SFI SYSTEM VC Output Circuit

DESCRIPTION

The ECM constantly generates a 5 V power source 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.

A005JH3E03

When the VC circuit is short-circuited, the microprocessor in the ECM and the 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 to ON. The MIL goes off when the engine is started.

WIRING DIAGRAM

A005M5SE04
*a Throttle with Motor Body Assembly
*b Accelerator Pedal Sensor Assembly
*c Battery Current Sensor Assembly
A005KR6E03
*a Cam Position Sensor
*b Manifold Absolute Pressure Sensor
*c Oil Pressure 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

    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 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

      Tech Tips

      Perform "Inspection After Repairs" after replacing the throttle with motor body assembly Click here.


    B

    REPLACE THROTTLE WITH MOTOR 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 (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

  6. CHECK MIL (CAM POSITION SENSOR)


    1. Disconnect the cam position 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 CAM POSITION SENSOR

    A

  7. 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

    A

  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 does not illuminate A
      MIL illuminates B

    B

    REPLACE OIL PRESSURE SENSOR

    A

  9. CHECK HARNESS AND CONNECTOR


    1. Disconnect the throttle with motor body assembly connector.

    2. Disconnect the accelerator pedal sensor assembly connector.

    3. Disconnect the battery current sensor assembly connector.

    4. Disconnect the cam position sensor connector.

    5. Disconnect the manifold absolute pressure 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
      Tester Connection Condition Specified Condition
      B23-115 (VCTA) or B29-5 (VC) - Body ground Always 10 kΩ or higher
      A58-53 (VCPA) or A36-4 (VCPA) - Body ground Always 10 kΩ or higher
      A58-56 (VCP2) or A36-1 (VCP2) - Body ground Always 10 kΩ or higher
      A58-34 (VCIB) or A31-2 (VC5) - Body ground Always 10 kΩ or higher
      A23-113 (VCV1) or B32-3 (VC) - Body ground Always 10 kΩ or higher
      A23-118 (VCPM) or B35-3 (VC) - Body ground Always 10 kΩ or higher
      A23-120 (VCPT) or B45-3 (VC) - Body ground Always 10 kΩ or higher

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR