SFI SYSTEM (w/ Secondary Air Injection System) > VC Output Circuit

for Preparation Click here


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.

A240424E07

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.

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

WIRING DIAGRAM


A320869E01


INSPECTION PROCEDURE

1.CHECK MIL

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

    OK:
    MIL lights up.


NG
Go to step 2
OK

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

2.CHECK COMMUNICATION BETWEEN INTELLIGENT TESTER AND ECM

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the intelligent tester on.

  1. Check the communication between the intelligent tester and ECM.

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


A
GO TO MIL CIRCUIT (Click here)
B


3.CHECK MIL (THROTTLE POSITION SENSOR)

  1. Disconnect the throttle body with motor connector.

  1. Turn the ignition switch to ON.

  1. Check the MIL.

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


A
REPLACE THROTTLE BODY WITH MOTOR 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


A
REPLACE ACCELERATOR PEDAL ROD ASSEMBLY (Click here)
B


5.CHECK HARNESS AND CONNECTOR

  1. Disconnect the throttle body with motor connector.

  1. Disconnect the accelerator pedal position sensor connector.

  1. Disconnect the ECM connectors.

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

    Standard Resistance:

    Tester Connection
    		Condition
    		Specified Condition
    E11-18 (VC) - Body ground
    		Always
    		10 kΩ or higher
    E8-26 (VCPA) - Body ground
    		Always
    		10 kΩ or higher
    E8-27 (VCP2) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (Click here)