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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Airbag System - Diagnostic Codes (6 Of 7) >> Airbag System >> DTC B1638: Curtain Shield Airbag Sensor Initialization Error (LH) [12/2019 - 11/2023] >> Procedure

DTC B1638: Curtain Shield Airbag Sensor Initialization Error (LH) [12/2019 - 11/2023]: Procedure

  1. CHECK HISTORY DTC 
    1. Check for history DTCs.

      Body Electrical > SRS Airbag > Trouble Codes 

      HINT: 

      Codes other than history DTC B1637 may be output at this time, but they are not related to this check.

      Result

      Result Proceed to
      History DTC B1637 is not output. A
      History DTC B1637 is output. B

    Result: 

    B 

    GO TO DTC B1637. Refer to  DTC B1635: Curtain Shield Airbag Sensor (LH); DTC B1637: Curtain Shield Airbag Sensor Lost Communication (LH) [12/2019 - 11/2023]  

    Result: 

    A 

    See step  2

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

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

    3. Check that the connectors are properly connected to the airbag sensor assembly, side airbag sensor assembly LH and rear airbag sensor LH. Also check that the connectors that link the No. 2 floor wire and front door wire LH are properly connected.

      OK

      The connectors are properly connected.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CONNECT CONNECTORS PROPERLY 

    Result: 

    OK 

    See step  3

  3. CHECK CONNECTORS 
    1. Disconnect the connectors from the airbag sensor assembly, side airbag sensor assembly LH and rear airbag sensor LH. Also disconnect the connectors that link the No. 2 floor wire and front door wire LH.
    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 NO. 2 FLOOR WIRE OR FRONT DOOR WIRE LH 

    Result: 

    OK 

    See step  4

  4. CHECK NO. 2 FLOOR WIRE 
    1. Connect the cable to the negative (-) auxiliary battery terminal.
      GTY928912Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Airbag Sensor LH
      *2 Airbag Sensor Assembly
      *3 No. 2 Floor Wire
      *4 Service Wire
      *a Front view of wire harness connector
      (to Airbag Sensor Assembly)
      *b Front view of wire harness connector
      (to Rear Airbag Sensor LH)
    2. Turn the ignition switch to ON.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      M62-4 (BCL+) - Body ground Ignition switch ON Below 1 V
      M62-3 (BCL-) - Body ground Ignition switch ON Below 1 V
    4. Turn the ignition switch off.
    5. Disconnect the cable from the negative (-) auxiliary battery terminal.
      WARNING:

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

    6. Using a service wire, connect terminals 32 (BBL+) and 31 (BBL-) of connector B.
      NOTE:

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

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      M62-4 (BCL+) - M62-3 (BCL-) 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
      M62-4 (BCL+) - M62-3 (BCL-) Always 1 MΩ or higher
      M62-4 (BCL+) - Body ground Always 1 MΩ or higher
      M62-3 (BCL-) - Body ground Always 1 MΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE NO. 2 FLOOR WIRE 

    Result: 

    OK 

    See step  5

  5. CHECK WIRE HARNESS 
    1. Connect the connectors that link the No. 2 floor wire and front door wire LH.
      GTY896690Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Side Airbag Sensor Assembly LH
      *2 Rear Airbag Sensor LH
      *3 Front Door Wire LH
      *4 No. 2 Floor Wire
      *5 Service Wire
      *a Front view of wire harness connector
      (to Rear Airbag Sensor LH)
      *b Front view of wire harness connector
      (to Side Airbag Sensor Assembly LH)
    2. Connect the cable to the negative (-) auxiliary battery terminal.
    3. Turn the ignition switch to ON.
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      M62-1 (BDL+) - Body ground Ignition switch ON Below 1 V
      M62-2 (BDL-) - Body ground Ignition switch ON Below 1 V
    5. Turn the ignition switch off.
    6. Disconnect the cable from the negative (-) auxiliary battery terminal.
      WARNING:

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

    7. Using a service wire, connect terminals 2 (BDL+) and 1 (BDL-) of connector E.
      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
      M62-1 (BDL+) - M62-2 (BDL-) Always Below 1 Ω
    9. Disconnect the service wire from connector E.
    10. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      M62-1 (BDL+) - M62-2 (BDL-) Always 1 MΩ or higher
      M62-1 (BDL+) - Body ground Always 1 MΩ or higher
      M62-2 (BDL-) - Body ground Always 1 MΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  6

  6. CHECK REAR AIRBAG SENSOR LH 
    1. Connect the connectors to the side airbag sensor assembly LH and airbag sensor assembly.
      GTY447346Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Airbag Sensor RH
      *2 Airbag Sensor Assembly
    2. Interchange the rear airbag sensor LH with RH and connect the connectors.
    3. Connect the cable to the negative (-) auxiliary battery terminal.
    4. Turn the ignition switch to ON, and wait for at least 60 seconds.
    5. Clear the DTCs stored in memory.

      Body Electrical > SRS Airbag > Clear DTCs 

    6. Turn the ignition switch off.
    7. Turn the ignition switch to ON, and wait for at least 60 seconds.
    8. Check for DTCs.

      Body Electrical > SRS Airbag > Trouble Codes 

      HINT: 

      Codes other than DTCs B1633 and B1638 may be output at this time, but they are not related to this check.

      Result

      Result Proceed to
      DTC B1638 is output. A
      DTC B1633 is output. B
      DTCs B1633 and B1638 are not output. C
    9. Turn the ignition switch off.
    10. Disconnect the cable from the negative (-) auxiliary battery terminal.
      WARNING:

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

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

    Result: 

    A 

    REPLACE AIRBAG SENSOR ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

    Result: 

    B 

    REPLACE REAR AIRBAG SENSOR LH. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

    Result: 

    C 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ] 

  7. CHECK NO. 2 FLOOR WIRE 
    1. Disconnect the No. 2 floor wire connector from the front door wire LH.
      GTY847764Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Side Airbag Sensor Assembly LH
      *2 Rear Airbag Sensor LH
      *3 Front Door Wire LH
      *4 No. 2 Floor Wire
      *5 Service Wire
      *a Front view of wire harness connector
      (to Rear Airbag Sensor LH)
      *b Front view of wire harness connector
      (to Front Door Wire LH)
    2. Connect the cable to the negative (-) auxiliary battery terminal.
    3. Turn the ignition switch to ON.
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      JM3-1 (BDL+) - Body ground Ignition switch ON Below 1 V
      JM3-2 (BDL-) - Body ground Ignition switch ON Below 1 V
    5. Turn the ignition switch off.
    6. Disconnect the cable from the negative (-) auxiliary battery terminal.
      WARNING:

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

    7. Using a service wire, connect terminals 1 (BDL+) and 2 (BDL-) 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
      JM3-1 (BDL+) - JM3-2 (BDL-) 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
      JM3-1 (BDL+) - JM3-2 (BDL-) Always 1 MΩ or higher
      JM3-1 (BDL+) - Body ground Always 1 MΩ or higher
      JM3-2 (BDL-) - Body ground Always 1 MΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FRONT DOOR WIRE LH 

    Result: 

    NG 

    REPLACE NO. 2 FLOOR WIRE 

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