ECD SYSTEM MIL Circuit

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 GTS.

WIRING DIAGRAM

A01QQL9E09
*a METER
*b from IG2 Relay
*c Combination Meter

CAUTION / NOTICE / HINT

Note

After replacing the ECM, the new ECM needs registration (Click here ) and initialization Click here.

PROCEDURE


  1. CHECK THAT MIL IS ILLUMINATED


    1. Perform troubleshooting in accordance with the table below.

      Result
      Proceed to
      MIL remains on
      MIL does not illuminate

    MIL does not illuminate

    CHECK THAT MIL IS ILLUMINATED Click here

    MIL remains on

  2. CHECK WHETHER DTC OUTPUT RECURS


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine / Trouble Codes.


      Powertrain > Engine and ECT > Trouble Codes

    5. Check if any DTCs have been detected. Note down any DTCs.

      Result
      Proceed to
      No DTC detected
      Any DTCs detected

      Tech Tips

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


    Any DTCs detected

    REPAIR CIRCUITS INDICATED BY OUTPUT DTCS Click here

    No DTC detected

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


    1. Disconnect the A61 ECM connector.

    2. Turn the ignition switch to ON.

    3. Check that the MIL is not illuminated.

      OK
      MIL is not illuminated.
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

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


    1. Disconnect the combination meter assembly connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G16-11 (CHK) or A61-12 (W) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  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.
      Result
      Proceed to
      OK
      NG

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

    NG

  6. CHECK THAT ENGINE STARTS


    1. Turn the ignition switch to ON.

    2. Start the engine.

      Result
      Proceed to
      Engine starts
      Engine does not start*

      Tech Tips

      *: The GTS cannot communicate with the ECM.


    Engine does not start*

    GO TO VC OUTPUT CIRCUIT Click here

    Engine starts

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


    1. Disconnect the combination meter assembly connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G16-11 (CHK) - A61-12 (W) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR