SFI SYSTEM VC Output Circuit

DESCRIPTION

The ECM constantly generates a 5 V power source voltage from the battery voltage supplied to the +B (BATT) terminal to operate the microprocessor. The ECM also provides this power source voltage 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

  

  *a	Camshaft Position Sensor (for Intake Side)
  *b	Camshaft Position Sensor (for Exhaust Side)
  *c	VCVG
  *d	Mass Air Flow Meter Sub-assembly

  

  *a	Throttle Body with Motor Assembly
  *b	Accelerator Pedal Sensor Assembly

CAUTION / NOTICE / HINT

PROCEDURE

1. READ VALUE USING GTS

   
   

   1. Connect the GTS to the DLC3.

   2. Turn the ignition switch to ON.

   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)

   

   *a	Component with harness connected (ECM)

   
   

   1. Turn the ignition switch to ON.

   2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition G46-1(+B) - Body ground Ignition switch ON 11 to 14 V G46-2(+B2) - Body ground Ignition switch ON 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 throttle body with motor assembly connector.

   2. Turn the ignition switch to ON.

   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 WITH MOTOR BODY 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 ignition switch to ON.

   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 SUB-ASSEMBLY)

   
   

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

   2. Turn the ignition switch to ON.

   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

6. CHECK CONNECTION BETWEEN GTS AND ECM (CAMSHAFT POSITION SENSOR FOR INTAKE SIDE)

   
   

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

   2. Turn the ignition switch to ON.

   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 SIDE) Click here

   A

7. CHECK CONNECTION BETWEEN GTS AND ECM (CAMSHAFT POSITION SENSOR FOR EXHAUST SIDE)

   
   

   1. Disconnect the camshaft position sensor (for exhaust side) connector.

   2. Turn the ignition switch to ON.

   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 SIDE) Click here

   A

8. CHECK HARNESS AND CONNECTOR

   
   

   1. Disconnect the throttle body with motor assembly connector.

   2. Disconnect the accelerator pedal sensor assembly connector.

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

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

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

   6. Disconnect the ECM connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition C52-29 (VCTA) - Body ground Always 10 kΩ or higher G46-20 (VCPA) - Body ground Always 10 kΩ or higher G46-22 (VCP2) - Body ground Always 10 kΩ or higher C53-33 (VCVG) - Body ground Always 10 kΩ or higher C52-31 (VCE1) - Body ground Always 10 kΩ or higher C52-21 (VCV1) - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE ECM Click here

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR