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MIL Circuit: 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 → See step   5 

    A: Go to next step 

  2. CHECK WHETHER MIL TURNS OFF 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
    5. Check if any DTCs have been detected. Note down any DTCs.
      RESULT

      Result Proceed to
      No DTC detected A
      Any DTCs detected B

      HINT: 

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

    B → See step   8 

    A: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS) 
    Fig 1: Identifying ECM Connector
    GTY166245Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    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 → See step   4 

    OK → See step   9 

  4. CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM) 
    Fig 2: Identifying Combination Meter And ECM Connector Terminals
    GTY313873Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    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 Short)

      Tester Connection Condition Specified Condition
      A21-24 (W) or F1-9 (EFI) - Body ground Always 10 kΩ or higher
    4. Reconnect the ECM connector.
    5. Reconnect the combination meter connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   12 

  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 → See step   6 

    OK → See step   11 

  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

      HINT: 

      *: The Techstream cannot communicate with the ECM.

    B → See step   13 

    A: Go to next step 

  7. CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM) 
    Fig 3: Identifying Combination Meter And ECM Connector Terminals
    GTY313873Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    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
      A21-24 (W) - F1-9 (EFI) Always Below 1 Ω
    4. Reconnect the ECM connector.
    5. Reconnect the combination meter connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   10 

  8. REPAIR CIRCUITS INDICATED BY OUTPUT DTCS. Refer to  DIAGNOSTIC TROUBLE CODE CHART 
  9. REPLACE ECM. Refer to  REMOVAL 
  10. REPLACE COMBINATION METER. Refer to  REMOVAL 
  11. CHECK FOR INTERMITTENT PROBLEMS. Refer to  CHECK FOR INTERMITTENT PROBLEMS 
  12. REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL 
  13. GO TO VC OUTPUT CIRCUIT. Refer to  VC Output Circuit