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Check Key Warning Switch

  1. CHECK DATA MONITOR  .

    Using the Subaru Select Monitor, display the data of «key-lock warning SW».

    NOTE: For detailed operation procedures, refer to "Application help".

    Is the normal input signal displayed when the key is inserted in/removed from the ignition switch?

    Yes:  The key warning switch is OK.

    No:  Go to  2

  2. CHECK FUSE  .

    Remove and visually check fuse No. 14 (in the main fuse box).

    Is the fuse blown out?

    Yes:  Replace the fuse with a new part.

    No:  Go to  3

  3. CHECK KEY WARNING SWITCH CIRCUIT  .
    1. Disconnect the connector of body integrated unit.
    2. Insert the key into ignition switch. (LOCK position)
    3. Measure the voltage between the body integrated unit connector and chassis ground.

      Connector & terminal 

      (B280) No. 4 (+) - Chassis ground (-):

    Is the voltage 9 V or more?

    Yes:  Go to  4

    No:  Go to  5

  4. CHECK KEY WARNING SWITCH CIRCUIT  .
    1. Remove the key from ignition switch.
    2. Measure the voltage between the body integrated unit connector and chassis ground.

      Connector & terminal 

      (B280) No. 4 (+) - Chassis ground (-):

    Is the voltage less than 1.5 V?

    Yes:  The key warning switch is OK.

    No:  Go to  5

  5. CHECK KEY WARNING SWITCH  .
    1. Disconnect the connector of key warning switch.
    2. Insert the key into ignition switch. (LOCK position)
    3. Measure the resistance between key warning switch terminals.

      Terminals 

      No. 1 - No. 2:

    Is the resistance less than 1 Ω?

    Yes:  Go to  6

    No:  Replace the key warning switch.

  6. CHECK KEY WARNING SWITCH  .
    1. Remove the key from ignition switch.
    2. Measure the resistance between key warning switch terminals.

      Terminals 

      No. 1 - No. 2:

    Is the resistance 1 MΩ or more?

    Yes:  Check the following:

    • Harness for open circuits and shorts between the key warning switch and fuse.
    • Harness for open or short between the body integrated unit and key warning switch.

    No:  Replace the key warning switch.