2011 Lexus LS 460 RWDFACTORY OEM SERVICE PROCEDURE

DTC P0604: Random Access Memory (RAM): Procedure

  1. CHECK DTC 
    1. Clear DTC. Refer to DTC CHECK / CLEAR .
    2. Turn the engine switch off.
    3. Disconnect the battery negative terminal and wait for 1 minute. Refer to PRECAUTION .
    4. Connect the battery negative terminal. Refer to PRECAUTION .
    5. Turn the engine switch on (IG).
    6. Connect the Techstream to the DLC3.
    7. Turn the Techstream on.
    8. Enter the following menus: Powertrain / Engine / Trouble Codes.
    9. Check DTC.

      OK

      P0604 is not present.

    NG → See step   3 

    OK → See step   2 

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

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.