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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 (3 Of 3) >> AIRBAG SYSTEM (w/o Advanced Park) >> SRS Warning Light does not Come ON [10/2020 - 10/2023] >> Procedure

SRS Warning Light does not Come ON [10/2020 - 10/2023]: Procedure

  1. CHECK AUXILIARY BATTERY 
    1. Measure the auxiliary battery voltage with the power switch off.

      Standard voltage

      11 to 14 V

      HINT: 

      It may be possible to tell whether the auxiliary battery is discharged by operating the horn.

      If the voltage is below 11 V, recharge or replace the auxiliary battery before proceeding to the next step.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE OR RECHARGE AUXILIARY BATTERY 

    Result: 

    OK 

    See step  2

  2. CHECK CONNECTOR 
    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 connector is properly connected to the combination meter assembly.

      OK

      The connector is properly connected.

      HINT: 

      If the connector is not properly connected, reconnect the connector and proceed to the next inspection.

    4. Disconnect the connector from the combination meter assembly.
    5. Check that the terminals of the connector are not deformed or damaged.

      OK

      The terminals are not deformed or damaged.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE CONNECTOR 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - AUXILIARY BATTERY AND BODY GROUND) 
    1. Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
    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
      G34-21 (IG+) - Body ground Power switch on (IG) 11 to 14 V
      G34-22 (B) - Body ground Power switch off 11 to 14 V
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G34-31 (ES) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. CHECK SRS WARNING LIGHT 
    1. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 60 seconds.
    2. Connect the connector to the combination meter assembly.
    3. Disconnect the connector from the pedestrian detection ECU assembly.
    4. Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
    5. Turn the power switch on (IG) and check the SRS warning light condition.

      OK

      After the primary check period, the SRS warning light turns off for approximately 10 seconds and then turns back on.

      HINT: 

      The primary check period is approximately 6 seconds after the power switch is turned on (IG).

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    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: 

    NG 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2023]