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Home >> Lexus >> 2021 >> LS 500h RWD >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System - Diagnostic Codes (P050B - P060E) >> SFI System >> DTC P0604-44: Internal Control Module Random Access Memory (RAM) Error Data Memory Failure [10/2020 - 11/2021] >> Caution / Notice / Hint
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Caution / Notice / Hint

NOTE:
  • Vehicle Control History may be stored in the hybrid vehicle control ECU if the engine is malfunctioning. Certain vehicle condition information is recorded when Vehicle Control History is stored. Reading the vehicle conditions recorded in both the freeze frame data and Vehicle Control History can be useful for troubleshooting.

    w/ Advanced Park:

    w/o Advanced Park: Refer to VEHICLE CONTROL HISTORY [10/2020 - 11/2021]

    (Select Powertrain in Health Check and then check the time stamp data.)

    Refer to DTC CHECK / CLEAR [10/2020 - 10/2023]

  • If any "Engine Malfunction" Vehicle Control History item has been stored in the hybrid vehicle control ECU, make sure to clear it. However, as all Vehicle Control History items are cleared simultaneously, if any Vehicle Control History items other than "Engine Malfunction" are stored, make sure to perform any troubleshooting for them before clearing Vehicle Control History.

    w/ Advanced Park:

    w/o Advanced Park: Refer to VEHICLE CONTROL HISTORY [10/2020 - 11/2021]

  • After the power switch off, there may be a waiting time before disconnecting the negative (-) auxiliary battery terminal.

    Refer to BEFORE DISCONNECTING BATTERY [10/2020 - 11/2021]

  • When disconnecting and reconnecting the auxiliary battery.

    Refer to WORK PROCEDURE [10/2020 - 11/2021]

    HINT: 

    When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.

    Refer to AUTOMATIC LEARNING CHART [10/2020 - 11/2021]

HINT: 

Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.