2011 Lexus IS 350CFACTORY OEM SERVICE PROCEDURE

DTC P0604: Internal Control Module Random Access Memory (RAM) Error: Procedure

  1. READ DTC OUTPUT (DTC P0604) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Clear the DTCs. Refer to DTC CHECK / CLEAR .
    5. Turn the engine switch off.
    6. Turn the Techstream off.
    7. Disconnect the Techstream.
    8. Disconnect the cable from the negative (-) battery terminal and wait for 1 minute.
    9. Connect the cable to the negative (-) battery terminal.
    10. Connect the Techstream to the DLC3.
    11. Turn the engine switch on (IG).
    12. Turn the Techstream on.
    13. Wait 16 seconds or more.
    14. Enter the following menus: Powertrain / Engine / Trouble Codes.
    15. Read the DTCs.

      Result

      Result Proceed to
      DTC is not output A
      DTC P0604 is output B

    B → See step   3 

    A → See step   2 

  2. CHECK FOR INTERMITTENT PROBLEMS. Refer to  CHECK FOR INTERMITTENT PROBLEMS 
  3. REPLACE ECM. Refer to  REMOVAL 
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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.