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

DESCRIPTION

The ECM constantly generates 5 V power source voltage from the battery voltages supplied to the +B, +B2 (BATT) terminal 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 Power Source Circuit

CAUTION / NOTICE / HINT

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

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

   A

2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF ECM)

   
   

   1. Turn the engine switch on (IG).

   2. 

      *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 A12-7 (+B) - E3-1 (E1) Engine switch on (IG) 11 to 14 V A12-6 (+B2) - E3-1 (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

   GO TO ECM POWER SOURCE CIRCUIT Click here

   OK

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

   
   

   1. Disconnect the E36 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 SENSOR)

   
   

   1. Disconnect the A1 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 (MASS AIR FLOW METER)

   
   

   1. Disconnect the E38 mass air flow meter 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.

      Click here

   
   

   B

   REPLACE MASS AIR FLOW METER Click here

   A

6. CHECK CONNECTION BETWEEN GTS AND ECM (FUEL DELIVERY PIPE LH (FUEL PRESSURE SENSOR))

   
   

   1. Disconnect the H17 fuel delivery pipe LH (fuel pressure sensor).

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

   A

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

   
   

   1. Disconnect the E21 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

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

   
   

   1. Disconnect the E27 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

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

   
   

   1. Disconnect the E16 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

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

    
    

    1. Disconnect the E29 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

11. CHECK CONNECTION BETWEEN GTS AND ECM (CAMSHAFT POSITION SENSOR)

    
    

    1. Disconnect the E37 camshaft 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 CAMSHAFT POSITION SENSOR Click here

    A

12. CHECK CONNECTION BETWEEN GTS AND ECM (CRANKSHAFT POSITION SENSOR)

    
    

    1. Disconnect the c1 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

13. CHECK CONNECTION BETWEEN GTS AND ECM (CANISTER PUMP MODULE)

    
    

    1. Disconnect the U34 canister pump module 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 CHARCOAL CANISTER ASSEMBLY Click here

    A

14. CHECK HARNESS AND CONNECTOR

    
    

    1. Disconnect the E36 throttle body with motor assembly connector.

    2. Disconnect the A1 accelerator pedal sensor assembly connector.

    3. Disconnect the E38 mass air flow meter connector.

    4. Disconnect the H17 fuel delivery pipe LH (fuel pressure sensor) connector.

    5. Disconnect the E21 VVT sensor (for intake camshaft of bank 1) connector.

    6. Disconnect the E27 VVT sensor (for intake camshaft of bank 2) connector.

    7. Disconnect the E16 VVT sensor (for exhaust camshaft of bank 1) connector.

    8. Disconnect the E29 VVT sensor (for exhaust camshaft of bank 2) connector.

    9. Disconnect the E37 camshaft position sensor connector.

    10. Disconnect the c1 crankshaft position sensor connector.

    11. Disconnect the U34 canister pump module connector.

    12. Disconnect the E2, A12, E1 and E4 ECM connectors.

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

        Standard Resistance

        Tester Connection Condition Specified Condition E2-26 (VC) - Body ground and other terminals Always 10 kΩ or higher E2-34 (VCTA) - Body ground and other terminals Always 10 kΩ or higher A12-20 (VCPA) - Body ground and other terminals Always 10 kΩ or higher A12-22 (VCP2) - Body ground and other terminals Always 10 kΩ or higher E1-21 (VCVG) - Body ground and other terminals Always 10 kΩ or higher E4-28 (VCPR) - Body ground and other terminals Always 10 kΩ or higher

        Result
        Proceed to OK NG

    
    

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR