Check Key Switch Circuit

CAUTION: When the body integrated unit is replaced, registration of the immobilizer system is required. For details, refer to the "REGISTRATION MANUAL FOR IMMOBILIZER" provided as a separate volume.

Wiring diagram:

Immobilizer system Ref. to WIRING SYSTEM>IMMOBILIZER SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

CHECK POWER SUPPLY CIRCUIT.
1. Disconnect the connector from key warning switch.
2. Measure the voltage between key warning switch connector terminal and chassis ground.
  Connector & terminal
  
  (B555) No. 1 (+) - Chassis ground (-):
Is the voltage 10 V or more?

Yes: Go to 2.

No: Check the harness for an open or short between the key warning switch and fuse.
CHECK KEY WARNING SWITCH.
1. Insert the ignition key in the ignition switch. (OFF or ACC)
2. Measure the resistance between key warning switch connector terminals.
  Terminals
  
  No. 1 - No. 2:
Is the resistance less than 1 Ω?

Yes: Go to 3.

No: Replace the key warning switch. Ref. to SECURITY AND LOCKS>KEY LOCK CYLINDERS .
CHECK KEY WARNING SWITCH.
1. Remove the ignition key from ignition switch.
2. Measure the resistance between key warning switch connector terminals.
  Terminals
  
  No. 1 - No. 2:
Is the resistance 1 MΩ or more?

Yes: Go to 4.

No: Replace the key warning switch. Ref. to SECURITY AND LOCKS>KEY LOCK CYLINDERS .
CHECK HARNESS BETWEEN KEY WARNING SWITCH AND BODY INTEGRATED UNIT (OPEN).
1. Disconnect the connector from body integrated unit.
2. Measure the resistance between key warning switch connector terminal and body integrated unit connector terminal.
  Connector & terminal
  
  (B555) No. 2 - (B280) No. 4:
Is the resistance less than 10 Ω?

Yes: Replace the body integrated unit. Ref. to SECURITY AND LOCKS>BODY INTEGRATED UNIT .

No: Repair the harness between key warning switch and body integrated unit.