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Home >> Lexus >> 2019 >> LS 500 Base, RWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Anti-Theft Systems >> Smart Access System (For Start) - Diagnostic Codes (1 Of 2) >> SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function) >> DTC B2782: Power Source Control ECU Malfunction [12/2017 - 10/2020] >> Procedure
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DTC B2782: Power Source Control ECU Malfunction [12/2017 - 10/2020]: Procedure

  1. INSPECT STEERING LOCK ECU (STEERING LOCK ACTUATOR WITH ECU ASSEMBLY) (MOTOR ACTIVATION COMMAND SIGNAL) 
    1. Using an oscilloscope, check the waveform.
      GTY797118Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Steering Lock ECU (Steering Lock Actuator with ECU Assembly))
      *b Waveform
      *c Steering Lock Motor not Operating
      *d Steering Lock Motor Operating

      OK

      Tester Connection Tool Setting Condition Specified Condition
      G22-3 (IGE) - G22-1 (GND) 2 V/DIV., 200 ms./DIV. Any door opened when conditions below met, and then steering lock motor activated:
      • Shift state park (P)
      • Steering lock unlocked in advance by carrying key and turning engine switch on (IG)
      • After above conditions met, engine switch turned off
      Pulse generation
      (See waveform)

      HINT: 

      • When taking measurements when the lock motor is stopped, it is not necessary to perform any operations.
      • In order to take measurements when the lock motor is operating, perform either of the following operations:
        • To unlock the steering, carry the key and turn the engine switch on (ACC) or on (IG).
        • To lock the steering, turn the engine switch off with the shift state park (P), and then open a door.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  4

    Result: 

    OK 

    See step  2

  2. CLEAR DTC AND DATA LIST MALFUNCTION RECORD 
    1. Clear the DTCs.

      Body Electrical > Smart Access > Clear DTCs 

    2. Disconnect the cable from the negative (-) battery terminal, wait for 30 seconds or more, and then reconnect the cable to the negative (-) battery terminal to clear the record of malfunctions stored in the Data List.
      NOTE:

      After turning the engine switch off, waiting time may be required before disconnecting the cable from the battery terminal. Therefore, make sure to read the disconnecting the cable from the battery terminal notices before proceeding with work.

      Refer to PRECAUTION [12/2017 - 10/2020]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  3

  3. CHECK DTC 
    1. Perform the DTC output confirmation operation.
    2. Check if DTC B2782 is output.

      Body Electrical > Smart Access > Trouble Codes 

      Result

      Result Proceed to
      DTC B2782 is not output. A
      DTC B2782 is output. B

    Result: 

    SYSTEM RETURNED TO NORMAL (DTC STORED DUE TO BAD CONNECTION, BUT SYSTEM RETURNED TO NORMAL BY RECONNECTING CONNECTOR) 

    Result: 

    REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR WITH ECU ASSEMBLY). Refer to  DISASSEMBLY [12/2017 - 10/2022] 

  4. CHECK HARNESS AND CONNECTOR (STEERING LOCK ECU (STEERING LOCK ACTUATOR WITH ECU ASSEMBLY) - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) AND BODY GROUND) 
    1. Disconnect the G22 steering lock ECU (steering lock actuator with ECU assembly) connector.
    2. Disconnect the G71 certification ECU (smart key ECU assembly) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G22-3 (IGE) - G71-25 (SLR+) Always Below 1 Ω
      G22-1 (GND) - Body ground Always Below 1 Ω
      G22-3 (IGE) or G71-25 (SLR+) - Other terminals and body ground Always 10 kΩ or higher
      NOTE:

      If the result is not as specified, check for looseness in the connection which leads to ground.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR