LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2011 >> IS 250C Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (4GR-FSE) (Diagnostic Codes & Circuit Tests) >> SFI System >> Circuit Tests >> MIL Circuit >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

MIL Circuit: Procedure

  1. CHECK THAT MIL ILLUMINATES 
    1. Turn the engine switch on (IG).
    2. Check the illumination of the MIL.

      Result

      Result Proceed to
      MIL remains illuminated (Even after engine switch is turned on (IG) and several seconds have passed, MIL still remains illuminated) A
      MIL remains off (Does not illuminate at all) B
      MIL illuminates for several seconds, but turns off after engine is started C

    B → See step   5 

    C → SYSTEM OK 

    A: Go to next step 

  2. CHECK WHETHER MIL TURNS OFF 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine / Trouble Codes.
    5. Check if any DTCs have been stored. Note any DTCs.
    6. Clear the DTCs. Refer to DTC CHECK / CLEAR .
    7. Check if the MIL goes off.

      Result

      Result Proceed to
      MIL goes off A
      MIL does not go off B

    B → See step   3 

    A → See step   8 

  3. CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS) 
    1. Disconnect the ECM connector.
      Fig 1: ECM Connector
      GTY352299Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Turn the engine switch on (IG).
    3. Check if the MIL is illuminated.

      Result

      Result Proceed to
      MIL is not illuminated A
      MIL is illuminated B
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to ECM)
    4. Reconnect the ECM connector.

    B → See step   4 

    A → See step   9 

  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 (Check for Short)

      Tester Connection Condition Specified Condition
      J35-12 (EFI) or A6-8 (W) - Body ground Always 10 kΩ or higher
    4. Reconnect the combination meter assembly connector.
    5. Reconnect the ECM connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   10 

  5. CHECK IF ENGINE STARTS 
    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 → See step   11 

    A: Go to next step 

  6. CHECK HARNESS AND CONNECTOR (ECM TERMINAL VOLTAGE) 
    1. Disconnect the ECM connector.
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A6-8 (W) - Body ground Engine switch on (IG) 11 to 14 V
    4. Reconnect the ECM connector.

    NG → See step   7 

    OK → See step   9 

  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 (Check for Open)

      Tester Connection Condition Specified Condition
      J35-12 (EFI) - A6-8 (W) Always Below 1 Ω
    4. Reconnect the ECM connector.
    5. Reconnect the combination meter assembly connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   12 

  8. REPAIR CIRCUIT INDICATED BY OUTPUT DTC. Refer to  DIAGNOSTIC TROUBLE CODE CHART 
  9. REPLACE ECM. Refer to  REMOVAL 
  10. REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL 
  11. GO TO VC OUTPUT CIRCUIT. Refer to  VC Output Circuit  
  12. REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL