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Home >> Lexus >> 2021 >> LC 500 2D Coupe >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Airbag System - Diagnostic Codes (Coupe) (3 Of 5) >> Airbag System >> DTC B1660: P Seat Airbag Active Mode Indicator [05/2023 - ] >> Procedure

DTC B1660: P Seat Airbag Active Mode Indicator [05/2023 - ]: Procedure

  1. CHECK PASSENGER AIRBAG ON/OFF INDICATOR CONDITION 
    1. Turn the engine switch on (IG).
    2. Check the passenger airbag ON/OFF indicator operation.

      HINT: 

      Refer to the normal condition of the passenger airbag ON/OFF indicator.

      Refer to HOW TO PROCEED WITH TROUBLESHOOTING [05/2023 - ]

      Result

      Result Proceed to
      ON/OFF indicator illumination is always on. A
      ON/OFF indicator illumination is always off. B

    Result: 

    B 

    See step  7

    Result: 

    A 

    See step  2

  2. CHECK CONNECTION OF CONNECTORS 
    1. Turn the engine switch off.
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    3. Check that the connectors are properly connected to the airbag ECU assembly and multi-display.

      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  3

  3. CHECK CONNECTORS 
    1. Disconnect the connectors from the airbag ECU assembly and multi-display.
      GTY747083Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Multi-display
      *2 Airbag ECU Assembly
      *3 Instrument Panel Wire
    2. Check that the connectors (on the airbag ECU assembly side and multi-display 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 

    Result: 

    The connectors are not deformed or damaged 

    See step  4

  4. CHECK PASSENGER AIRBAG ON/OFF INDICATOR 
    1. Connect the connector to the multi-display.
    2. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
    3. Turn the engine switch on (IG).
    4. Check the passenger airbag ON/OFF indicator operation.

      Result

      Proceed to
      The passenger airbag ON/OFF indicator does not come on
      The passenger airbag ON/OFF indicator comes on

    Result: 

    The passenger airbag ON/OFF indicator comes on 

    See step  6

    Result: 

    The passenger airbag ON/OFF indicator does not come on 

    See step  5

  5. CHECK DTC 
    1. Turn the engine switch off.
      GTY752413Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Multi-display
      *2 Airbag ECU Assembly
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    3. Connect the connectors to the airbag ECU assembly.
    4. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
    5. Turn the engine switch on (IG), and wait for at least 60 seconds.
    6. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [04/2020 - ]

      Body Electrical > SRS Airbag > Clear DTCs 

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

      Refer to DTC CHECK / CLEAR [04/2020 - ]

      Body Electrical > SRS Airbag > Trouble Codes 

      Result

      Proceed to
      DTC B1660 is not output
      DTC B1660 is output

      HINT: 

      Codes other than DTC B1660 may be output at this time, but they are not related to this check.

    Result: 

    DTC B1660 is not output 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [05/2023 - ] 

    Result: 

    DTC B1660 is output 

    REPLACE AIRBAG ECU ASSEMBLY. Refer to  REMOVAL [05/2023 - ] 

  6. CHECK PASSENGER AIRBAG ON/OFF INDICATOR CIRCUIT 
    1. Turn the engine switch off.
      GTY1242437Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Multi-display
      *2 Airbag ECU Assembly
      *3 Instrument Panel Wire
      *4 Service Wire
      *a Front view of wire harness connector
      (to Multi-display)
      *b Front view of wire harness connector
      (to Airbag ECU Assembly)
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    3. Disconnect the connector from the multi-display.
    4. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
    5. Turn the engine switch on (IG).
    6. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      P145-6 (P-AB) - Body ground Engine switch on (IG) Below 1 V
      P145-5 (PAON) - Body ground Engine switch on (IG) Below 1 V
    7. Turn the engine switch off.
    8. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    9. Using a service wire, connect terminals 35 (PAON) and 34 (P-AB) of connector B.
      NOTE:

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

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      P145-6 (P-AB) - P145-5 (PAON) Always Below 1 Ω
    11. Disconnect the service wire from connector B.
    12. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P145-6 (P-AB) - P145-5 (PAON) Always 1 MΩ or higher
      P145-6 (P-AB) - Body ground Always 1 MΩ or higher
      P145-5 (PAON) - Body ground Always 1 MΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MULTI-DISPLAY. Refer to  REMOVAL [05/2023 - ] 

    Result: 

    NG 

    REPLACE INSTRUMENT PANEL WIRE 

  7. CHECK CONNECTION OF CONNECTORS 
    1. Turn the engine switch off.
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    3. Check that the connectors are properly connected to the airbag ECU assembly and multi-display.

      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  8

  8. CHECK CONNECTORS 
    1. Disconnect the connectors from the airbag ECU assembly and multi-display.
      GTY747083Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Multi-display
      *2 Airbag ECU Assembly
      *3 Instrument Panel Wire
    2. Check that the connectors (on the airbag ECU assembly side and multi-display 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 

    Result: 

    The connectors are not deformed or damaged 

    See step  9

  9. CHECK PASSENGER AIRBAG ON/OFF INDICATOR CIRCUIT 
    1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
      GTY1242437Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Multi-display
      *2 Airbag ECU Assembly
      *3 Instrument Panel Wire
      *4 Service Wire
      *a Front view of wire harness connector
      (to Multi-display)
      *b Front view of wire harness connector
      (to Airbag ECU Assembly)
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      P145-6 (P-AB) - Body ground Engine switch on (IG) Below 1 V
      P145-5 (PAON) - Body ground Engine switch on (IG) Below 1 V
    4. Turn the engine switch off.
    5. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    6. Using a service wire, connect terminals 35 (PAON) and 34 (P-AB) 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
      P145-6 (P-AB) - P145-5 (PAON) 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
      P145-6 (P-AB) - P145-5 (PAON) Always 1 MΩ or higher
      P145-6 (P-AB) - Body ground Always 1 MΩ or higher
      P145-5 (PAON) - Body ground Always 1 MΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE INSTRUMENT PANEL WIRE 

    Result: 

    OK 

    See step  10

  10. CHECK PASSENGER AIRBAG ON/OFF INDICATOR (SOURCE VOLTAGE) 
    1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
      GTY1242369Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Multi-display)
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      P145-1 (IG+) - Body ground Engine switch on (IG) 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  11

  11. CHECK PASSENGER AIRBAG ON/OFF INDICATOR 
    1. Turn the engine switch off.
      GTY825476Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Airbag ECU Assembly)
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    3. Connect the connector to the multi-display.
    4. Using a service wire, connect terminal 35 (PAON) and body ground.
    5. Using a service wire, connect terminal 34 (P-AB) and body ground.
    6. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
    7. Turn the engine switch on (IG).
    8. Check the indicator according to the table below.

      OK

      Tester Connection Switch Condition Passenger Airbag ON/OFF Indicator
      P6-35 (PAON) - Body ground Engine switch on (IG) "ON" comes on
      P6-34 (P-AB) - Body ground Engine switch on (IG) "OFF" comes on
    9. Turn the engine switch off.
    10. Disconnect the service wire from airbag ECU assembly.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE MULTI-DISPLAY. Refer to  REMOVAL [05/2023 - ] 

    Result: 

    OK 

    See step  12

  12. CHECK DTC 
    1. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
      GTY752413Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Multi-display
      *2 Airbag ECU Assembly
    2. Connect the connectors to the airbag ECU assembly.
    3. Connect the cable to the negative (-) battery terminal and wait for at least 2 seconds.
    4. Turn the engine switch on (IG), and wait for at least 60 seconds.
    5. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [04/2020 - ]

      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.

      Refer to DTC CHECK / CLEAR [04/2020 - ]

      Body Electrical > SRS Airbag > Trouble Codes 

      Result

      Proceed to
      DTC B1660 is not output
      DTC B1660 is output

      HINT: 

      Codes other than DTC B1660 may be output at this time, but they are not related to this check.

    Result: 

    DTC B1660 is not output 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [05/2023 - ] 

    Result: 

    DTC B1660 is output 

    REPLACE AIRBAG ECU ASSEMBLY. Refer to  REMOVAL [05/2023 - ] 

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