SFI SYSTEM VC Output Circuit

DESCRIPTION

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

A005714E01

When the VC circuit is short-circuited, 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 ignition switch is first turned to ON. The MIL goes off when the engine is started.

WIRING DIAGRAM

A0053VFE09
*a Camshaft Position Sensor (for Intake Side)
*b Camshaft Position Sensor (for Exhaust Side)
*c Vacuum Sensor
*d Oil Pressure Sensor
A005993E02
*a Throttle Position Sensor
*b Accelerator Pedal Position Sensor

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.

    OK

    SYSTEM OK

    NG

  2. 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 for communication between the GTS 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 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 illuminates A
      MIL does not illuminate B

      Tech Tips

      Perform "Inspection After Repair" after replacing the throttle body assembly Click here.

    4. Reconnect the throttle body assembly connector.


    A

    REPLACE THROTTLE BODY ASSEMBLY Click here

    B

  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 illuminates A
      MIL does not illuminate B

    4. Reconnect the accelerator pedal position sensor connector.


    A

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

    B

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


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

    2. Turn the ignition switch to ON.

    3. Check the MIL.

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

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


    A

    REPLACE CAMSHAFT POSITION SENSOR (FOR INTAKE SIDE) Click here

    B

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


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

    2. Turn the ignition switch to ON.

    3. Check the MIL.

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

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


    A

    REPLACE CAMSHAFT POSITION SENSOR (FOR EXHAUST SIDE) Click here

    B

  7. CHECK MIL (VACUUM SENSOR)


    1. Disconnect the vacuum sensor connector.

    2. Turn the ignition switch to ON.

    3. Check the MIL.

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

    4. Reconnect the vacuum sensor connector.


    A

    REPLACE VACUUM SENSOR Click here

    B

  8. CHECK MIL (OIL PRESSURE SENSOR)


    1. Disconnect the oil pressure sensor connector.

    2. Turn the ignition switch to ON.

    3. Check the MIL.

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

    4. Reconnect the oil pressure sensor connector.


    A

    REPLACE OIL PRESSURE SENSOR Click here

    B

  9. CHECK HARNESS AND CONNECTOR


    1. Disconnect the throttle body assembly connector.

    2. Disconnect the accelerator pedal position sensor connector.

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

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

    5. Disconnect the vacuum sensor connector.

    6. Disconnect the oil pressure 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
      B53-134 (VCTA) - Body ground Always 10 kΩ or higher
      A67-49 (VCPA) - Body ground Always 10 kΩ or higher
      A67-52 (VCP2) - Body ground Always 10 kΩ or higher
      B53-116 (VCV1) - Body ground Always 10 kΩ or higher
      B53-111 (VCE1) - Body ground Always 10 kΩ or higher
      B53-77 (VCPM) - Body ground Always 10 kΩ or higher
      B53-110 (VCPT) - 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 camshaft position sensor (for intake camshaft) connector.

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

    13. Reconnect the vacuum sensor connector.

    14. Reconnect the oil pressure sensor connector.

    15. Reconnect the ECM connectors.


    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR