SFI SYSTEM VC Output Circuit

DESCRIPTION

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

A005EYRE11

When the VC circuit is shorted, the microprocessor in the ECM and sensors that are supplied 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 power switch is turned on (IG). The MIL goes off when the power switch is turned on (READY).

WIRING DIAGRAM

A005F09E06
*a Throttle Body Assembly
*b Camshaft Position Sensor
*c Manifold Absolute Pressure Sensor

PROCEDURE


  1. CHECK MIL


    1. Check that the Malfunction Indicator Lamp (MIL) illuminates when turning the power switch on (IG).

      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 power switch on (IG).

    3. Turn the GTS on.

    4. Check the 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 position sensor connector.

    2. Turn the power switch on (IG).

    3. Check the MIL.

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

    B

    REPLACE THROTTLE BODY ASSEMBLY Click here

    A

  4. CHECK MIL (CAMSHAFT POSITION SENSOR)


    1. Disconnect the camshaft position sensor connector.

    2. Turn the power switch on (IG).

    3. Check the MIL.

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

    B

    REPLACE CAMSHAFT POSITION SENSOR Click here

    A

  5. CHECK MIL (MANIFOLD ABSOLUTE PRESSURE SENSOR)


    1. Disconnect the manifold absolute pressure sensor connector.

    2. Turn the power switch on (IG).

    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

  6. CHECK HARNESS AND CONNECTOR (THROTTLE POSITION SENSOR - ECM)


    1. Disconnect the throttle position sensor connector.

    2. Disconnect the camshaft position sensor connector.

    3. Disconnect the manifold absolute pressure sensor connector.

    4. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D4-5 (VC) or D28-88 (VCTA) - Body ground Always 10 kΩ or higher
      D18-3 (VC) or D28-99 (VCV1) - Body ground Always 10 kΩ or higher
      D3-3 (VC) or D28-72 (VCPM) - Body ground Always 10 kΩ or higher

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR