AIRBAG SYSTEM SRS Warning Light Remains ON

DESCRIPTION

The SRS warning light is located in the combination meter assembly.

When the SRS is normal, the SRS warning light comes on for approximately 6 seconds after the engine switch is turned from off to on (IG), and then goes off automatically.

If there is a malfunction in the SRS, the SRS warning light comes on to inform the driver of a problem.

If a malfunction occurs in the airbag ECU assembly, combination meter assembly or wire harness connected to the airbag ECU assembly or combination meter assembly, the SRS warning light turns on.

When terminals TC and CG of the DLC3 are connected, DTCs are displayed by blinking of the SRS warning light.

The SRS is equipped with a voltage-increase circuit (DC-DC converter) in the airbag ECU assembly in case the source voltage drops.

When the battery voltage drops, the voltage-increase circuit (DC-DC converter) functions to increase the voltage of the SRS to normal voltage. In addition, when the voltage drops, the SRS warning light will illuminate.

A malfunction in this circuit is not stored in the airbag ECU assembly. The SRS warning light automatically goes off when the source voltage returns to normal.

The signal to illuminate the SRS warning light is transmitted from the airbag ECU assembly to the combination meter assembly via the CAN communication system.

WIRING DIAGRAM

B002D2GE01

CAUTION / NOTICE / HINT

Note


  • After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

    Click here

  • Inspect the fuses for circuits related to this system before performing the following procedure.

  • When disconnecting the cable from the negative (-) battery terminal while performing repairs, some systems need to be initialized after the cable is reconnected.

    Click here

  • After replacing the airbag ECU assembly, refer to initialization.

    Click here

PROCEDURE


  1. CHECK SRS WARNING LIGHT OPERATION


    1. Turn the engine switch on (IG) and check the SRS warning light condition.

      Tech Tips

      The primary check is performed for approximately 6 seconds after the engine switch is turned on (IG).

      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 turns off and turns on again. B

    B

    CHECK CAN COMMUNICATION SYSTEM Click here

    A

  2. CHECK BATTERY VOLTAGE


    1. Measure the voltage of the battery.

      Standard Voltage
      11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    INSPECT CHARGING SYSTEM AND BATTERY Click here

    OK

  3. CHECK CONNECTOR


    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 connector is properly connected to the airbag ECU assembly.

      OK
      The connector is properly connected.

      Tech Tips

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

    4. Disconnect the connector from the airbag ECU assembly.

    5. Check that the terminals of the connector are not damaged.

      OK
      The terminals are not deformed or damaged.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE WIRE HARNESS

    OK

  4. CHECK WIRE HARNESS (AIRBAG ECU ASSEMBLY - BODY GROUND)


    1. B002DDAC39
      *a

      Front view of wire harness connector

      (to Airbag ECU Assembly)

      Connect the cable to the negative (-) battery terminal.

    2. Turn the engine switch on (IG).

    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
      K43-21 (IG2) - Body ground Engine switch on (IG) 8 to 16 V

    5. Turn the engine switch off.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K43-25 (E1) - Body ground Always Below 1 Ω
      K43-26 (E2) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE WIRE HARNESS

    OK

  5. CHECK SRS WARNING LIGHT


    1. Turn the engine switch on (IG) and check the SRS warning light condition.

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

      Tech Tips

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

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE AIRBAG ECU ASSEMBLY Click here

    NG

    REPLACE COMBINATION METER ASSEMBLY Click here

  6. CHECK CAN COMMUNICATION SYSTEM


    1. Using the GTS, check if the CAN communication system is functioning normally.

      OK
      CAN communication system is functioning normally.

      Tech Tips


      • Refer to CAN Bus Check for the CAN communication system.

        for LHD: Click here

        for RHD: Click here

      • The airbag ECU assembly is connected to the CAN communication system. Therefore, before starting troubleshooting, make sure to check that there are no malfunctions in the CAN communication system.

      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    B

    GO TO CAN COMMUNICATION SYSTEM Click here

    C

    GO TO CAN COMMUNICATION SYSTEM Click here

    A

  7. CHECK BATTERY VOLTAGE


    1. Measure the voltage of the battery.

      Standard Voltage
      11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    INSPECT CHARGING SYSTEM AND BATTERY Click here

    OK

  8. CHECK CONNECTOR


    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 connector is properly connected to the airbag ECU assembly.

      OK
      The connector is properly connected.

      Tech Tips

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

    4. Disconnect the connector from the airbag ECU assembly.

    5. Check that the terminals of the connector are not damaged.

      OK
      The terminals are not deformed or damaged.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE WIRE HARNESS

    OK

  9. CHECK WIRE HARNESS (AIRBAG ECU ASSEMBLY - BODY GROUND)


    1. B002DDAC39
      *a

      Front view of wire harness connector

      (to Airbag ECU Assembly)

      Connect the cable to the negative (-) battery terminal.

    2. Turn the engine switch on (IG).

    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
      K43-21 (IG2) - Body ground Engine switch on (IG) 8 to 16 V

    5. Turn the engine switch off.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K43-25 (E1) - Body ground Always Below 1 Ω
      K43-26 (E2) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE WIRE HARNESS

    OK

  10. CHECK CONNECTOR


    1. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

    2. Check that the connector is properly connected to the combination meter assembly.

      OK
      The connector is properly connected.

      Tech Tips

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

    3. Disconnect the connector from the combination meter assembly.

    4. Check that the terminals of the connector are not damaged.

      OK
      The terminals are not deformed or damaged.
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE CONNECTOR

    OK

  11. CHECK WIRE HARNESS (COMBINATION METER ASSEMBLY - BODY GROUND)


    1. B002DPYC32
      *a

      Front view of wire harness connector

      (to Combination Meter Assembly)

      Connect the cable to the negative (-) battery terminal.

    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
      K33-21 (IG+) - Body ground Engine switch on (IG) 11 to 14 V
      K33-22 (B) - Body ground Always 11 to 14 V

    4. Turn the engine switch off.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K33-31 (ES) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE WIRE HARNESS

    OK

  12. CHECK SRS WARNING LIGHT


    1. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

    2. Connect the connector to the combination meter assembly.

    3. Connect the cable to the negative (-) battery terminal.

    4. Turn the engine switch on (IG) and check the SRS warning light condition.

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

      Tech Tips

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

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE AIRBAG ECU ASSEMBLY Click here

    NG

    REPLACE COMBINATION METER ASSEMBLY Click here