SFI SYSTEM VC Output Circuit

DESCRIPTION

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

A019MLSE01

When the VC circuit is shorted, the microprocessor in the ECM and sensors that are supplied with 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 engine switch is turned on (IG). The MIL turns off when the engine is started.

WIRING DIAGRAM

A019K4TE07
A019NCPE15

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK MIL


    1. Check that the Malfunction Indicator Lamp (MIL) turns on when turning the engine switch on (IG).

      OK
      MIL turns on.

    NG

    CHECK COMMUNICATION BETWEEN INTELLIGENT TESTER AND ECM Click here

    OK

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

  2. CHECK COMMUNICATION BETWEEN INTELLIGENT TESTER AND ECM


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the tester on.

    4. Check the 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 connector.

    2. Turn the engine switch on (IG).

    3. Check the MIL.

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

    4. Reconnect the throttle body connector.


    B

    REPLACE THROTTLE BODY Click here

    A

  4. CHECK MIL (ACCELERATOR PEDAL POSITION SENSOR)


    1. Disconnect the accelerator pedal position sensor connector.

    2. Turn the engine switch on (IG).

    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 SENSOR ASSEMBLY Click here

    A

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


    1. Disconnect the camshaft position sensor for intake side connector.

    2. Turn the engine switch on (IG).

    3. Check the MIL.

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

    4. Reconnect the camshaft position sensor for intake side connector.


    B

    REPLACE CAMSHAFT POSITION SENSOR (FOR INTAKE CAMSHAFT) Click here

    A

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


    1. Disconnect the camshaft position sensor for exhaust side connector.

    2. Turn the engine switch on (IG).

    3. Check the MIL.

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

    4. Reconnect the camshaft position sensor for exhaust side connector.


    B

    REPLACE CAMSHAFT POSITION SENSOR (FOR EXHAUST CAMSHAFT) Click here

    A

  7. CHECK MIL (INTAKE AIR CONTROL VALVE ACTUATOR FOR TUMBLE CONTROL VALVE)


    1. Disconnect the intake air control valve actuator connector.

    2. Turn the engine switch on (IG).

    3. Check the MIL.

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

    4. Reconnect the intake air control valve actuator connector.


    B

    REPLACE INTAKE AIR CONTROL VALVE ACTUATOR (FOR TUMBLE CONTROL VALVE) Click here

    A

  8. CHECK HARNESS AND CONNECTOR (VC CIRCUIT)


    1. Disconnect the throttle body connector.

    2. Disconnect the accelerator pedal position sensor connector.

    3. Disconnect the camshaft position sensor for intake side connector.

    4. Disconnect the camshaft position sensor for exhaust side connector.

    5. Disconnect the intake air control valve actuator connector.

    6. Disconnect the ECM connectors.

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

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A70-57 (VCPA) - Body ground Always 10 kΩ or higher
      A70-58 (VCP2) - Body ground Always 10 kΩ or higher
      D44-72 (VCIA) - Body ground Always 10 kΩ or higher
      D44-88 (VCTA) - Body ground Always 10 kΩ or higher
      D44-98 (VCE1) - Body ground Always 10 kΩ or higher
      D44-99 (VCV1) - Body ground Always 10 kΩ or higher

    8. Reconnect the throttle body connector.

    9. Reconnect the accelerator pedal position sensor connector.

    10. Reconnect the camshaft position sensor for intake side connector.

    11. Reconnect the camshaft position sensor for exhaust side connector.

    12. Reconnect the intake air control valve actuator connector.

    13. Reconnect the ECM connectors.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM Click here