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Home >> Lexus >> 2025 >> NX 350h >> Repair and Diagnosis >> External Pages >> Different car >> Section 64 (Stop And Start System - Diagnostic Codes (1 Of 2)) >> Stop And Start System >> DTC P0604-44: Internal Control Module Random Access Memory (RAM) Error Data Memory Failure [03/2023 - ] >> Procedure

DTC P0604-44: Internal Control Module Random Access Memory (RAM) Error Data Memory Failure [03/2023 - ]: Procedure

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  1. CLEAR DTC 
    1. Clear the DTCs.

      Powertrain > Stop and Start > Clear DTCs 

    2. Turn the ignition switch off.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  2

  2. READ OUTPUT DTC (DTC P0604-44) 
    1. Disconnect the cable from the negative (-) battery terminal and wait for 1 minute.
    2. Connect the cable to the negative (-) battery terminal.
    3. Turn the ignition switch to ON.
    4. Wait 16 seconds or more.
    5. Read the DTCs.

      Powertrain > Stop and Start > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output A
      DTC P0604-44 is output B

    Result: 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - ] 

    Result: 

    REPLACE ENGINE STOP AND START ECU. Refer to  REMOVAL [11/2021 - ]