SFI SYSTEM(w/ EGR System) VC Output Circuit

DESCRIPTION

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

A00217YE04

When the VC circuit is short-circuited, the microprocessor in the ECM and the sensors that are supplied with power through the VC circuit are inactivated because 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 power switch is turned on (IG). The MIL goes off when the power switch 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 CONNECTION 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 for 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. 2 FUSE VOLTAGE

    A002244C03
    *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 assembly, 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 power switch on (IG).

    3. Turn the GTS on.

    4. Check for 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 (CAMSHAFT POSITION SENSOR (FOR INTAKE CAMSHAFT))


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

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Check for 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

  5. 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 power switch on (IG).

    3. Turn the GTS on.

    4. Check for 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

  6. 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 for 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 MANIFOLD ABSOLUTE PRESSURE SENSOR Click here

    A

  7. 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 for 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 FUEL DELIVERY PIPE SUB-ASSEMBLY (FUEL PRESSURE SENSOR) Click here

    A

  8. CHECK HARNESS AND CONNECTOR


    1. Disconnect the throttle body with motor assembly connector.

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

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

    4. Disconnect the manifold absolute pressure sensor connector.

    5. Disconnect the fuel pressure sensor connector.

    6. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F5-102 (VCPR) - Body ground Always 10 kΩ or higher
      F5-111 (VCE1) - Body ground Always 10 kΩ or higher
      F5-113 (VCV1) - Body ground Always 10 kΩ or higher
      F5-125 (VCTA) - Body ground Always 10 kΩ or higher
      F5-78 (VCPM) - Body ground Always 10 kΩ or higher
      1 (EFI NO. 2 fuse) - A78-2 (+B) Always Below 1Ω
      1 (EFI NO. 2 fuse) - A78-3 (+B2) Always Below 1Ω
      A78-2 (+B) - Body ground Always 10 kΩ or higher
      A78-3 (+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