SFI SYSTEM VC Output Circuit

DESCRIPTION

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

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

  

  

  *a	Accelerator Pedal Sensor Assembly
  *b	VCVG
  *c	Mass Air Flow Meter Sub-assembly
  *d	Fuel Pressure Sensor

CAUTION / NOTICE / HINT

PROCEDURE

1. CHECK CONNECTION BETWEEN GTS AND ECM

   
   

   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

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

   A

2. CHECK EFI NO. 1 FUSE VOLTAGE

   

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

   
   

   1. Turn the engine 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 Engine switch on (IG) 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 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

      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 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

   REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY Click here

   A

5. CHECK CONNECTION BETWEEN GTS AND ECM (CRANK POSITION SENSOR)

   
   

   1. Disconnect the crank position sensor 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

   REPLACE CRANK POSITION SENSOR 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 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

   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 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

   REPLACE CAMSHAFT POSITION SENSOR (FOR EXHAUST CAMSHAFT) Click here

   A

8. CHECK CONNECTION BETWEEN GTS AND ECM (MANIFOLD ABSOLUTE PRESSURE SENSOR)

   
   

   1. Disconnect the manifold absolute pressure sensor 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

   REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR Click here

   A

9. CHECK CONNECTION BETWEEN GTS AND ECM (OIL PRESSURE SENSOR (OIL PRESSURE SENDER GAUGE ASSEMBLY))

   
   

   1. Disconnect the oil pressure sensor (oil pressure sender gauge 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

   REPLACE OIL PRESSURE SENSOR (OIL PRESSURE SENDER GAUGE ASSEMBLY) Click here

   A

10. CHECK CONNECTION BETWEEN GTS AND ECM (FUEL PRESSURE SENSOR)

    
    

    1. Disconnect the fuel pressure sensor 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

       Perform "Inspection After Repair" after replacing the fuel pressure sensor.

       Click here

    
    

    B

    REPLACE FUEL PRESSURE SENSOR Click here

    A

11. CHECK CONNECTION BETWEEN GTS AND ECM (MASS AIR FLOW METER SUB-ASSEMBLY)

    
    

    1. Disconnect the mass air flow meter sub-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

       Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly.

       Click here

    
    

    B

    REPLACE MASS AIR FLOW METER SUB-ASSEMBLY Click here

    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 crank position sensor connector.

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

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

    6. Disconnect the oil pressure sensor (oil pressure sender gauge assembly) connector.

    7. Disconnect the fuel pressure sensor connector.

    8. Disconnect the manifold absolute pressure sensor connector.

    9. Disconnect the mass air flow meter sub-assembly connector.

    10. Disconnect the ECM connectors.

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

        Standard Resistance

        Tester Connection Condition Specified Condition C58-121 (VCTA) - Body ground Always 10 kΩ or higher A78-49 (VCPA) - Body ground Always 10 kΩ or higher A78-52 (VCP2) - Body ground Always 10 kΩ or higher C58-110 (VCNE) - Body ground Always 10 kΩ or higher C58-113 (VCV1) - Body ground Always 10 kΩ or higher C58-111 (VCE1) - Body ground Always 10 kΩ or higher C58-130 (VCPE) - Body ground Always 10 kΩ or higher C58-136 (VCPR) - Body ground Always 10 kΩ or higher C58-138 (VCPM) - Body ground Always 10 kΩ or higher C58-90 (VCVG) - Body ground Always 10 kΩ or higher

    12. Remove the EFI NO. 1 fuse, EFI-MAIN NO. 2 relay and EFI-MAIN NO. 3 relay from the engine room relay block and junction block assembly.

        Tech Tips

        Remove the EFI-MAIN NO. 2 and EFI-MAIN NO. 3 relays connected between the checked terminals as the coil inside the relay influences the measurement value.

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

        Standard Resistance
        Tester Connection Condition Specified Condition A78-2 (+B) - 1 (EFI NO. 1 fuse) Always Below 1 Ω A78-3 (+B2) - 1 (EFI NO. 1 fuse) Always Below 1 Ω 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