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 source voltage to the sensors through the VC output circuit.

B00463CE67

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 engine switch is turned to on (IG). The MIL goes off when the engine is started.

WIRING DIAGRAM


B0047J6E01
B0046LUE01
*a Camshaft Position Sensor (for Intake Camshaft)
*b Camshaft Position Sensor (for Exhaust Camshaft)

CAUTION / NOTICE / HINT

Note

Check the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. CHECK MIL


    1. Check that the Malfunction Indicator Lamp (MIL) lights up when the engine switch is turned to on (IG).

      OK
      MIL lights up.
      Result
      Proceed to
      OK
      NG

    OK

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

    NG

  2. CHECK COMMUNICATION 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 for communication between the GTS and ECM.

      Result
      Result Proceed to
      Communication is not possible A
      Communication is possible B

    B

    CHECK ECU POWER SOURCE CIRCUIT

    A

  3. CHECK MIL (THROTTLE POSITION SENSOR)


    1. Disconnect the B29 throttle body with motor assembly connector.

    2. Turn the engine switch on (IG).

    3. Check the MIL.

      Tech Tips

      Perform "Inspection After Repair" after replacing the throttle body with motor assembly.

      Click here

      Result
      Result Proceed to
      MIL does not illuminate A
      MIL illuminates B

    B

    REPLACE THROTTLE BODY WITH MOTOR ASSEMBLY Click here

    A

  4. CHECK MIL (ACCELERATOR PEDAL POSITION SENSOR)


    1. Disconnect the A36 accelerator pedal sensor assembly connector.

    2. Turn the engine switch on (IG).

    3. Check the MIL.

      Result
      Result Proceed to
      MIL does not illuminate A
      MIL illuminates B

    B

    REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY Click here

    A

  5. CHECK MIL (VACUUM SENSOR (MANIFOLD ABSOLUTE PRESSURE SENSOR))


    1. Disconnect the B134 vacuum sensor (manifold absolute pressure sensor) connector.

    2. Turn the engine switch on (IG).

    3. Check the MIL.

      Tech Tips

      Perform "Inspection After Repair" after replacing the vacuum sensor (manifold absolute pressuresensor).

      Click here

      Result
      Result Proceed to
      MIL does not illuminate A
      MIL illuminates B

    B

    REPLACE VACUUM SENSOR (MANIFOLD ABSOLUTE PRESSURE SENSOR) Click here

    A

  6. CHECK MIL (CAMSHAFT POSITION SENSOR (FOR INTAKE CAMSHAFT))


    1. Disconnect the B32 camshaft position sensor (for intake camshaft) connector.

    2. Turn the engine switch on (IG).

    3. Check the MIL.

      Result
      Result Proceed to
      MIL does not illuminate A
      MIL illuminates B

    B

    REPLACE CAMSHAFR POSITION SENSOR (FOR INTAKE CAMSHAFT) Click here

    A

  7. CHECK MIL (CAMSHAFT POSITION SENSOR (FOR EXHAUST CAMSHAFT))


    1. Disconnect the B31 camshaft position sensor (for exhaust camshaft) connector.

    2. Turn the engine switch on (IG).

    3. Check the MIL.

      Result
      Result Proceed to
      MIL does not illuminate A
      MIL illuminates B

    B

    REPLACE CAMSHAFT POSITION SENSOR (FOR EXHAUST CAMSHAFT) Click here

    A

  8. CHECK HARNESS AND CONNECTOR


    1. Disconnect the B29 throttle body with motor assembly connector.

    2. Disconnect the A36 accelerator pedal sensor assembly connector.

    3. Disconnect the B134 vacuum sensor (manifold absolute pressure sensor) connector.

    4. Disconnect the B32 camshaft position sensor (for intake camshaft) connector.

    5. Disconnect the B31 camshaft position sensor (for exhaust camshaft) connector.

    6. Disconnect the A116, B142 and B143 ECM connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B142-5 (VCTA) - Body ground and other terminals Always 10 kΩ or higher
      A116-18 (VCPA) - Body ground and other terminals Always 10 kΩ or higher
      A116-45 (VCP2) - Body ground and other terminals Always 10 kΩ or higher
      B142-45 (VCPM) - Body ground and other terminals Always 10 kΩ or higher
      B143-5 (VCV1) - 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