Lexus IS250 · Service Manual BODY ELECTRICAL

HOW TO PROCEED WITH TROUBLESHOOTING

Troubleshooting

HINT:
  1. Use the following procedures to troubleshoot the entry and start system.
  2. The intelligent tester can be used in steps 4 and 6.
  3. When troubleshooting the entry and start system using the intelligent tester with the engine switch off, connect the intelligent tester to the vehicle and repeat turning any of the courtesy light switches on and off until communication between the tester and the vehicle begins (the interval ON and OFF should be less than 1.5 sec.).


1.VEHICLE BROUGHT TO WORKSHOP
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    2.CUSTOMER PROBLEM ANALYSIS CHECK

      HINT:
      1. 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.
      2. Gather as much information as possible for reference. Past problems that seem unrelated may also help in some cases.
      3. 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

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    3.INSPECT 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.
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    4.INSPECT COMMUNICATION FUNCTION OF MULTIPLEX COMMUNICATION SYSTEM (BEAN)

    1. Use the intelligent tester to check if the Multiplex Communication System (MPX) is functioning normally (Click here).

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


    		B.
    A

    5.CHECK FOR DTC

    1. Check for DTCs and note any codes that are output (Click here).

    2. Delete the DTCs.

    3. Recheck for DTCs.

      4. Result:
      Result
      		 Proceed to
      DTC does not reoccur
      		 A
      DTC reoccurs
      		 B


    		B.
    A

    6.PROBLEM SYMPTOMS TABLE
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      7.OVERALL ANALYSIS AND TROUBLESHOOTING

      1. On-vehicle inspection (Click here)

      2. DATA LIST/ACTIVE TEST (Click here)

      3. Terminals of ECU (Click here)

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      8.REPAIR OR REPLACEMENT
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        9.CONFIRMATION TEST
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