LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2009 >> SC 430 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostic Codes (P0351-U0001) - Circuit Tests) >> SFI System >> MIL Circuit >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

MIL Circuit: Procedure

  1. CHECK THAT MIL IS ILLUMINATED 
    1. Perform troubleshooting in accordance with the chart below.

      Result

      Condition Proceed to
      MIL remains on A
      MIL is not illuminated B

    B → See step   5 

    A: Go to next step 

  2. CHECK IF MIL TURNS OFF 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch ON and turn the tester ON.
    3. Check if DTCs have been stored. Refer to DIAGNOSTIC TROUBLE CODE CHART . If DTCs are present, write them down.
    4. Clear the DTCs. Refer to DTC CHECK / CLEAR .
    5. Check that the MIL turns off.

      OK

      MIL turns off.

    OK → REPAIR CIRCUITS INDICATED BY OUTPUT DTCS 

    NG: Go to next step 

  3. CHECK WIRE HARNESS (FOR SHORT) 
    Fig 1: Identifying E5 ECM Connector
    GTY144283Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the E5 ECM connector.
    2. Turn the ignition switch ON.
    3. Check that the MIL is not illuminated.

      OK

      MIL is not illuminated.

    OK → REPLACE ECM 

    NG: Go to next step 

  4. CHECK WIRE HARNESS (COMBINATION METER - ECM) 
    Fig 2: Checking Wire Harness (Combination Meter - ECM)
    GTY131970Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the C8 combination meter connector.
    2. Disconnect the E5 ECM connector.
    3. Measure the resistance of the wire harness side connectors.

      Standard resistance

      Tester Connection Specified Condition
      C8-6 (CHK) - E5-8 (W) Below 1 Ω
      C8-6 (CHK) or E5-8 (W) - Body ground 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS AND CONNECTOR 

    OK → REPAIR OR REPLACE COMBINATION METER 

  5. CHECK THAT MIL IS ILLUMINATED 
    1. Check that the MIL is illuminated when turning the ignition switch ON.

      OK

      MIL is illuminated.

    OK → SYSTEM OK 

    NG: Go to next step 

  6. CHECK THAT ENGINE STARTS 
    1. Turn the ignition switch 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 → GO TO VC OUTPUT CIRCUIT 

    A: Go to next step 

  7. CHECK WIRE HARNESS (COMBINATION METER - BODY GROUND) 
    Fig 3: Identifying E5 ECM Connector
    GTY144283Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the E5 ECM connector.
    2. Turn the ignition switch ON.
    3. Measure the voltage of the wire harness side connectors

      Standard voltage

      Tester Connection Specified Condition
      E5-8 (W) - Body ground 11 to 14 V

    OK → REPLACE ECM 

    NG: Go to next step 

  8. CHECK WIRE HARNESS (COMBINATION METER - ECM) 
    Fig 4: Checking Wire Harness (Combination Meter - ECM)
    GTY131970Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the C8 combination meter connector.
    2. Disconnect the E5 ECM connector.
    3. Measure the resistance of the wire harness side connectors.

      Standard resistance

      Tester Connection Specified Condition
      C8-6 (CHK) - E5-8 (W) Below 1 Ω
      C8-6 (CHK) or E5-8 (W) - Body ground 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS AND CONNECTOR 

    OK → REPAIR OR REPLACE COMBINATION METER 

scientia non olet · About LEMON Manuals