How To Proceed With Troubleshooting

2010 Lexus RX 450h 3.5 BSECTION How To Proceed With Troubleshooting

HINT: 

  • Use the following procedure to troubleshoot the smart access system with push-button start.
  • *: Use the Techstream.
  1. VEHICLE BROUGHT TO WORKSHOP 

    NEXT: Go to next step 

  2. CUSTOMER PROBLEM ANALYSIS 

    HINT: 

    • In troubleshooting, confirm that the problem symptoms have been accurately identified. Preconceptions should be discarded in order to make an accurate judgment. To clearly understand what the problem symptoms are, it is extremely important to ask the customer about the problem and the conditions at the time the malfunction occurred.
    • Gather as much information as possible for reference. Past problems that seem unrelated may also help in some cases.
    • The following 5 items are important points in the problem analysis:
    What Vehicle model, system name
    When Date, time, occurrence frequency
    Where Road conditions
    Under what conditions? Running conditions, driving conditions, weather conditions
    How did it happen? Problem symptoms

    NEXT: Go to next step 

  3. INSPECT BATTERY VOLTAGE 
    1. Measure the battery voltage with the power switch off.

      Standard Voltage

      11 to 14 V

      If the voltage is below 11 V, recharge or replace the battery before proceeding to the next step.

      NEXT: Go to next step 

  4. INSPECT COMMUNICATION FUNCTION OF CAN COMMUNICATION SYSTEM* 
    1. Use the Techstream to check if the CAN communication system is functioning normally.

      Result

      Result Proceed to
      ECU connected, communication line is normal. A
      ECU connected, communication line is malfunctioning. B

      B → GO TO CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING 

      A: Go to next step 

  5. INSPECT COMMUNICATION FUNCTION OF LIN COMMUNICATION SYSTEM (LIN)* 
    1. Use the Techstream to check if the LIN communication system (LIN) is functioning normally. Refer to DTC CHECK / CLEAR .

      Result

      Result Proceed to
      LIN DTC is not output. A
      LIN DTC is output. B

      B → GO TO LIN COMMUNICATION SYSTEM. Refer to  DIAGNOSTIC TROUBLE CODE CHART 

      A: Go to next step 

  6. CHECK FOR DTC* 
    1. Check for DTCs and note any codes that are output.
    2. Clear the DTCs.
    3. Recheck for DTCs. Based on the DTCs output, try to cause the same steering lock system DTC, engine immobiliser system DTC, wireless door lock control system DTC or smart access system with push-button start (for start function) DTC to be output by simulating the symptoms indicated by the DTCs.

      Result

      Result Proceed to
      DTC is not output. A
      Steering lock system DTC is output. B
      Engine immobiliser system DTC is output. C
      Wireless door lock control system DTC is output. D
      Smart access system with push-button start (for start function) DTC is output. E

      B → GO TO STEERING LOCK SYSTEM. Refer to  DIAGNOSTIC TROUBLE CODE CHART 

      C → GO TO ENGINE IMMOBILISER SYSTEM. Refer to  DIAGNOSTIC TROUBLE CODE CHART 

      D → GO TO WIRELESS DOOR LOCK CONTROL SYSTEM SYSTEM. Refer to  DIAGNOSTIC TROUBLE CODE CHART 

      E → GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function). Refer to  HOW TO PROCEED WITH TROUBLESHOOTING 

      A: Go to next step 

  7. CHECK KEY 
    1. Confirm that the entry function operates normally for all registered keys. Refer to OPERATION CHECK .

      HINT: 

      For vehicles with a key (for card type), confirm operation of both the key (for card type) and keys (for standard).

      NEXT: Go to next step 

  8. PROBLEM SYMPTOMS TABLE 
    1. Refer to Problem Symptoms Table. Refer to PROBLEM SYMPTOMS TABLE .

      Result

      Result Proceed to
      Fault is not listed in Problem Symptoms Table. A
      Fault is listed in Problem Symptoms Table. B

      B → Go to step   10 . 

      A: Go to next step 

  9. OVERALL ANALYSIS AND TROUBLESHOOTING* 
    1. Operation Check. Refer to OPERATION CHECK 
    2. Data List / Active Test. Refer to DATA LIST / ACTIVE TEST 
    3. Terminal Connector Identification. Refer to TERMINAL CONNECTOR IDENTIFICATION 

      NEXT: Go to next step 

  10. REPAIR OR REPLACEMENT 

    NEXT: Go to next step 

  11. CONFIRMATION TEST 

    NEXT → END 

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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.