2002 Lexus SC 430FACTORY OEM SERVICE PROCEDURE

How To Proceed With Troubleshooting

WARNING: This page is about a different car, the 2004 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

  • Use this procedure to troubleshoot the smart key system.
  • The hand-held tester should be used in step 3 and 5.
  1. VEHICLE BROUGHT TO WORKSHOP 
  2. CUSTOMER PROBLEM ANALYSIS CHECK AND SYMPTOM CHECK (See  CUSTOMER PROBLEM ANALYSIS CHECK  ) 
  3. INSPECT COMMUNICATION FUNCTION OF LARGE-SCALE MULTIPLEX COMMUNICATION SYSTEM (BEAN) 
    1. Use the hand-held tester to check for normal function of the multiplex communication system.
      1. (ECU unconnected, communication line malfunctioning) Without code outputs, proceed to A.
      2. (ECU unconnected, communication line malfunctioning) With code outputs, proceed to B.

    B: Go to MULTIPLEX COMMUNICATION SECTION (SEE  DIAGNOSTIC TROUBLE CODE CHART  ) 

    A: Go to next step 

  4. DTC CHECK (See  DTC CHECK/CLEAR  ) 
    1. Check for DTC and note any codes that are output.
    2. Delete the DTC.
    3. Recheck for DTCs. Try to prompt the DTC by simulating the original activity that the DTC suggests.
      1. If the DTC does not reoccur, proceed to A.
      2. If the DTC reoccurs, proceed to B

    B: Go to step 6 

    A: Go to next step 

  5. PERFORM SYMPTOM TABLE (See  PROBLEM SYMPTOMS TABLE  ) 
    1. If the fault is not listed on the problem symptoms table, proceed to A.
    2. If the fault is listed on the problem symptoms table, proceed to B.

    B: Go to step 7 

    A: Go to next step 

  6. OVERALL ANALYSIS AND TROUBLE SHOOTING 
    1. DATA LIST/ACTIVE TEST (see DATA LIST/ACTIVE TEST )
      1. Inspection with the hand-held tester (DATA LIST).
      2. Inspection with the hand-held tester (ACTIVE TEST).
    2. Terminals of ECU (see TERMINALS OF ECU )
    3. On-vehicle inspection (see ON-VEHICLE INSPECTION )
    4. Inspection (see INSPECTION )
  7. ADJUST, REPAIR OR REPLACE 
  8. CONFIRMATION TEST 

    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.