2008 Lexus IS FFACTORY OEM SERVICE PROCEDURE

How To Proceed With Troubleshooting

HINT:

  • Use the following procedure to troubleshoot the power window control system
  • *. Use the Techstream
  1. VEHICLE BROUGHT TO WORKSHOP 
  2. CUSTOMER PROBLEM ANALYSIS 
    • 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.
      CUSTOMER PROBLEM ANALYSIS

      What Vehicle model, system name
      When Date, time, occurrence frequency
      Where Road conditions
      Under what conditions? Driving conditions, weather conditions
      How did it happen? Problem symptoms
  3. INSPECT BATTERY VOLTAGE 
    1. Measure the battery voltage

      Standard Voltage: 11 to 14 V 

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

  4. INSPECT COMMUNICATION FUNCTION OF MULTIPLEX COMMUNICATION SYSTEM (BEAN)* 
    1. Use the Techstream to check if the Multiplex Communication System (MPX) is functioning normally (See DIAGNOSTIC TROUBLE CODE CHART ).

      Result 

      RESULT REFERENCE

      Result Proceed to
      MPX DTC is output A
      MPX DTC is not output B

    A: Go to DIAGNOSTIC TROUBLE CODE CHART  (See DIAGNOSTIC TROUBLE CODE CHART )

    B: Go to next step 

  5. PROBLEM SYMPTOMS TABLE 
    1. Refer to the PROBLEM SYMPTOMS TABLE 

      Result 

      RESULT REFERENCE

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

    A: Go to step  7

    B: Go to next step 

  6. OVERALL ANALYSIS AND TROUBLESHOOTING* 
    1. Operation Check (See OPERATION CHECK  )
    2. Terminals of ECU (See TERMINALS OF ECU  )
    3. Data List/Active Test (See DATA LIST / ACTIVE TEST  )
  7. REPAIR OR REPLACE 
  8. RESET POWER WINDOW MOTOR 
    1. If the multiplex network master switch AUTO light is blinking, reset the power window regulator motor (See CUSTOMIZE PARAMETERS  )
  9. 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.

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