SFI SYSTEM VC Output Circuit

DESCRIPTION

The ECM constantly generates 5 V power from the battery voltages supplied to the +B terminal and +B2 terminal to operate the microprocessor. The ECM also provides this power to the sensors through the VC output circuit.

A004IXRE04

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

WIRING DIAGRAM

A004HRSE05
A004KKUE07

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.
      Result
      Result Proceed to
      NG A
      OK B

    B

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

    A

  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 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 with motor 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

    B

    REPLACE THROTTLE WITH MOTOR BODY ASSEMBLY Click here

    A

  4. 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

    B

    REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR Click here

    A

  5. CHECK MIL (FUEL PRESSURE SENSOR)


    1. Disconnect the fuel 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 FUEL PRESSURE SENSOR Click here

    A

  6. 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

  7. CHECK MIL (BATTERY CURRENT SENSOR ASSEMBLY)


    1. Disconnect the battery current 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 BATTERY CURRENT SENSOR ASSEMBLY Click here

    A

  8. CHECK MIL (CANISTER PUMP MODULE)


    1. Disconnect the canister pump module 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 CANISTER PUMP MODULE Click here

    A

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


    1. Disconnect the throttle with motor body assembly connector.

    2. Disconnect the manifold absolute pressure sensor connector.

    3. Disconnect the fuel pressure sensor connector.

    4. Disconnect the accelerator pedal sensor assembly connector.

    5. Disconnect the battery current sensor assembly connector.

    6. Disconnect the canister pump module connector.

    7. Disconnect the ECM connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A36-19 (VC) - Body ground Always 10 kΩ or higher
      A35-22 (VCP2) - Body ground Always 10 kΩ or higher
      A35-21 (VCPA) - Body ground Always 10 kΩ or higher

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR