SFI SYSTEM > MIL Circuit

for Preparation Click here


DESCRIPTION

The MIL (Malfunction Indicator Lamp) is used to indicate vehicle malfunction detections by the ECM. When the ignition switch is turned to ON, power is supplied to the MIL circuit, and the ECM provides the circuit ground which illuminates the MIL.
The MIL operation can be checked visually: When the ignition switch is turned to ON, the MIL should illuminate and should turn off after engine is started. If the MIL remains illuminated or does not illuminate, conduct the following troubleshooting procedure using the Techstream.

WIRING DIAGRAM


A187063E04


INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
1.CHECK THAT MIL ILLUMINATES

  1. Perform troubleshooting in accordance with the table below.

    Result:

    MIL Condition
    		Proceed to
    MIL remains ON
    		A
    MIL does not illuminate
    		B


B
Go to step 5
A


2.CHECK WHETHER DTC OUTPUT RECURS

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

  1. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

  1. Check if any DTCs have been detected. Write down any DTCs.

    Result:

    Result
    		Proceed to
    No DTC detected
    		A
    DTCs are detected
    		B

    HINT:
    Check for detected DTCs output from other ECUs which relate to the MIL.


B
REPAIR CIRCUITS INDICATED BY OUTPUT DTCS (Click here)
A


3.CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS)

  1. Disconnect the A50 ECM connector.

  1. Turn the ignition switch to ON.

  1. Check that the MIL does not illuminate.

    OK:
    MIL not illuminated.

  1. Reconnect the ECM connector.



NG
Go to step 4
OK

REPLACE ECM (Click here)  

4.CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM)

  1. Disconnect the ECM connector.

  1. Disconnect the combination meter connector.

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

    Standard Resistance (Check for Short):

    Tester Connection
    		Condition
    		Specified Condition
    A50-24 (W) or E46-20 (EFI) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the ECM connector.

  1. Reconnect the combination meter connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (COMBINATION METER - ECM)
OK

REPLACE COMBINATION METER (Click here)  

5.CHECK THAT MIL IS ILLUMINATED

  1. Check if the MIL is illuminated when the ignition switch is turned to ON.

    OK:
    MIL should be illuminated.


NG
Go to step 6
OK

CHECK FOR INTERMITTENT PROBLEMS (Click here)  

6.CHECK THAT ENGINE STARTS

  1. Turn the ignition switch to ON.

  1. Start the engine.

    Result:

    Result
    		Proceed to
    Engine starts
    		A
    Engine does not start*
    		B

    HINT:
    *: The Techstream cannot communicate with the ECM.


B
GO TO VC OUTPUT CIRCUIT (Click here)
A


7.CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM)

  1. Disconnect the ECM connector.

  1. Disconnect the combination meter connector.

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

    Standard Resistance (Check for Open):

    Tester Connection
    		Condition
    		Specified Condition
    A50-24 (W) - E46-20 (EFI)
    		Always
    		Below 1 Ω

  1. Reconnect the ECM connector.

  1. Reconnect the combination meter connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (COMBINATION METER - ECM)
OK

REPLACE COMBINATION METER (Click here)