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Home >> Toyota >> 2021 >> Mirai XLE >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Airbag System - Diagnostic Codes (8 Of 8) & Symptom Tests (1 Of 2) >> Airbag System >> SRS Warning Light Remains ON [11/2021 - 12/2022] >> Procedure

SRS Warning Light Remains ON [11/2021 - 12/2022]: Procedure

  1. CHECK SRS WARNING LIGHT OPERATION 
    1. Turn the ignition switch to ON and check the SRS warning light condition.

      HINT: 

      The primary check is performed for approximately 6 seconds after the ignition switch is turned to ON.

      Result

      Result Proceed to
      After the primary check period, the SRS warning light remains on. A
      After the primary check period, the SRS warning light goes off and comes on again. B

    Result: 

    B 

    See step  7

    Result: 

    A 

    See step  2

  2. CHECK AUXILIARY BATTERY 
    1. Measure the auxiliary battery voltage with the ignition 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 CONNECTOR 
    1. Turn the ignition switch off.
    2. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 90 seconds.
    3. Check that the connector is properly connected to the airbag ECU assembly.

      OK

      The connectors are properly connected.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CONNECT CONNECTORS PROPERLY 

    Result: 

    OK 

    See step  4

  4. CHECK CONNECTOR 
    1. Disconnect the airbag ECU assembly connector.
      GTY973791Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Combination Meter
      *2 Airbag ECU Assembly
      *3 Wire Harness
    2. Check that the connectors (on the airbag ECU assembly side) are not damaged.

      OK

      The connectors are not deformed or damaged.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (AIRBAG ECU 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 ignition switch to ON.
    3. Operate all components of the electrical systems (defogger, wipers, headlights, heater blower, etc.).
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      D10-36 (IG2) - Body ground Ignition switch ON 8 to 16 V
    5. Turn the ignition switch off.
    6. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      D10-33 (E1) - Body ground Always Below 1 Ω
      D10-32 (E2) - 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 ignition switch to ON.
      GTY973703Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Combination Meter Assembly
      *2 Airbag ECU Assembly
      *3 Wire Harness
    2. Approximately 6 seconds after the ignition switch to ON, check the condition of the SRS warning light.

      Result

      Result  Proceed to
      Turns off for 10 seconds, and then illuminates A
      Turns off for 10 seconds, and then remains off B

    Result: 

    A 

    REPLACE AIRBAG ECU ASSEMBLY. Refer to  REMOVAL [11/2021 - 12/2022] 

    Result: 

    B 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [11/2021 - 12/2022] 

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

      Refer to DIAGNOSIS SYSTEM [11/2020 - 12/2022]

      Result

      Result  Proceed to
      DTCs are output A
      DTC is not output B

    Result: 

    A 

    GO TO CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - 12/2022] 

    Result: 

    B 

    See step  8

  8. CHECK AUXILIARY BATTERY 
    1. Measure the auxiliary battery voltage with the ignition 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  9

  9. CHECK CONNECTOR 
    1. Turn the ignition 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 and airbag ECU assembly.

      OK

      The connectors are properly connected.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CONNECT CONNECTORS PROPERLY 

    Result: 

    OK 

    See step  10

  10. CHECK CONNECTOR 
    1. Disconnect the airbag ECU assembly connector.
      GTY973647Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Combination Meter Assembly
      *2 Airbag ECU Assembly
      *3 Wire Harness
    2. Disconnect the combination meter assembly connector.
    3. Check that the connectors (on the combination meter side and airbag ECU assembly side) are not damaged.

      OK

      The connectors are not deformed or damaged.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS AND CONNECTOR 

    Result: 

    OK 

    See step  11

  11. CHECK HARNESS AND CONNECTOR (AIRBAG ECU ASSEMBLY - AUXILIARY BATTERY AND BODY GROUND) 
    1. Connect the cable to the negative (-) auxiliary battery terminal.
    2. Turn the ignition switch to ON.
    3. Operate all components of the electrical systems (defogger, wipers, headlights, heater blower, etc.).
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      D10-36 (IG2) - Body ground Ignition switch ON 8 to 16 V
    5. Turn the ignition switch off.
    6. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      D10-33 (E1) - Body ground Always Below 1 Ω
      D10-32 (E2) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS AND CONNECTOR 

    Result: 

    OK 

    See step  12

  12. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - BATTERY AND BODY GROUND) 
    1. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      w/o Advanced Park 

      Tester Connection Switch Condition Specified Condition
      D41-21 (IG+) - Body ground Ignition switch ON 11 to 14 V

      w/ Advanced Park 

      Tester Connection Switch Condition Specified Condition
      D44-6 (IG+) - Body ground Ignition switch ON 11 to 14 V
    2. Turn the ignition switch off.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      w/o Advanced Park 

      Tester Connection Condition Specified Condition
      D41-31 (ES) - Body ground Always Below 1 Ω

      w/ Advanced Park 

      Tester Connection Switch Condition Specified Condition
      D44-2 (ES) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  13

  13. CHECK SRS WARNING LIGHT 
    1. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 60 seconds.
      GTY973703Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Combination Meter Assembly
      *2 Airbag ECU Assembly
      *3 Wire Harness
    2. Connect the D41*1 or D44*2 combination meter assembly connector.
      1. *1: w/o Advanced Park
      2. *2: w/ Advanced Park
    3. Connect the cable to the negative (-) auxiliary battery terminal.
    4. Approximately 6 seconds after the ignition switch to ON, check the condition of the SRS warning light.

      Result

      Result  Proceed to
      Turns off for 10 seconds, and then illuminates A
      Turns off for 10 seconds, and then remains off B

    Result: 

    A 

    REPLACE AIRBAG ECU ASSEMBLY. Refer to  REMOVAL [11/2021 - 12/2022] 

    Result: 

    B 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [11/2021 - 12/2022] 

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