2004 Lexus SC 430FACTORY OEM SERVICE PROCEDURE

How To Proceed With Troubleshooting

  1. VEHICLE BROUGHT TO WORKSHOP 
  2. (See CUSTOMER PROBLEM ANALYSIS CHECK AND SYMPTOM CHECK )
  3. INSPECT COMMUNICATION FUNCTION OF LARGE-SCALE BODY MULTIPLEX COMMUNICATION SYSTEM (BEAN) 
    1. Check that there is no abnormality in the communication system by inspecting the communication function of the body multiplex communication system with the hand-held tester.
      1. (ECU unconnected, communication line abnormal) Without code output, proceed to A.
      2. (ECU unconnected, communication line abnormal) With code output, proceed to B.
    1. A: Go to step   4 . 
    2. B: Go to MULTIPLEX COMMUNICATION SYSTEM (See  HOW TO PROCEED WITH TROUBLESHOOTING  ) 
  4. See DIAGNOSTIC TROUBLE CODE CHECK .
    1. Check a DTC and note it if a code is output.
    2. Delete the DTC.
    3. Check if the DTC will be output once again, when the problem symptom is simulated based on the noted code.
      1. Without an output of the code, proceed to A.
      2. With an output of the code, proceed to B.
    1. A: Go to step   5 . 
    2. B: Go to step   7 
  5. See PROBLEM SYMPTOMS TABLE .
    1. Without an applicable symptoms table, proceed to A.
    2. With an applicable symptoms table, proceed to B.
    1. A: Go to step   6 . 
    2. B: Go to step   7 . 
  6. ACCORDING TO PROBLEM SYMPTOM, PERFORM TROUBLESHOOTING 
    1. See PRE-CHECK .
    2. See TERMINALS OF ECU .
  7. ADJUST, REPAIR OR REPLACE 

    END 

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

Shop Manual-Ready ToolsCompare Repair QuoteQuote Shield Pro

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.