SFI SYSTEM (w/ EGR System) VC Output Circuit

DESCRIPTION

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

A003XJTE18

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

WIRING DIAGRAM

A003VSOE04

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK MIL


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

      OK
      MIL lights up.

    NG

    CHECK CONNECTION BETWEEN INTELLIGENT TESTER AND ECM Click here

    OK

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

  2. CHECK CONNECTION BETWEEN INTELLIGENT TESTER AND ECM


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

    4. Check the communication between the intelligent 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 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


    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 D27-88 (VCTA) - Body ground Always 10 kΩ or higher
      D18-3 (VC) or D27-99 (VCV1) - Body ground Always 10 kΩ or higher
      D3-3 (VC) or D27-72 (VCPM) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM Click here