SFI SYSTEM VC Output Circuit

DESCRIPTION

The ECM constantly generates a 5 V power source voltage from the battery voltage supplied to the +B, +B2 (BATT) terminals to operate the microprocessor. The ECM also provides this power source voltage to the sensors through the VC output circuit.

B004KHJE53

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


CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. CHECK COMMUNICATION BETWEEN GTS AND ECM


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    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

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

    A

  2. CHECK EFI NO. 1 FUSE VOLTAGE

    B0071CBC03
    *1 Engine Room Relay Block and Junction Block Assembly
    *2 EFI NO. 1 Fuse

    1. Turn the ignition switch to ON.

    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 Ignition switch ON 11 to 14 V

      Tech Tips


      • 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 CONNECTION BETWEEN GTS AND ECM (THROTTLE POSITION SENSOR)


    1. Disconnect the throttle body with motor assembly connector.

    2. Turn the ignition switch to ON.

    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 with motor assembly.

      Click here


    B

    REPLACE THROTTLE BODY WITH MOTOR ASSEMBLY Click here

    A

  4. CHECK CONNECTION BETWEEN GTS AND ECM (ACCELERATOR PEDAL POSITION SENSOR)


    1. Disconnect the accelerator pedal sensor assembly connector.

    2. Turn the ignition switch to ON.

    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 (w/ Tumble Control Valve) A
      Communication is not possible (w/o Tumble Control Valve) B
      Communication is possible C

    B

    GO TO STEP 6 Click here

    C

    REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY Click here

    A

  5. CHECK CONNECTION BETWEEN GTS AND ECM (INTAKE AIR CONTROL VALVE ACTUATOR (FOR TUMBLE CONTROL VALVE))


    1. Disconnect the intake air control valve actuator (for tumble control valve) connector.

    2. Turn the ignition switch to ON.

    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 INTAKE AIR CONTROL VALVE ACTUATOR (FOR TUMBLE CONTROL VALVE) Click here

    A

  6. CHECK CONNECTION BETWEEN GTS AND ECM (CAMSHAFT POSITION SENSOR FOR INTAKE CAMSHAFT)


    1. Disconnect the camshaft position sensor (for intake camshaft) connector.

    2. Turn the ignition switch to ON.

    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 CAMSHAFT POSITION SENSOR (FOR INTAKE CAMSHAFT) Click here

    A

  7. CHECK CONNECTION BETWEEN GTS AND ECM (CAMSHAFT POSITION SENSOR FOR EXHAUST CAMSHAFT)


    1. Disconnect the camshaft position sensor (for exhaust camshaft) connector.

    2. Turn the ignition switch to ON.

    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 CAMSHAFT POSITION SENSOR (FOR EXHAUST CAMSHAFT) Click here

    A

  8. CHECK HARNESS AND CONNECTOR


    1. Disconnect the throttle body with motor assembly connector.

    2. Disconnect the accelerator pedal sensor assembly connector.

    3. Disconnect the intake air control valve actuator (for tumble control valve)* connector.

    4. Disconnect the camshaft position sensor (for intake camshaft) connector.

    5. Disconnect the camshaft position sensor (for exhaust camshaft) connector.

    6. Disconnect the ECM connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      C58-134 (VCTA) - Body ground and other terminals Always 10 kΩ or higher
      A22-49 (VCPA) - Body ground and other terminals Always 10 kΩ or higher
      A22-52 (VCP2) - Body ground and other terminals Always 10 kΩ or higher
      C58-96 (VCIA) - Body ground and other terminals Always 10 kΩ or higher
      C58-111 (VCE1) - Body ground and other terminals Always 10 kΩ or higher
      C58-116 (VCV1) - Body ground and other terminals Always 10 kΩ or higher

      *: w/ Tumble Control Valve

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

      Tech Tips

      Remove the EFI-MAIN NO. 2 relay connected between the checked terminals as the coil inside the relay influences the measurement value.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A22-2 (+B) - 1 (EFI NO. 1 fuse) Always Below 1 Ω
      A22-3 (+B2) - 1 (EFI NO. 1 fuse) Always Below 1 Ω
      A22-2 (+B) - Body ground Always 10 kΩ or higher
      A22-3 (+B2) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR