AIRBAG SYSTEM DIAGNOSIS SYSTEM


  1. DESCRIPTION


    1. The airbag ECU assembly controls the functions of the SRS of the vehicle. SRS data can be read using the vehicle's Data Link Connector 3 (DLC3). When the system seems to be malfunctioning, use the intelligent tester to check for malfunctions and perform repairs if necessary.

  2. DLC3 CHECK


    1. Check the DLC3 Click here.

  3. FUNCTION OF SRS WARNING LIGHT


    1. Primary check


      1. Turn the ignition switch off. Wait for at least 2 seconds, and then turn the ignition switch to ON again. The SRS warning light comes on for approximately 6 seconds and diagnosis of the SRS (including the seat belt pretensioner) is performed.

        Tech Tips

        If any malfunctions are detected, the SRS warning light remains on, even after the primary check has been completed.

    2. Constant check


      1. After the primary check, the airbag ECU assembly continues to monitor the SRS (including the seat belt pretensioner) for malfunctions.

        Tech Tips

        If any malfunctions are detected during the constant check, the airbag ECU assembly functions as follows:


        • The SRS warning light comes on.

        • There is the case that the SRS warning light goes off after the light was lit, however, this is caused by a temporary drop of the source voltage. When the source voltage has been recovered, the SRS warning light goes off automatically.

    3. Summary


      1. When the SRS is normal:

        The SRS warning light comes on only during the primary check period (for approximately 6 seconds after the ignition switch is turned from off to ON).

      2. When the SRS is malfunctioning:


        • The SRS warning light remains on, even after the primary check has been completed.

        • The SRS warning light goes off after the primary check, but comes on again during the constant check.

        • The SRS warning light does not come on, even though the ignition switch was turned from off to ON during the primary check.

        Tech Tips

        The airbag ECU assembly sends a signal to keep the SRS warning light on if malfunctions have been detected in the SRS. The SRS warning light is also kept on after the deployment of the SRS parts.

  4. SRS WARNING LIGHT CHECK

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    1. Turn the ignition switch to ON, and check that the SRS warning light comes on for approximately 6 seconds (primary check).

      Tech Tips

      If the following occurs, refer to the Problem Symptoms Table Click here.


      • The SRS warning light remains off, even when the ignition switch is turned from off to ON.

    2. Check that the SRS warning light goes off approximately 6 seconds after the ignition switch is turned to ON (constant check).

      Tech Tips

      If either of the following symptoms occurs, refer to the Problem Symptoms Table Click here.


      • The SRS warning light comes on occasionally, even after the primary check has been completed.

      • No DTCs are indicated, even when the SRS warning light is on.