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Home >> Lexus >> 2012 >> LS 460 AWD >> Repair and Diagnosis >> Electrical >> Starter >> Smart Access System With Push-Button Start (Diagnostic Codes & Symptom Tests) >> Smart Access System With Push-Button Start >> Symptom Tests >> Engine does not Start >> Procedure
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Engine does not Start: Procedure

  1. CHECK WHETHER ENGINE STARTS AFTER STEERING LOCK INITIALIZATION 
    1. Open and close the driver door when the engine switch is off.
    2. Check that the engine starts.

      OK

      Engine starts.

      HINT: 

      After the battery runs out, the engine may not start if the steering lock ECU has not been initialized (lock/unlock may not be recorded) through the procedure described above.

    OK → SYSTEM OK 

    NG: Go to next step 

  2. CHECK WHETHER DTC OUTPUT RECURS (MAIN BODY ECU AND CERTIFICATION ECU) 
    1. Clear the DTCs. Refer to DTC CHECK/CLEAR .

      HINT: 

      After all DTCs are cleared, check if the trouble occurs again 5 seconds after the engine switch is turned on (IG).

    2. Check for DTCs again.

      OK

      No DTC is output.

    NG → See step   12 

    OK: Go to next step 

  3. CHECK ENGINE SWITCH (SWITCH CONDITION) 
    1. Ensure the key is inside the cabin.
    2. With the brake pedal released, check that the power source mode changes as shown below each time the engine switch is pushed.

      OK

      off → on (ACC) → on (IG) → off

    NG → See step   13 

    OK: Go to next step 

  4. CHECK BASIC FUNCTION 
    1. Ensure that there is fuel in the fuel tank and the key is inside the cabin.
    2. Depress the brake pedal with the shift lever in P or N, and keep depressing the pedal.
    3. Check that the engine cranks when the engine switch is pressed.

      OK

      Engine cranks.

    OK → See step   9 

    NG: Go to next step 

  5. READ VALUE USING TECHSTREAM (PARK/NEUTRAL POSITION SWITCH) 
    1. Use the Data List to check if the park / neutral position switch is functioning properly.
      MAIN BODY

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Neutral SW/Clutch SW Park/neutral position switch/ON or OFF ON: Shift lever in P or N
      OFF: Shift lever in R or D
      -

      OK

      When the shift lever is in P or N, ON is displayed on the Techstream.

    NG → See step   15 

    OK: Go to next step 

  6. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH) 
    1. Use the Data List to check if the stop light switch is functioning properly.
      MAIN BODY

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Stop Light SW Stop Light switch/ON or OFF ON: Brake pedal depressed
      OFF: Brake pedal released
      -

      OK

      When the brake pedal is depressed, ON is displayed on the Techstream.

    NG → See step   10 

    OK: Go to next step 

  7. CHECK STEERING LOCK SYSTEM 
    1. When the engine switch is on (ACC), check that the steering lock can be released.

      OK

      Steering lock can be released.

    NG → See step   14 

    OK: Go to next step 

  8. INSPECT MAIN BODY ECU 
    1. Disconnect the A68 main body ECU connector.
      Fig 1: Identifying A68 Main Body ECU Connector
      GTY288072Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Depress the brake pedal with the shift lever in P or N, and keep depressing the pedal.
    3. Measure the voltage according to the value(s) in the table below.

      Standard voltage

      Tester Connection Condition Specified Condition
      A68-4 (STSW) - Body ground When the engine cranks by pressing the engine switch. 11 to 14 V

    NG → See step   11 

    OK → REPLACE MAIN BODY ECU 

  9. READ VALUE USING TECHSTREAM (ENGINE START REQUEST) 
    1. Use the Data List to check if the engine start request is functioning properly.
      SMART ACCESS

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Engine Start Request (Past) Starter request signal/OK or NG (Past) OK: ID code box receives immobilizer unset signal
      NG (Past): ID code box does not receive immobilizer unset signal
      -

      OK

      When ID code box receives immobilizer unset signal, OK is displayed on the Techstream.

    NG → REPLACE CERTIFICATION ECU 

    OK → REPLACE ID CODE BOX 

  10. REPAIR OR REPLACE STOP LIGHT SWITCH. Refer to  REMOVAL 
  11. GO TO SFI SYSTEM (CRANKING HOLDING FUNCTION CIRCUIT). Refer to  HOW TO PROCEED WITH TROUBLESHOOTING 
  12. GO TO DTC TABLE. Refer to  DIAGNOSTIC TROUBLE CODE TABLE 
  13. GO TO POWER SOURCE MODE DOES NOT CHANGE. Refer to  Power Source Mode does not Change  
  14. GO TO STEERING LOCK SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING 
  15. REPAIR OR REPLACE PARK/NEUTRAL POSITION SWITCH. Refer to  REMOVAL