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Home >> Lexus >> 2020 >> ES 300h Luxury >> Repair and Diagnosis >> External Pages >> Different car >> Section 33 (Lin Communication System (Except Hybrid) - Diagnostic Codes) >> LIN COMMUNICATION SYSTEM (for Gasoline Model) >> DTC B2785: Communication Malfunction between ECUs Connected by LIN [06/2018 - 09/2022] >> Procedure

DTC B2785: Communication Malfunction between ECUs Connected by LIN [06/2018 - 09/2022]: Procedure

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  1. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - EACH ECU) 
    1. Disconnect the G47 certification ECU (smart key ECU assembly) connector.
    2. Disconnect the G51 steering lock ECU (steering lock actuator or upper bracket assembly) connector.
    3. Disconnect the G52 ID code box (immobiliser code ECU) connector.
    4. Measure the resistance according to the value(s) in the table below.
      NOTE:

      Make sure that each ECU is in sleep mode before performing the inspection. To enter sleep mode, turn the engine switch from on (IG) to off and wait for 180 seconds or more without operating any switches.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G47-13 (LIN) - G51-5 (LIN) Engine switch off Below 1 Ω
      G47-13 (LIN) - G52-2 (LIN1) Engine switch off Below 1 Ω
      G47-13 (LIN), G51-5 (LIN) or G52-2 (LIN1) - Body ground Engine switch off 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  2

  2. CHECK FOR DTC (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)) 
    1. Connect the G47 certification ECU (smart key ECU assembly) connector.
    2. Connect the G52 ID code box (immobiliser code ECU) connector.
    3. Clear the DTCs.

      Body Electrical > Smart Access > Clear DTCs 

    4. Recheck for DTCs.

      Body Electrical > Smart Access > Trouble Codes 

      Result

      Result Proceed to
      DTC B2785 is output A
      DTC B2785 is not output B

    Result: 

    B 

    REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY). Refer to  DISASSEMBLY [06/2018 - 09/2022] 

    Result: 

    A 

    See step  3

  3. CHECK FOR DTC (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)) 
    1. Connect the G51 steering lock ECU (steering lock actuator or upper bracket assembly) connector.
    2. Disconnect the G52 ID code box (immobiliser code ECU) connector.
    3. Clear the DTCs.

      Body Electrical > Smart Access > Clear DTCs 

    4. Recheck for DTCs.

      Body Electrical > Smart Access > Trouble Codes 

      Result

      Result Proceed to
      DTC B2785 is output A
      DTC B2785 is not output B

    Result: 

    A 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 

    Result: 

    B 

    REPLACE ID CODE BOX (IMMOBILISER CODE ECU) 

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