2006 Scion tC AutomaticFACTORY OEM SERVICE PROCEDURE

MIL Circuit: Wiring Diagram

Fig 1: MIL Circuit - Wiring Diagram
G04221317Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  1. CHECK THAT MIL IS ILLUMINATED 
    1. Perform troubleshooting in accordance with the chart below.

      Result 

    RESULT CHART

    Condition Proceed to
    MIL remains illuminated A
    MIL not illuminated B

    B : GO TO STEP   4 

    A : Go to next step 

  2. CHECK WHETHER MIL TURNS OFF 
    1. Connect the intelligent tester to the DLC3.
    2. Turn the ignition switch ON.
    3. Turn the tester ON.
    4. Check whether any DTCs have been stored (see DTC CHECK / CLEAR  ). Note them down if necessary.
    5. Clear DTCs (see DTC CHECK / CLEAR  ).
    6. Check if the MIL turns off.

    OK: 

    MIL should turn off. 

    OK : REPAIR CIRCUIT INDICATED BY OUTPUT DTC 

    NG 

  3. CHECK WIRE HARNESS (FOR SHORT) 
    1. Disconnect the E4 ECM connector.
    2. Turn the ignition switch ON.
    3. Check that the MIL is not illuminated.

    OK: 

    MIL is not illuminated 

    OK : REPLACE ECM 

    Fig 2: Disconnecting E4 ECM Connector
    G04221318Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG : CHECK AND REPAIR HARNESS AND CONNECTOR (COMBINATION METER - ECM) 

  4. CHECK THAT MIL IS ILLUMINATED 
    1. Check if the MIL is illuminated when the ignition switch is turned ON.

    OK: 

    MIL should be illuminated. 

    OK : SYSTEM OK 

    NG 

  5. CHECK THAT ENGINE STARTS 
    1. Turn the ignition switch ON.
    2. Start the engine.
    RESULT CHART

    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 

    A : Go to next step 

  6. INSPECT COMBINATION METER (MIL CIRCUIT) 
    1. See the combination meter troubleshooting procedure (see HOW TO PROCEED WITH TROUBLESHOOTING ).

    NG : REPAIR OR REPLACE BULB OR COMBINATION METER ASSEMBLY 

    OK : CHECK AND REPAIR HARNESS AND CONNECTOR (COMBINATION METER - ECM) 

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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