SFI SYSTEM(w/o Canister Pump Module) VC Output Circuit

DESCRIPTION

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

B004PEJE40

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.

Tech Tips

Under normal conditions, the MIL is illuminated when the power switch is turned on (IG). The MIL goes off when the power switch is turned on (READY).

WIRING DIAGRAM


CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. CHECK GTS


    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.

      Tech Tips

      Communication can be checked by using the Data List item Engine.

      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. 2 FUSE VOLTAGE

    B004QKNC02
    *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
    *2 EFI NO. 2 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. 2 fuse) - Body ground Power switch on (IG) 11 to 14 V

      Tech Tips


      • Check the fuse with it installed to the No. 1 engine room relay block and No. 1 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 assembly connector.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Check the communication between the GTS and ECM.

      Tech Tips

      Communication can be checked by using the Data List item Engine.

      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 (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.

      Tech Tips

      Communication can be checked by using the Data List item Engine.

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

    B

    REPLACE CAMSHAFT POSITION SENSOR Click here

    A

  5. 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

      Communication can be checked by using the Data List item Engine.

      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 assembly connector.

    2. Disconnect the crankshaft 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
      C31-134 (VCTA) - Body ground Always 10 kΩ or higher
      C31-116 (VCV1) - Body ground Always 10 kΩ or higher
      C31-77 (VCPM) - Body ground Always 10 kΩ or higher
      A40-2 (+B) - 1 (EFI NO. 2 fuse) Always Below 1 Ω
      A40-3 (+B2) - 1 (EFI NO. 2 fuse) Always Below 1 Ω
      A40-2 (+B) - Body ground Always 10 kΩ or higher
      A40-3 (+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