SFI SYSTEM VC Output Circuit

DESCRIPTION

The ECM constantly generates a 5 V power source voltage from the battery voltage supplied to the +B, +B2 (BATT) terminal to operate the microprocessor. The ECM also provides this power to the sensors through the VC output circuit.

A01T8Z2E36

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 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 when the ignition switch is turned ON. The MIL goes off when the engine is started.

WIRING DIAGRAM

A01TBDYE15

PROCEDURE


  1. CHECK MIL


    1. Check that the Malfunction Indicator Lamp (MIL) illuminates when the ignition switch is turned to ON.

      OK
      MIL illuminates.
      Result
      Proceed to
      OK
      NG

    OK

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

    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 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

      Tech Tips

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

      Click here


    B

    REPLACE THROTTLE BODY ASSEMBLY Click here

    A

  4. CHECK MIL (ACCELERATOR PEDAL SENSOR ASSEMBLY)


    1. Disconnect the accelerator pedal sensor 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

    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 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

    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 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

    B

    REPLACE CAMSHAFT POSITION SENSOR (FOR EXHAUST CAMSHAFT) Click here

    A

  7. 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 does not illuminate A
      MIL illuminates B

    B

    REPLACE OIL PRESSURE SENSOR Click here

    A

  8. CHECK HARNESS AND CONNECTOR


    1. Disconnect the throttle body assembly connector.

    2. Disconnect the accelerator pedal sensor assembly connector.

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

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

    5. Disconnect the oil pressure sensor connector.

    6. Disconnect the ECM connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B186-134 (VCTA) - Body ground Always 10 kΩ or higher
      A50-49 (VCPA) - Body ground Always 10 kΩ or higher
      A50-52 (VCP2) - Body ground Always 10 kΩ or higher
      B186-116 (VCV1) - Body ground Always 10 kΩ or higher
      B186-111 (VCE1) - Body ground Always 10 kΩ or higher
      B186-110 (VCPT) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR