Check Key Warning Switch

Display the [Key-lock Warning SW] data using Subaru Select Monitor.

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

1. Yes: The key warning switch is OK.
2. No: Go to 2  .

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

Is the fuse blown out?

1. Yes: Replace the fuse with a new part.
2. No: Go to 3  .

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?

1. Yes: Go to 4  .
2. No: Go to  5.

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?

1. Yes: The key warning switch is OK.
2. No: Go to 5  .

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?

1. Yes: Go to 6  .
2. No: Replace the 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?

1. 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.
2. No: Replace the key warning switch.