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Home >> Lexus >> 2018 >> NX 300h >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Airbag System - Diagnostic Codes (3 Of 3) & Symptom Tests >> Airbag System >> SRS Warning Light Remains ON [10/2014 - 05/2019] >> Procedure

SRS Warning Light Remains ON [10/2014 - 05/2019]: Procedure

  1. CHECK CAN COMMUNICATION SYSTEM 
    1. Check if a CAN communication DTC is output.

      Refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2014 - 09/2017] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [09/2017 - 05/2019]

      Result

      Proceed to
      DTCs are output
      DTC is not output

    Result: 

    DTCs are output 

    GO TO CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2014 - 09/2017]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2017 - 05/2019] 

    Result: 

    DTC is not output 

    See step  2

  2. 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  3

  3. 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 90 seconds.
    3. Check that the connectors are properly connected to the airbag ECU assembly and combination meter assembly.

      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  4

  4. CHECK HARNESS AND CONNECTOR (AIRBAG ECU ASSEMBLY - BATTERY AND BODY GROUND) 
    1. Disconnect the connectors from the airbag ECU assembly.
      GTY500441Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Rear 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. Operate all the components of the electrical system (defogger, wipers, headlights, heater blower, etc.).
    5. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      I58-21 (IG2) - Body ground Power switch on (IG) 11 to 14 V
      I58-21 (IG2) - Body ground Power switch off Below 1 V
    6. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      I58-25 (E1) - Body ground Always Below 1 Ω
      I58-26 (E2) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE HARNESS AND CONNECTOR 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - BATTERY AND BODY GROUND) 
    1. Turn the power switch off.
    2. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 90 seconds.
      GTY499760Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Combination Meter Assembly)
    3. Disconnect the connector from the combination meter 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).
    6. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      I10-21 (IG+) - Body ground Power switch on (IG) 11 to 14 V
      I10-22 (B) - Body ground Power switch off 11 to 14 V
    7. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      I10-40 (EP) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. CHECK SRS WARNING LIGHT (SHORT TO GROUND) 
    1. Turn the power switch off.
    2. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 90 seconds.
    3. Connect the connector to the combination meter 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).
    6. Check the SRS warning light condition.

      OK

      After the primary check period, the SRS warning light goes off for approximately 10 seconds and then remains 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 [10/2014 - 05/2019] 

    Result: 

    NG 

    GO TO METER / GAUGE SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2014 - ] 

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