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 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

  

  

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. 2 FUSE VOLTAGE

   
   

   1. Turn the engine switch on (IG).

      

      *A	for LHD	*B	for RHD
      *1	No. 1 Engine Room Relay Block Assembly	*2	EFI NO. 2 Relay

   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 Engine 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 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 (CRANKSHAFT POSITION SENSOR)

   
   

   1. Disconnect the crankshaft 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 CRANKSHAFT POSITION SENSOR Click here

   A

6. CHECK CONNECTION BETWEEN GTS AND ECM (VVT SENSOR (FOR INTAKE CAMSHAFT OF BANK 1))

   
   

   1. Disconnect the VVT sensor (for intake camshaft 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

   REPLACE VVT SENSOR (FOR INTAKE CAMSHAFT OF BANK 1) Click here

   A

7. CHECK CONNECTION BETWEEN GTS AND ECM (VVT SENSOR (FOR INTAKE CAMSHAFT OF BANK 2))

   
   

   1. Disconnect the VVT sensor (for intake camshaft 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

   REPLACE VVT SENSOR (FOR INTAKE CAMSHAFT OF BANK 2) Click here

   A

8. CHECK CONNECTION BETWEEN GTS AND ECM (VVT SENSOR (FOR EXHAUST CAMSHAFT OF BANK 1))

   
   

   1. Disconnect the VVT sensor (for exhaust camshaft 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

   REPLACE VVT SENSOR (FOR EXHAUST CAMSHAFT OF BANK 1) Click here

   A

9. CHECK CONNECTION BETWEEN GTS AND ECM (VVT SENSOR (FOR EXHAUST CAMSHAFT OF BANK 2))

   
   

   1. Disconnect the VVT sensor (for exhaust camshaft 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

   REPLACE VVT SENSOR (FOR EXHAUST CAMSHAFT OF BANK 2) Click here

   A

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

    
    

    1. Disconnect the fuel pressure sensor (for high pressure side) 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 (for high pressure side).

       Click here

    
    

    B

    REPLACE FUEL DELIVERY PIPE WITH SENSOR ASSEMBLY LH (FUEL PRESSURE SENSOR (FOR HIGH PRESSURE SIDE)) Click here

    A

11. CHECK CONNECTION BETWEEN GTS AND ECM (FUEL PRESSURE SENSOR (FOR LOW PRESSURE SIDE))

    
    

    1. Disconnect the fuel pressure sensor (for low pressure side) 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 (for low pressure side).

       Click here

    
    

    B

    REPLACE FUEL DELIVERY PIPE SUB-ASSEMBLY (FUEL PRESSURE SENSOR (FOR LOW PRESSURE SIDE)) Click here

    A

12. 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

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 crankshaft position sensor connector.

    4. Disconnect the VVT sensor (for intake camshaft of bank 1) connector.

    5. Disconnect the VVT sensor (for intake camshaft of bank 2) connector.

    6. Disconnect the VVT sensor (for exhaust camshaft of bank 1) connector.

    7. Disconnect the VVT sensor (for exhaust camshaft of bank 2) connector.

    8. Disconnect the fuel pressure sensor (for high pressure side) connector.

    9. Disconnect the fuel pressure sensor (for low pressure side) connector.

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

    11. Disconnect the ECM connectors.

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

        Standard Resistance

        Tester Connection Condition Specified Condition D65-121 (VCTA) - Body ground Always 10 kΩ or higher A56-49 (VCPA) - Body ground Always 10 kΩ or higher A56-52 (VCP2) - Body ground Always 10 kΩ or higher D65-96 (VCNE) - Body ground Always 10 kΩ or higher D65-90 (VC) - Body ground Always 10 kΩ or higher A56-2 (+B) - 1 (EFI NO. 2 fuse) Always Below 1 Ω A56-3 (+B2) - 1 (EFI NO. 2 fuse) Always Below 1 Ω A56-2 (+B) - Body ground Always 10 kΩ or higher A56-3 (+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