SFI SYSTEM > VC Output Circuit

for Preparation Click here


DESCRIPTION

The ECM constantly generates 5 V power from the battery voltages supplied to the +B (BATT) terminal to operate the microprocessor. The ECM also provides this power to the sensors through the VC output circuit.

A116143E33

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.

HINT:
Under normal conditions, the MIL is illuminated for several seconds when the ignition switch is first turned ON. The MIL goes off when the engine is started.


WIRING DIAGRAM


A201219E06


INSPECTION PROCEDURE

1.CHECK MIL CONDITION

  1. Check that the Malfunction Indicator Lamp (MIL) lights up when turning the ignition switch to ON.

    OK:
    MIL lights up.



NG
Go to step 2
OK

END 

2.CHECK CONNECTION BETWEEN INTELLIGENT TESTER AND ECM

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

  1. Check for communication between the tester and ECM.
    Result 
    Result
    		Proceed to
    Communication possible
    		A
    Communication not possible
    		B



A
GO TO MIL CIRCUIT (Click here)
B


3.CHECK MIL (THROTTLE POSITION SENSOR)

  1. Disconnect the throttle body assembly connector.

  1. Turn the ignition switch to ON.

  1. Check the MIL.
    Result 
    Result
    		Proceed to
    MIL illuminates
    		A
    MIL does not illuminate
    		B

  1. Reconnect the throttle body assembly connector.



A
REPLACE THROTTLE BODY ASSEMBLY (Click here)
B


4.CHECK MIL (ACCELERATOR PEDAL POSITION SENSOR)

  1. Disconnect the accelerator pedal position sensor connector.

  1. Turn the ignition switch to ON.

  1. Check the MIL.
    Result 
    Result
    		Proceed to
    MIL illuminates
    		A
    MIL does not illuminate
    		B

  1. Reconnect the accelerator pedal position sensor connector.



A
REPLACE ACCELERATOR PEDAL ASSEMBLY (Click here)
B


5.CHECK MIL (MANIFOLD ABSOLUTE PRESSURE SENSOR)

  1. Disconnect the manifold absolute pressure sensor connector.

  1. Turn the ignition switch to ON.

  1. Check the MIL.
    Result 
    Result
    		Proceed to
    MIL illuminates
    		A
    MIL does not illuminate
    		B

  1. Reconnect the manifold absolute pressure sensor connector.



A
REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR
B


6.CHECK HARNESS AND CONNECTOR (VC CIRCUIT)

  1. Disconnect the throttle body assembly connector.

  1. Disconnect the accelerator pedal position sensor assembly connector.

  1. Disconnect the manifold absolute pressure sensor connector.



    A201350E02

  1. Disconnect the ECM connectors.

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

    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    B8-89 (VCTA) - Body ground
    		Always
    		10 kΩ or higher
    A18-57 (VCPA) - Body ground
    		Always
    		10 kΩ or higher
    A18-58 (VCP2) - Body ground
    		Always
    		10 kΩ or higher
    B8-67 (VC) - Body ground
    		Always
    		10 kΩ or higher

    Text in Illustration 
    *1
    		Front view of wire harness connector:
    (to ECM)
    *2
    		Front view of wire harness connector:
    (to ECM)

  1. Reconnect the throttle body assembly connector.

  1. Reconnect the accelerator pedal position sensor connector.

  1. Reconnect the manifold absolute pressure sensor connector.

  1. Reconnect the ECM connectors.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (Click here)