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Home >> Lexus >> 2021 >> ES 250 Luxury >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Airbag System (Except Hybrid) - Diagnostic Codes (1 Of 3) >> AIRBAG SYSTEM (for Gasoline Model) >> DTC B1642: Side Satellite Sensor Bus Lost Communication (RH); DTC B1643: Side Satellite Sensor Bus Initialization Error (RH) [09/2022 - ] >> Procedure

DTC B1642: Side Satellite Sensor Bus Lost Communication (RH); DTC B1643: Side Satellite Sensor Bus Initialization Error (RH) [09/2022 - ]: Procedure

  1. CHECK CONNECTION OF CONNECTORS 
    1. Turn the engine switch off.
    2. Disconnect the cable from the negative (-) battery terminal.
      WARNING:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

    3. Check that the connectors are properly connected to the door side airbag sensor RH and airbag ECU assembly. Also check that the connectors that link the floor wire and front door wire RH are properly connected.

      OK

      The connectors are properly connected.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CONNECT CONNECTORS PROPERLY 

    Result: 

    OK 

    See step  2

  2. CHECK CONNECTORS 
    1. Disconnect the connectors from the door side airbag sensor RH and airbag ECU assembly. Also disconnect the connectors that link the floor wire and front door wire RH.
    2. Check that the terminals of the connectors are not deformed or damaged.

      OK

      The terminals are not deformed or damaged.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE FLOOR WIRE OR FRONT DOOR WIRE RH 

    Result: 

    OK 

    See step  3

  3. CHECK WIRE HARNESS 
    1. Connect the connectors that link the floor wire and front door wire RH.
      GTY1136078Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Door Side Airbag Sensor RH
      *2 Airbag ECU Assembly
      *3 Front Door Wire RH
      *4 Floor Wire
      *5 Service Wire
      *a Front view of wire harness connector
      (to Airbag ECU Assembly)
      *b Front view of wire harness connector
      (to Door Side Airbag Sensor RH)
    2. Connect the cable to the negative (-) battery terminal.
    3. Turn the engine switch on (IG).
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      J8-1 (BDR-) - Body ground Engine switch on (IG) Below 1 V
      J8-2 (BDR+) - Body ground Engine switch on (IG) Below 1 V
    5. Turn the engine switch off.
    6. Disconnect the cable from the negative (-) battery terminal.
      WARNING:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

    7. Using a service wire, connect terminals 25 (BBR+) and 26 (BBR-) of connector B.
      NOTE:

      Do not forcibly insert the service wire into the terminals of the connector when connecting the wire.

    8. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      J8-1 (BDR-) - J8-2 (BDR+) Always Below 1 Ω
    9. Disconnect the service wire from connector B.
    10. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      J8-1 (BDR-) - J8-2 (BDR+) Always 1 MΩ or higher
      J8-1 (BDR-) - Body ground Always 1 MΩ or higher
      J8-2 (BDR+) - Body ground Always 1 MΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  5

    Result: 

    OK 

    See step  4

  4. CHECK DOOR SIDE AIRBAG SENSOR RH 
    1. Connect the connector to the airbag ECU assembly.
      GTY1097299Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Door Side Airbag Sensor LH
      *2 Airbag ECU Assembly
    2. Interchange the door side airbag sensor RH with LH and connect the connectors.
    3. Connect the cable to the negative (-) battery terminal.
    4. Turn the engine switch on (IG), and wait for at least 60 seconds.
    5. Clear the DTCs stored in memory.

      Body Electrical > SRS Airbag > Clear DTCs 

    6. Turn the engine switch off.
    7. Turn the engine switch on (IG), and wait for at least 60 seconds.
    8. Check for DTCs.

      Body Electrical > SRS Airbag > Trouble Codes 

      HINT: 

      Codes other than DTCs B1642, B1643, B1647 and B1648 may be output at this time, but they are not related to this check.

      Result

      Result Proceed to
      DTC B1642 or B1643 is output. A
      DTC B1647 or B1648 is output. B
      DTCs B1642, B1643, B1647 and B1648 are not output. C
    9. Turn the engine switch off.
    10. Disconnect the cable from the negative (-) battery terminal.
      WARNING:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

    11. Return the door side airbag sensor RH and LH to their original positions and connect the connectors.

    Result: 

    A 

    REPLACE AIRBAG ECU ASSEMBLY. Refer to  REMOVAL [09/2022 - ] 

    Result: 

    B 

    REPLACE DOOR SIDE AIRBAG SENSOR RH. Refer to  REMOVAL [09/2022 - ] 

    Result: 

    C 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2018 - ] 

  5. CHECK FLOOR WIRE 
    1. Disconnect the floor wire connector from the front door wire RH.
      GTY1137551Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Door Side Airbag Sensor RH *2 Airbag ECU Assembly
      *3 Front Door Wire RH *4 Floor Wire
      *5 Service Wire - -
      *a Front view of wire harness connector
      (to Airbag ECU Assembly)      		 *b Front view of wire harness connector
      (to Front Door Wire RH)
    2. Connect the cable to the negative (-) battery terminal.
    3. Turn the engine switch on (IG).
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      JN1-10 (BDR+) - Body ground Engine switch on (IG) Below 1 V
      JN1-20 (BDR-) - Body ground Engine switch on (IG) Below 1 V
    5. Turn the engine switch off.
    6. Disconnect the cable from the negative (-) battery terminal.
      WARNING:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

    7. Using a service wire, connect terminals 25 (BBR+) and 26 (BBR-) of connector B.
      NOTE:

      Do not forcibly insert the service wire into the terminals of the connector when connecting the wire.

    8. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      JN1-10 (BDR+) - JN1-20 (BDR-) Always Below 1 Ω
    9. Disconnect the service wire from connector B.
    10. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      JN1-10 (BDR+) - JN1-20 (BDR-) Always 1 MΩ or higher
      JN1-10 (BDR+) - Body ground Always 1 MΩ or higher
      JN1-20 (BDR-) - Body ground Always 1 MΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FRONT DOOR WIRE RH 

    Result: 

    NG 

    REPLACE FLOOR WIRE 

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