5. CHECK VVT SENSOR FOR INTAKE CAMSHAFT BANK 1 (CHECK MIL ILLUMINATED)


    1. Disconnect the VVT sensor for intake camshaft bank 1 connector.

    2. Turn the ignition switch on (IG).

    3. Check the MIL.

      Result
      Result Proceed to
      MIL illuminates A
      MIL does not illuminate B

    4. Reconnect the VVT sensor for intake camshaft bank 1 connector.


    A

    REPLACE VVT SENSOR FOR INTAKE CAMSHAFT BANK 1 Click here

    B

  6. CHECK VVT SENSOR FOR EXHAUST CAMSHAFT BANK 1 (CHECK MIL ILLUMINATED)


    1. Disconnect the VVT sensor for exhaust camshaft bank 1 connector.

    2. Turn the ignition switch on (IG).

    3. Check the MIL.

      Result
      Result Proceed to
      MIL illuminates A
      MIL does not illuminate B

    4. Reconnect the VVT sensor for exhaust camshaft bank 1 connector.


    A

    REPLACE VVT SENSOR FOR EXHAUST CAMSHAFT BANK 1 Click here

    B

  7. CHECK VVT SENSOR FOR INTAKE CAMSHAFT BANK 2 (CHECK MIL ILLUMINATED)


    1. Disconnect the VVT sensor for intake camshaft bank 2 connector.

    2. Turn the ignition switch on (IG).

    3. Check the MIL.

      Result
      Result Proceed to
      MIL illuminates A
      MIL does not illuminate B

    4. Reconnect the VVT sensor for intake camshaft bank 2 connector.


    A

    REPLACE VVT SENSOR FOR INTAKE CAMSHAFT BANK 2 Click here

    B

  8. CHECK VVT SENSOR FOR EXHAUST CAMSHAFT BANK 2 (CHECK MIL ILLUMINATED)


    1. Disconnect the VVT sensor for exhaust camshaft bank 2 connector.

    2. Turn the ignition switch on (IG).

    3. Check the MIL.

      Result
      Result Proceed to
      MIL illuminates A
      MIL does not illuminate B

    4. Reconnect the VVT sensor for exhaust camshaft bank 2 connector.


    A

    REPLACE VVT SENSOR FOR EXHAUST CAMSHAFT BANK 2 Click here

    B

  9. CHECK HARNESS AND CONNECTOR


    1. A017CKHE03

      Disconnect the throttle body connector.

    2. Disconnect the accelerator pedal position sensor connector.

    3. Disconnect the VVT sensor for intake camshaft bank 1 connector.

    4. Disconnect the VVT sensor for exhaust camshaft bank 1 connector.

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

    6. Disconnect the VVT sensor for exhaust camshaft bank 2 connector.

    7. Disconnect the ECM connectors.

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

      Standard resistance (Check for short)
      Tester Connections Specified Conditions
      VC (B1-23) - Body ground 10 kΩ or higher
      VCPA (D31-26) - Body ground 10 kΩ or higher
      VCP2 (D31-27) - Body ground 10 kΩ or higher

    9. Reconnect the ECM connectors.

    10. Reconnect the VVT sensor for exhaust camshaft bank 2 connector.

    11. Reconnect the VVT sensor for intake camshaft bank 2 connector.

    12. Reconnect the VVT sensor for exhaust camshaft bank 1 connector.

    13. Reconnect the VVT sensor for intake camshaft bank 1 connector.

    14. Reconnect the accelerator pedal position sensor connector.

    15. Reconnect the throttle body connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM Click here