SFI SYSTEM VC Output Circuit

DESCRIPTION

The ECM constantly generates 5 V power 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.

A011BGLE01

When the VC circuit is short-circuited, the microprocessor in the ECM and sensors that are supplied with power through the VC circuit are deactivated 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 ON. The MIL goes off when the engine is started.

WIRING DIAGRAM

A01197DE19
A011AKHE01

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK MIL CONDITION


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

      OK
      MIL lights up.

    NG

    CHECK CONNECTION BETWEEN INTELLIGENT TESTER AND ECM Click here

    OK

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

  2. CHECK CONNECTION BETWEEN INTELLIGENT TESTER AND ECM


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Check for communication between the tester and ECM.

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

    B

    GO TO MIL CIRCUIT Click here

    A

  3. CHECK MIL (THROTTLE POSITION SENSOR)


    1. Disconnect the throttle body assembly connector.

    2. Turn the ignition switch to ON.

    3. Check the MIL.

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

    4. Reconnect the throttle body assembly connector.


    B

    REPLACE THROTTLE BODY ASSEMBLY Click here

    A

  4. CHECK MIL (ACCELERATOR PEDAL POSITION SENSOR)


    1. Disconnect the accelerator pedal position sensor connector.

    2. Turn the ignition switch to ON.

    3. Check the MIL.

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

    4. Reconnect the accelerator pedal position sensor connector.


    B

    REPLACE ACCELERATOR PEDAL ASSEMBLY (ACCELERATOR PEDAL POSITION SENSOR) Click here

    A

  5. CHECK MIL (MANIFOLD ABSOLUTE PRESSURE SENSOR)


    1. Disconnect the manifold absolute pressure sensor connector.

    2. Turn the ignition switch to ON.

    3. Check the MIL.

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

    4. Reconnect the manifold absolute pressure sensor connector.


    B

    REPLACE THE MANIFOLD ABSOLUTE PRESSURE SENSOR Click here

    A

  6. CHECK MIL (CAMSHAFT POSITION SENSOR (FOR INTAKE CAMSHAFT))


    1. Disconnect the camshaft position sensor (for intake camshaft) connector.

    2. Turn the ignition switch to ON.

    3. Check the MIL.

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

    4. Reconnect the camshaft position sensor (for intake camshaft) connector.


    B

    REPLACE CAMSHAFT POSITION SENSOR (FOR INTAKE CAMSHAFT) Click here

    A

  7. CHECK MIL (CAMSHAFT POSITION SENSOR (FOR EXHAUST CAMSHAFT))


    1. Disconnect the camshaft position sensor (for exhaust camshaft) connector.

    2. Turn the ignition switch to ON.

    3. Check the MIL.

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

    4. Reconnect the camshaft position sensor (for exhaust camshaft) connector.


    B

    REPLACE CAMSHAFT POSITION SENSOR (FOR EXHAUST CAMSHAFT) Click here

    A

  8. CHECK MIL (CRANKSHAFT POSITION SENSOR)


    1. Disconnect the crankshaft position sensor connector.

    2. Turn the ignition switch to ON.

    3. Check the MIL.

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

    4. Reconnect the crankshaft position sensor connector.


    B

    REPLACE CRANKSHAFT POSITION SENSOR Click here

    A

  9. CHECK HARNESS AND CONNECTOR (EACH SENSOR - ECM)


    1. Disconnect the throttle body assembly connector.

    2. Disconnect the accelerator pedal position sensor connector.

    3. Disconnect the manifold absolute sensor connector.

    4. Disconnect the camshaft position sensor (for intake camshaft) connector.

    5. Disconnect the camshaft position sensor (for exhaust camshaft) connector.

    6. Disconnect the crankshaft position sensor 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 Connection Condition Specified Condition
      B8-89 (VCTA) - Body ground Always 10 kΩ or higher
      A18-57 (VCPA) - Body ground Always 10 kΩ or higher
      A18-58 (VCP2) - Body ground Always 10 kΩ or higher
      B8-67 (VCPM) - Body ground Always 10 kΩ or higher
      B8-119 (VCV1) - Body ground Always 10 kΩ or higher
      B8-121 (VCE1) - Body ground Always 10 kΩ or higher
      B8-116 (VCNE) - Body ground Always 10 kΩ or higher

    9. Reconnect the throttle body assembly connector.

    10. Reconnect the accelerator pedal position sensor connector.

    11. Reconnect the manifold absolute sensor connector.

    12. Reconnect the camshaft position sensor (for intake camshaft) connector.

    13. Reconnect the camshaft position sensor (for exhaust camshaft) connector.

    14. Reconnect the crankshaft position sensor connector.

    15. Reconnect the ECM connectors.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM Click here