ECD SYSTEM > VC Output Circuit

for Preparation Click here


DESCRIPTION

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

A116143E90

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 to ON. The MIL turns off when the engine is started.


WIRING DIAGRAM


A199014E01


A199015E01


INSPECTION PROCEDURE

1.CHECK MIL

  1. Check that the Malfunction Indicator Lamp (MIL) lights up when turning the ignition switch to ON.
    Result 
    Result
    		Proceed to
    MIL does not illuminate
    		A
    MIL illuminates
    		B



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


2.CHECK COMMUNICATION BETWEEN INTELLIGENT TESTER AND ECM

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and tester on.

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



B
GO TO MIL CIRCUIT (Click here)
A


3.CHECK MIL (THROTTLE POSITION SENSOR)

  1. Disconnect the diesel throttle body assembly connector.

  1. Turn the ignition switch to ON.

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

  1. Reconnect the diesel throttle body assembly connector.



B
REPLACE DIESEL THROTTLE BODY ASSEMBLY (Click here)
A


4.CHECK MIL (ELECTRIC EGR VALVE ASSEMBLY)

  1. Disconnect the electric EGR valve assembly connector.

  1. Turn the ignition switch to ON.

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

  1. Reconnect the electric EGR valve assembly connector.



B
REPLACE ELECTRIC EGR CONTROL VALVE ASSEMBLY (Click here)
A


5.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 does not illuminate
    		A
    MIL illuminates
    		B

  1. Reconnect the accelerator pedal position sensor connector.



B
REPLACE ACCELERATOR PEDAL POSITION SENSOR ASSEMBLY (Click here)
A


6.CHECK MIL (TURBO PRESSURE SENSOR)

  1. Disconnect the turbo pressure sensor connector.

  1. Turn the ignition switch to ON.

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

  1. Reconnect the turbo pressure sensor connector.



B
REPLACE TURBO PRESSURE SENSOR (Click here)
A


7.CHECK MIL (NOZZLE VANE POSITION SENSOR)

  1. Disconnect the nozzle vane position sensor connector.

  1. Turn the ignition switch to ON.

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

  1. Reconnect the nozzle vane position sensor connector.



B
REPLACE TURBOCHARGER SUB-ASSEMBLY (Click here)
A


8.CHECK MIL (DIFFERENTIAL PRESSURE SENSOR)

  1. Disconnect the differential pressure sensor connector.

  1. Turn the ignition switch to ON.

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

  1. Reconnect the differential pressure sensor connector.



B
REPLACE DIFFERENTIAL PRESSURE SENSOR (Click here)
A


9.CHECK MIL (FUEL PRESSURE SENSOR)

  1. Disconnect the fuel pressure sensor connector.

  1. Turn the ignition switch to ON.

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

  1. Reconnect the fuel pressure sensor connector.



B
REPLACE COMMON RAIL ASSEMBLY (FUEL PRESSURE SENSOR) (Click here)
A


10.CHECK HARNESS AND CONNECTOR (VC CIRCUIT)


    A200322E01

  1. Disconnect the diesel throttle body assembly connector.

  1. Disconnect the electric EGR valve assembly connector.

  1. Disconnect the accelerator pedal position sensor connector.

  1. Disconnect the turbo pressure sensor connector.

  1. Disconnect the nozzle vane position sensor.

  1. Disconnect the differential pressure sensor connector.

  1. Disconnect the fuel pressure sensor connector and 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
    A19-46 (VVLU) - Body ground
    		Always
    		10 kΩ or higher
    B9-26 (VCEG) - Body ground
    		Always
    		10 kΩ or higher
    A19-56 (VCPA) - Body ground
    		Always
    		10 kΩ or higher
    A19-53 (VCP2) - Body ground
    		Always
    		10 kΩ or higher
    A19-14 (VPIM) - Body ground
    		Always
    		10 kΩ or higher
    B9-37 (VNVC) - Body ground
    		Always
    		10 kΩ or higher
    A19-33 (VCPX) - Body ground
    		Always
    		10 kΩ or higher
    B9-15 (VCS) - 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 diesel throttle body assembly, electric EGR valve assembly, accelerator pedal position sensor, turbo pressure sensor, nozzle vane position sensor, differential pressure sensor, and fuel pressure sensor connectors.

  1. Reconnect the ECM connectors.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (Click here)