ECD SYSTEM (for CCo) 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 intelligent tester.

WIRING DIAGRAM

A01IPNME05

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. CHECK THAT MIL IS ILLUMINATED


    1. Check the MIL illumination condition.

      Result
      Condition Proceed to
      MIL remains on A
      MIL does not illuminate B

    B
    A
  2. CHECK WHETHER MIL TURNS OFF


    1. Connect the intelligent tester to the DLC3.

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

    3. Check if DTCs have been stored Click here. If DTCs are output, write them down.

    4. Clear DTCs Click here.

    5. Check that the MIL turns off.

      Standard
      MIL turns off.

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

    A01ITNTE09
    Text in Illustration
    *1

    Front view of wire harness connector

    (to ECM)


    1. Disconnect the ECM connector.

    2. Turn the ignition switch to ON.

    3. Check that the MIL is not illuminated.

      OK
      MIL is not illuminated.
    4. Reconnect the ECM connector.


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

    A01ITJIE54
    Text in Illustration
    *1

    Front view of wire harness connector

    (to Combination Meter)

    *2

    Front view of wire harness connector

    (to ECM)


    1. Disconnect the ECM connector.

    2. Disconnect the combination meter connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      H62-29 (EFI) - A51-12 (W) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      H62-29 (EFI) or A51-12 (W) - Body ground Always 10 kΩ or higher
    4. Reconnect the ECM connector.

    5. Reconnect the combination meter connector.


    NG
    OK
  5. CHECK THAT MIL IS ILLUMINATED


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

      OK
      MIL is illuminated.

    NG
    OK
  6. CHECK THAT ENGINE STARTS


    1. Turn the ignition switch to ON.

    2. Start the engine.

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

      Tech Tips

      *: The intelligent tester cannot communicate with the ECM.


    B
    A
  7. INSPECT COMBINATION METER ASSEMBLY (MIL CIRCUIT)


    1. See the combination meter troubleshooting procedure Click here.

      Result
      Result Proceed to
      NG A
      OK B

    B
    A