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Home >> Lexus >> 2021 >> LS 500h RWD >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Airbag System (W/O Advanced Park) - Diagnostic Codes (1 Of 3) >> AIRBAG SYSTEM (w/o Advanced Park) >> DTC B1612: Front Airbag Sensor Lost Communication (RH); DTC B1613: Front Airbag Sensor RH Initialization [10/2020 - 10/2023] >> Procedure

DTC B1612: Front Airbag Sensor Lost Communication (RH); DTC B1613: Front Airbag Sensor RH Initialization [10/2020 - 10/2023]: Procedure

  1. CHECK CONNECTION OF CONNECTORS 
    1. Turn the power switch off.
    2. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 60 seconds.
    3. Check that the connectors are properly connected to the airbag ECU assembly and front airbag sensor RH.

      Result

      Proceed to
      The connectors are properly connected
      The connectors are not properly connected

    Result: 

    The connectors are not properly connected 

    CONNECT CONNECTORS PROPERLY 

    Result: 

    The connectors are properly connected 

    See step  2

  2. CHECK CONNECTORS 
    1. Disconnect the connectors from the airbag ECU assembly and front airbag sensor RH.
      GTY803715Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Airbag Sensor RH
      *2 Airbag ECU Assembly
      *3 Engine Room Main Wire
      *4 Instrument Panel Wire
    2. Check that the connectors (on the airbag ECU assembly side and front airbag sensor RH side) are not damaged.

      Result

      Proceed to
      The connectors are not deformed or damaged
      The connectors are deformed or damaged

    Result: 

    The connectors are deformed or damaged 

    REPLACE INSTRUMENT PANEL WIRE OR ENGINE ROOM MAIN WIRE 

    Result: 

    The connectors are not deformed or damaged 

    See step  3

  3. CHECK FRONT AIRBAG SENSOR RH CIRCUIT 
    1. Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
      GTY812428Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Airbag Sensor RH
      *2 Airbag ECU Assembly
      *3 Engine Room Main Wire
      *4 Instrument Panel Wire
      *5 Service Wire
      *a Front view of wire harness connector
      (to Front Airbag Sensor RH)
      *b Front view of wire harness connector
      (to Airbag ECU Assembly)
    2. Turn the power switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A26-2 (+SR) - Body ground Power switch on (IG) Below 1 V
      A26-1 (-SR) - Body ground Power switch on (IG) Below 1 V
    4. Turn the power switch off.
    5. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 60 seconds.
    6. Using a service wire, connect terminals 29 (+SR) and 28 (-SR) of connector B.
      NOTE:

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

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      A26-2 (+SR) - A26-1 (-SR) Always Below 1 Ω
    8. Disconnect the service wire from connector B.
    9. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A26-2 (+SR) - A26-1 (-SR) Always 1 MΩ or higher
      A26-2 (+SR) - Body ground Always 1 MΩ or higher
      A26-1 (-SR) - Body ground Always 1 MΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  5

    Result: 

    OK 

    See step  4

  4. CHECK FRONT AIRBAG SENSOR RH 
    1. Connect the connectors to the airbag ECU assembly.
      GTY521469Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Airbag Sensor LH
      *2 Airbag ECU assembly
    2. Interchange the front airbag sensor RH with LH and connect the connectors to them.
    3. Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
    4. Turn the power switch on (IG), and wait for at least 60 seconds.
    5. Clear the DTCs stored in memory.

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

      Body Electrical > SRS Airbag > Clear DTCs 

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

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

      Body Electrical > SRS Airbag > Trouble Codes 

      Result

      Proceed to
      DTC B1612 or B1613 is output
      DTC B1617 or B1618 is output
      DTC B1612, B1613, B1617 and B1618 are not output

      HINT: 

      Codes other than DTC B1612, B1613, B1617 and B1618 may be output at this time, but they are not related to this check.

    9. Turn the power switch off.
    10. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 60 seconds.
    11. Return the front airbag sensor LH and RH to their original positions and connect the connectors to them.

    Result: 

    DTC B1612 or B1613 is output 

    REPLACE AIRBAG ECU ASSEMBLY. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2022]  , or refer to  REMOVAL [10/2022 - 10/2023] 

    Result: 

    DTC B1617 or B1618 is output 

    REPLACE FRONT AIRBAG SENSOR RH. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2022]  , or refer to  REMOVAL [10/2022 - 10/2023] 

    Result: 

    DTC B1612, B1613, B1617 and B1618 are not output 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2020 - 11/2021]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - 10/2022]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - 10/2023] 

  5. CHECK INSTRUMENT PANEL WIRE 
    1. Disconnect the instrument panel wire connector from the engine room main wire.
      GTY818053Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Airbag Sensor RH
      *2 Airbag ECU Assembly
      *3 Engine Room Main Wire
      *4 Instrument Panel Wire
      *5 Service Wire
      *a Front view of wire harness connector
      (to Engine Room Main Wire)
      *b Front view of wire harness connector
      (to Airbag ECU Assembly)
    2. Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
    3. Turn the power switch on (IG).
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      GA 5-9 (+SR) - Body ground Power switch on (IG) Below 1 V
      GA 5-10 (-SR) - Body ground Power switch on (IG) Below 1 V
    5. Turn the power switch off.
    6. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 60 seconds.
    7. Using a service wire, connect terminals 29 (+SR) and 28 (-SR) of connector B.
      NOTE:

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

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      GA 5-9 (+SR) - GA 5-10 (-SR) 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
      GA 5-9 (+SR) - GA 5-10 (-SR) Always 1 MΩ or higher
      GA 5-9 (+SR) - Body ground Always 1 MΩ or higher
      GA 5-10 (-SR) - Body ground Always 1 MΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ENGINE ROOM MAIN WIRE 

    Result: 

    NG 

    REPLACE INSTRUMENT PANEL WIRE 

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