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.

A005714E80

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, and then goes off when the engine starts.

WIRING DIAGRAM

A0058FLE52
*a Throttle Position Sensor
*b Accelerator Pedal Position Sensor
*c Camshaft Position Sensor (Intake Side)
*d Camshaft Position Sensor (Exhaust Side)

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 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 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 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

    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 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 illuminates A
      MIL does not illuminate B

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


    A

    REPLACE CAMSHAFT POSITION SENSOR (FOR INTAKE CAMSHAFT) Click here

    B

  6. 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 illuminates A
      MIL does not illuminate B

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


    A

    REPLACE CAMSHAFT POSITION SENSOR (FOR EXHAUST CAMSHAFT) Click here

    B

  7. 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 ECM connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B39-89 (VCTA) - Body ground Always 10 kΩ or higher
      A40-57 (VCPA) - Body ground Always 10 kΩ or higher
      A40-58 (VCP2) - Body ground Always 10 kΩ or higher
      B39-119 (VCV1) - Body ground Always 10 kΩ or higher
      B39-121 (VCE1) - Body ground Always 10 kΩ or higher

    7. Reconnect the throttle body assembly connector.

    8. Reconnect the accelerator pedal position sensor connector.

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

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

    11. Reconnect the ECM connectors.


    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR