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) terminal to operate the microprocessor. The ECM also provides this power source voltage to the sensors through the VC output circuit.

B001E4OE72

When the VC circuit is short-circuited, the microprocessor in the ECM and sensors that are supplied with power through the VC circuit are deactivated 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 when the engine switch is turned on (IG). The MIL goes off when the engine is started.

WIRING DIAGRAM


CAUTION / NOTICE / HINT

Note

Check 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 engine 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" item of the Data List.

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

    B
    A
  2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF ECM)


    1. Turn the engine switch on (IG).

    2. B001DRNC04
      *A for Automatic Transmission
      *B for Manual Transmission
      *a

      Component with harness connected

      (ECM)

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G55-23 (+B) - C36-12 (E1) Engine switch on (IG) 11 to 14 V
      G55-22 (+B2) - C36-12 (E1) Engine switch on (IG) 11 to 14 V

      Tech Tips

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


    1. Disconnect the throttle body with motor assembly connector.

    2. Turn the engine 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" item of the Data List.

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

      Tech Tips

      for Automatic Transmission


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

        Click here


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


    1. Disconnect the accelerator pedal sensor assembly connector.

    2. Turn the engine 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" item of the Data List.

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

    B
    A
  5. 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 engine 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" item of the Data List.

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

    B
    A
  6. 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 engine 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" item of the Data List.

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

    B
    A
  7. 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 engine 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" item of the Data List.

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

    B
    A
  8. 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 engine 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" item of the Data List.

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

    B
    A
  9. CHECK CONNECTION BETWEEN GTS AND ECM (POWER STEERING OIL PRESSURE SWITCH)


    1. Disconnect the power steering oil pressure switch connector.

    2. Turn the engine 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" item of the Data List.

      Result
      Result Proceed to
      Communication is not possible (for Automatic Transmission) A
      Communication is not possible (for Manual Transmission) B
      Communication is possible C

    B
    C
    A
  10. CHECK CONNECTION BETWEEN GTS AND ECM (EMISSION CONTROL VALVE SET)


    1. Disconnect the emission control valve set connector.

    2. Turn the engine 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" item of the Data List.

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

    B
    A
  11. CHECK CONNECTION BETWEEN GTS AND ECM (NO. 2 EMISSION CONTROL VALVE SET)


    1. Disconnect the No. 2 emission control valve set connector.

    2. Turn the engine 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" item of the Data List.

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

    B
    A
  12. CHECK HARNESS AND CONNECTOR


    1. Disconnect the throttle body with motor assembly connector.

    2. Disconnect the accelerator pedal sensor assembly connector.

    3. Disconnect the VVT sensor (for intake side of bank 1) connector.

    4. Disconnect the VVT sensor (for intake side of bank 2) connector.

    5. Disconnect the VVT sensor (for exhaust side of bank 1) connector.

    6. Disconnect the VVT sensor (for exhaust side of bank 2) connector.

    7. Disconnect the emission control valve set connector.

    8. Disconnect the No. 2 emission control valve set connector.

    9. Disconnect the ECM connectors.

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

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      G56-6 (VCPA) - Body ground Always 10 kΩ or higher
      G56-3 (VCP2) - Body ground Always 10 kΩ or higher
      C36-2 (VCTA) - Body ground Always 10 kΩ or higher
      C35-13 (VCAP) - Body ground Always 10 kΩ or higher
      C34-12 (VCV1) - Body ground Always 10 kΩ or higher
      C34-6 (VCV2) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK
    NG
  13. CHECK HARNESS AND CONNECTOR


    1. Disconnect the throttle body with motor assembly connector.

    2. Disconnect the accelerator pedal sensor assembly connector.

    3. Disconnect the VVT sensor (for intake side of bank 1) connector.

    4. Disconnect the VVT sensor (for intake side of bank 2) connector.

    5. Disconnect the VVT sensor (for exhaust side of bank 1) connector.

    6. Disconnect the VVT sensor (for exhaust side of bank 2) connector.

    7. Disconnect the ECM connectors.

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

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      G56-4 (VCPA) -Body ground Always 10 kΩ or higher
      G56-2 (VCP2) -Body ground Always 10 kΩ or higher
      C36-13 (VCTA) -Body ground Always 10 kΩ or higher
      C34-15 (VCV1) -Body ground Always 10 kΩ or higher
      C34-16 (VCV2) -Body ground Always 10 kΩ or higher
      C88-18 (VCV2) - Body ground and other terminals Always 10 kΩ or higher
      C89-23 (VC) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK
    NG