СИСТЕМА SFI 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.

A005T8OE93

When the VC circuit is short-circuited, the microprocessor in the ECM and sensors that are supplied with power through the VC circuit are inactivated because the 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 for several seconds when the engine switch is first turned on (IG), and then goes off when the engine starts.

WIRING DIAGRAM

A005V7TE04

INSPECTION PROCEDURE

PROCEDURE

  1. CHECK MIL CONDITION

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

      OK
      MIL lights up.
    NG

    CHECK CONNECTION BETWEEN INTELLIGENT TESTER AND ECM Click here

    OK

    SYSTEM OK

  2. CHECK CONNECTION BETWEEN INTELLIGENT TESTER AND ECM

    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG) and turn the tester on.

    3. Check the communication between the tester and ECM.

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

    GO TO MIL CIRCUIT Click here

    A

  3. CHECK MIL (VARIABLE RESISTOR)

    1. Disconnect the A49 variable resistor connector.

    2. Turn the engine switch on (IG).

    3. Check the MIL.

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

    4. Reconnect the variable resistor connector.

    B

    REPLACE VARIABLE RESISTOR

    A

  4. CHECK MIL (THROTTLE POSITION SENSOR)

    1. Disconnect the B7 throttle body connector.

    2. Turn the engine switch on (IG).

    3. Check the MIL.

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

    4. Reconnect the throttle body connector.

    B

    REPLACE THROTTLE BODY ASSEMBLY Click here

    A

  5. CHECK MIL (ACCELERATOR PEDAL POSITION SENSOR)

    1. Disconnect the A2 accelerator pedal position sensor connector.

    2. Turn the engine switch on (IG).

    3. Check the MIL.

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

    4. Reconnect the accelerator pedal position sensor connector.

    B

    REPLACE ACCELERATOR PEDAL ASSEMBLY Click here

    A

  6. CHECK HARNESS AND CONNECTOR (VARIABLE RESISTOR - THROTTLE BODY - ACCELERATOR PEDAL POSITION SENSOR)

    1. Disconnect the A49 variable resistor connector.

      A005V1FE04

    2. Disconnect the B7 throttle body connector.

    3. Disconnect the A2 accelerator pedal position sensor connector.

    4. Disconnect the A40 and B39 ECM connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B39-117 (VC) - Body ground Always 10 kΩ or higher
      B39-67 (VCTA) - Body ground
      A40-57 (VCPA) - Body ground
      A40-58 (VCP2) - Body ground
      Text in Illustration
      *1

      Front view of wire harness connector

      (to ECM)

    6. Reconnect the variable resistor connector.

    7. Reconnect the throttle body connector.

    8. Reconnect the accelerator pedal position sensor connector.

    9. Reconnect the ECM connectors.

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM Click here