SFI SYSTEM VC Output Circuit

DESCRIPTION

The ECM constantly generates 5 V power from the 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.

A000PZIE51

When the VC circuit is short-circuited, the microprocessor in the ECM and sensors that are supplied with 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.

WIRING DIAGRAM


A000N2HE02
A000NY3E01
*a Throttle Position Sensor
*b Manifold Absolute Pressure Sensor

CAUTION / NOTICE / HINT

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. READ VALUE USING GTS


    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.

      Tech Tips

      It can be checked using the "Engine and ECT" item of the Data List.

      Result
      Result Proceed to
      Communication is not possible A
      Communication is possible B

    B

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

    A

  2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF ECM)


    1. A000RBRE01
      Text Illustration
      *1 No. 2 Engine Room Relay Block and Junction Block Assembly
      *2 EFI NO. 2 Fuse

      Turn the power switch on (IG).

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      1 (EFI NO. 2 fuse) - Body ground Power switch on (IG) 11 to 14 V

      Tech Tips


      • Check the fuse with it installed to the No. 2 engine room relay block and junction block assembly.

      • If the result is not as specified, since current is not flowing to the +B and +B2 terminals of the ECM, the system may not be started.


    NG

    GO TO ECM POWER SOURCE CIRCUIT Click here

    OK

  3. CHECK CONNECTION BETWEEN GTS AND ECM (THROTTLE POSITION SENSOR)


    1. Disconnect the throttle body connector.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      It can be checked using the "Engine and ECT" item of the Data List.

      Result
      Result Proceed to
      Communication is not possible A
      Communication is possible B

      Tech Tips

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


    B

    REPLACE THROTTLE BODY ASSEMBLY Click here

    A

  4. CHECK CONNECTION BETWEEN GTS AND ECM (VVT SENSOR for Intake Side of Bank 1)


    1. Disconnect the VVT sensor (for Intake Side of Bank 1) connector.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      It can be checked using the "Engine and ECT" item of the Data List.

      Result
      Result Proceed to
      Communication is not possible A
      Communication is possible B

    B

    REPLACE VVT SENSOR (for Intake Side of Bank 1) Click here

    A

  5. CHECK CONNECTION BETWEEN GTS AND ECM (VVT SENSOR for Intake Side of Bank 2)


    1. Disconnect the VVT sensor (for Intake Side of Bank 2) connector.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      It can be checked using the "Engine and ECT" item of the Data List.

      Result
      Result Proceed to
      Communication is not possible A
      Communication is possible B

    B

    REPLACE VVT SENSOR (for Intake Side of Bank 2) Click here

    A

  6. CHECK CONNECTION BETWEEN GTS AND ECM (VVT SENSOR for Exhaust Side of Bank 1)


    1. Disconnect the VVT sensor (for Exhaust Side of Bank 1) connector.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      It can be checked using the "Engine and ECT" item of the Data List.

      Result
      Result Proceed to
      Communication is not possible A
      Communication is possible B

    B

    REPLACE VVT SENSOR (for Exhaust Side of Bank 1) Click here

    A

  7. CHECK CONNECTION BETWEEN GTS AND ECM (VVT SENSOR for Exhaust Side of Bank 2)


    1. Disconnect the VVT sensor (for Exhaust Side of Bank 2) connector.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      It can be checked using the "Engine and ECT" item of the Data List.

      Result
      Result Proceed to
      Communication is not possible A
      Communication is possible B

    B

    REPLACE VVT SENSOR (for Exhaust Side of Bank 2) Click here

    A

  8. CHECK CONNECTION BETWEEN GTS AND ECM (FUEL PRESSURE SENSOR)


    1. Disconnect the fuel pressure sensor connector.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      It can be checked using the "Engine and ECT" item of the Data List.

      Result
      Result Proceed to
      Communication is not possible A
      Communication is possible B

      Tech Tips

      Perform "Inspection After Repair" after replacing the fuel pressure sensor Click here.


    B

    REPLACE FUEL PRESSURE SENSOR Click here

    A

  9. CHECK CONNECTION BETWEEN GTS AND ECM (MANIFOLD ABSOLUTE PRESSURE SENSOR)


    1. Disconnect the manifold absolute pressure sensor connector.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      It can be checked using the "Engine and ECT" item of the Data List.

      Result
      Result Proceed to
      Communication is not possible A
      Communication is possible B

      Tech Tips

      Perform "Inspection After Repair" after replacing the manifold absolute pressure sensor Click here.


    B

    REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR Click here

    A

  10. CHECK CONNECTION BETWEEN GTS AND ECM (CANISTER PUMP MODULE)


    1. Disconnect the canister pump module connector.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      It can be checked using the "Engine and ECT" item of the Data List.

      Result
      Result Proceed to
      Communication is not possible A
      Communication is possible B

    B

    REPLACE CANISTER PUMP MODULE Click here

    A

  11. CHECK HARNESS AND CONNECTOR


    1. Disconnect the throttle body connector.

    2. Disconnect the VVT sensor (for Intake Side of Bank 1) connector.

    3. Disconnect the VVT sensor (for Intake Side of Bank 2) connector.

    4. Disconnect the VVT sensor (for Exhaust Side of Bank 1) connector.

    5. Disconnect the VVT sensor (for Exhaust Side of Bank 2) connector.

    6. Disconnect the fuel pressure sensor connector.

    7. Disconnect the manifold absolute 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
      F5-82 (VCV1) - Body ground and other terminals Always 10 kΩ or higher
      F5-88 (VCPR) - Body ground and other terminals Always 10 kΩ or higher
      F5-89 (VCE1) - Body ground and other terminals Always 10 kΩ or higher
      F5-90 (VCE2) - Body ground and other terminals Always 10 kΩ or higher
      F5-94 (VCPM) - Body ground and other terminals Always 10 kΩ or higher
      F5-111 (VCV2) - Body ground and other terminals Always 10 kΩ or higher
      F5-126 (VCTA) - Body ground and other terminals Always 10 kΩ or higher
      A20-35 (VC) - Body ground and other terminals Always 10 kΩ or higher
      A20-2 (+B) - 1 (EFI NO. 2 fuse) Always Below 1 Ω
      A20-3 (+B2) - 1 (EFI NO. 2 fuse) Always Below 1 Ω
      A20-2 (+B) - Body ground and other terminals Always 10 kΩ or higher
      A20-3 (+B2) - Body ground and other terminals Always 10 kΩ or higher

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR