ECD SYSTEM > MIL Circuit

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DESCRIPTION

The MIL (Malfunction Indicator Lamp) is used to indicate vehicle malfunctions detected 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 first turned to ON, the MIL should be illuminated and should then turn off when the engine is started. If the MIL remains illuminated or is not illuminated, conduct the following troubleshooting procedure using the intelligent tester.

WIRING DIAGRAM


A200340E01


INSPECTION PROCEDURE

1.CHECK THAT MIL IS ILLUMINATED

  1. Perform troubleshooting in accordance with the table below.
    Result 
    Result
    		Proceed to
    MIL remains on
    		A
    MIL does not illuminate
    		B



B
Go to step 5
A


2.CHECK WHETHER MIL TURNS OFF

  1. Connect the intelligent tester to the DLC3.

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

  1. Check if DTCs have been stored (Click here). If DTCs are present, write them down.

  1. Clear DTCs (Click here).

  1. Check that the MIL turns off.

    OK:
    MIL turns off.



NG
Go to step 3
OK

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS 

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

  1. Disconnect the ECM connector.

  1. Turn the ignition switch to ON.

  1. Check that MIL is not illuminated.

    OK:
    MIL is 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)


    A200339E01

  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
    D2-5 (EFI) - A19-37 (W)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    D2-5 (EFI) or A19-37 (W) - Body ground
    		Always
    		10 kΩ or higher

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

  1. Reconnect the combination meter connector.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
A

REPAIR OR REPLACE COMBINATION METER ASSEMBLY (Click here)  

5.CHECK THAT MIL IS ILLUMINATED

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

    OK:
    MIL is illuminated.



NG
Go to step 6
OK

END 

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 intelligent tester cannot communicate with the ECM.



B
GO TO VC OUTPUT CIRCUIT (Click here)
A


7.INSPECT COMBINATION METER ASSEMBLY (MIL CIRCUIT)

  1. See the combination meter troubleshooting procedure (Click here).



NG
REPLACE COMBINATION METER ASSEMBLY (Click here)
OK

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