SFI 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.

A01FUD8E41

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

A01FRE6E02
A01FRK2E01

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK MIL


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

      OK
      MIL lights up.

    NG

    CHECK CONNECTION BETWEEN GTS AND ECM Click here

    OK

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

  2. CHECK CONNECTION BETWEEN GTS AND ECM


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG) and GTS on.

    3. 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 body with motor connector.

    2. Turn the power switch on (IG).

    3. Check the MIL.

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

    4. Reconnect the throttle body with motor connector.

      Tech Tips

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


    B

    REPLACE THROTTLE BODY WITH MOTOR ASSEMBLY Click here

    A

  4. 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

    4. Reconnect the manifold absolute pressure sensor connector.


    B

    REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR Click here

    A

  5. CHECK MIL (VVT SENSOR FOR INTAKE CAMSHAFT BANK 1)


    1. Disconnect the VVT sensor for intake camshaft bank 1 connector.

    2. Turn the power switch on (IG).

    3. Check the MIL.

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

    4. Reconnect the VVT sensor for intake camshaft bank 1 connector.


    B

    REPLACE VVT SENSOR FOR INTAKE CAMSHAFT BANK 1 Click here

    A

  6. CHECK MIL (VVT SENSOR FOR EXHAUST CAMSHAFT BANK 1)


    1. Disconnect the VVT sensor for exhaust camshaft bank 1 connector.

    2. Turn the power switch on (IG).

    3. Check the MIL.

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

    4. Reconnect the VVT sensor for exhaust camshaft bank 1 connector.


    B

    REPLACE VVT SENSOR FOR EXHAUST CAMSHAFT BANK 1 Click here

    A

  7. CHECK MIL (VVT SENSOR FOR INTAKE CAMSHAFT BANK 2)


    1. Disconnect the VVT sensor for intake camshaft bank 2 connector.

    2. Turn the power switch on (IG).

    3. Check the MIL.

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

    4. Reconnect the VVT sensor for intake camshaft bank 2 connector.


    B

    REPLACE VVT SENSOR FOR INTAKE CAMSHAFT BANK 2 Click here

    A

  8. CHECK MIL (VVT SENSOR FOR EXHAUST CAMSHAFT BANK 2)


    1. Disconnect the VVT sensor for exhaust camshaft bank 2 connector.

    2. Turn the power switch on (IG).

    3. Check the MIL.

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

    4. Reconnect the VVT sensor for exhaust camshaft bank 2 connector.


    B

    REPLACE VVT SENSOR FOR EXHAUST CAMSHAFT BANK 2 Click here

    A

  9. CHECK MIL (FUEL PRESSURE SENSOR)


    1. Disconnect the fuel 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

    4. Reconnect the fuel pressure sensor connector.


    B

    REPLACE FUEL PRESSURE SENSOR Click here

    A

  10. CHECK MIL (CANISTER PUMP MODULE)


    1. Disconnect the canister pump module connector.

    2. Turn the power switch on (IG).

    3. Check the MIL.

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

    4. Reconnect the canister pump module connector.


    B

    REPLACE LEAK DETECTION PUMP SUB-ASSEMBLY Click here

    A

  11. CHECK HARNESS AND CONNECTOR


    1. Disconnect the throttle body with motor connector.

    2. Disconnect the manifold absolute pressure sensor connector.

    3. Disconnect the VVT sensor for intake camshaft bank 1 connector.

    4. Disconnect the VVT sensor for exhaust camshaft bank 1 connector.

    5. Disconnect the VVT sensor for intake camshaft bank 2 connector.

    6. Disconnect the VVT sensor for exhaust camshaft bank 2 connector.

    7. Disconnect the fuel pressure sensor connector.

    8. Disconnect the canister pump module connector.

    9. Disconnect the ECM connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F5-88 (VCPR) - Body ground Always 10 kΩ or higher
      A20-35 (VC) - Body ground Always 10 kΩ or higher
      F5-89 (VCE1) - Body ground Always 10 kΩ or higher
      F5-90 (VCE2) - Body ground Always 10 kΩ or higher
      F5-82 (VCV1) - Body ground Always 10 kΩ or higher
      F5-111 (VCV2) - Body ground Always 10 kΩ or higher
      F5-126 (VCTA) - Body ground Always 10 kΩ or higher
      F5-94 (VCPM) - Body ground Always 10 kΩ or higher

    11. Reconnect the ECM connectors.

    12. Reconnect the canister pump module connector.

    13. Reconnect the fuel pressure sensor connector.

    14. Reconnect the VVT sensor for exhaust camshaft bank 2 connector.

    15. Reconnect the VVT sensor for intake camshaft bank 2 connector.

    16. Reconnect the VVT sensor for exhaust camshaft bank 1 connector.

    17. Reconnect the VVT sensor for intake camshaft bank 1 connector.

    18. Reconnect the manifold absolute pressure sensor connector.

    19. Reconnect the throttle body with motor connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM Click here