SFI SYSTEM(w/o EGR System) VC Output Circuit

DTC Code DTC Name
VC Output Circuit

DESCRIPTION

The ECM constantly generates 5 V power source voltage from the auxiliary battery voltages 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.

A256646E36

When the VC circuit has a short circuit, the microprocessor in the ECM and sensors that are supplied power through the VC circuit are deactivated because power is not supplied from the VC circuit. When the system is in this condition, it will not start.

WIRING DIAGRAM

  • For the circuit diagram of the ECM power source, refer to the ECM power source circuit.

    Click here

  • VC Output Circuit

    A261346E05

PROCEDURE

  1. CHECK COMMUNICATION 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.

      Tip:

      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 EFI NO. 1 FUSE VOLTAGE

    A376214C01

    *1

    Engine Room Relay Block and Junction Block Assembly

    *2

    EFI NO. 1 Fuse

    1. 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. 1 fuse) - Body ground

      Power switch on (IG)

      11 to 14 V
      Tip:

      • Check the fuse with it installed to the 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.

    Result

    Proceed to

    OK

    NG
    NG

    GO TO ECM POWER SOURCE CIRCUIT

    Click here

    OK

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

    1. Disconnect the throttle body with motor assembly connector.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tip:

      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
    Tip:

    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 COMMUNICATION BETWEEN GTS AND ECM (CAMSHAFT POSITION SENSOR)

    1. Disconnect the camshaft position sensor connector.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tip:

      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 CAMSHAFT POSITION SENSOR

    Click here

    A

  5. CHECK COMMUNICATION 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.

      Tip:

      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 MANIFOLD ABSOLUTE PRESSURE SENSOR

    Click here

    A

  6. CHECK HARNESS AND CONNECTOR

    1. Disconnect the throttle body with motor assembly connector.

    2. Disconnect the camshaft position sensor connector.

    3. Disconnect the manifold absolute pressure sensor connector.

    4. Disconnect the ECM connectors.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      B3-5 (VC) or B75-125 (VCTA) - Body ground and other terminals

      Always

      10 kΩ or higher

      B39-3 (VC) or B75-113 (VCV1) - Body ground and other terminals

      Always

      10 kΩ or higher

      B45-3 (VC) or B75-78 (VCPM) - Body ground and other terminals

      Always

      10 kΩ or higher

      V3-6 (VCC) or A62-34 (VCPP) - Body ground and other terminals

      Always

      10 kΩ or higher

      1 (EFI NO. 1 fuse) - A62-2 (+B)

      Always

      Below 1 Ω

      1 (EFI NO. 1 fuse) - A62-3 (+B2)

      Always

      Below 1 Ω

      1 (EFI NO. 1 fuse) or A62-2 (+B) - Body ground and other terminals

      Always

      10 kΩ or higher

      1 (EFI NO. 1 fuse) or A62-3 (+B2) - Body ground and other terminals

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE ECM

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR