DTC B1015: Key Interlock Circuit

DTC detecting condition: 

Short to ground in key interlock circuit

Trouble symptom: 

Key interlock does not keep lock condition.

Wiring diagram: 

Shift lock control system Ref. to WIRING SYSTEM>Shift Lock Control System>WIRING DIAGRAM

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC  .
   1. Insert the ignition key.
   2. Turn the ignition switch to ON.
   3. Shift to the Neutral range.
   4. Shift into P range.
   5. Shift to the Neutral range.
   6. Shift into P range.
   7. Shift to the Neutral range.
   8. Read the DTC of body integrated unit using Subaru Select Monitor. Ref. to BODY CONTROL SYSTEM (DIAGNOSTICS)>Read Diagnostic Trouble Code (DTC) 

   Is DTC B1015 displayed? (Current malfunction)

   Yes: Go to  2

   No: Go to  8

2. CHECK DTC  .
   1. Shift the select lever to P range.
   2. Remove the ignition key.
   3. Disconnect the key actuator connector (B557) and body integrated unit connector (B281).
   4. Connect the disconnected connectors.
   5. Insert the ignition key.
   6. Turn the ignition switch to ON and shift into Neutral.
   7. Read the DTC of body integrated unit using Subaru Select Monitor. Ref. to BODY CONTROL SYSTEM (DIAGNOSTICS)>Read Diagnostic Trouble Code (DTC) 

   Is DTC B1015 displayed? (Current malfunction)

   Yes: Go to  3

   No: Go to  8

3. CHECK KEY ACTUATOR  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the key actuator connector (B557).
   3. Measure the resistance between key actuator connectors.

      Terminals

      Key actuator

      No. 1 - No. 2:

   Is the resistance 103 - 115 Ω?

   Yes: Go to  4

   No: Replace the key actuator. Ref. to SECURITY AND LOCKS>Key Lock Cylinders

4. CHECK KEY ACTUATOR  .

   Connect the battery terminals to the key actuator.

   Terminals

   Key actuator

   No. 1 - Positive terminal:

   No. 2 - Ground terminal:

   Is the actuator activated and then key locked?

   Yes: Go to  5

   No: Replace the key actuator. Ref. to SECURITY AND LOCKS>Key Lock Cylinders

5. CHECK HARNESS  .
   1. Disconnect the body integrated unit connector (B281).
   2. Measure the resistance between body integrated unit and key actuator using tester.

      Connector & terminal 

      (B557) No. 1 - (B281) No. 4:

   Is the resistance less than 10 Ω?

   Yes: Go to  6

   No: Repair or replace the open circuit of harness.

6. CHECK HARNESS (GROUND SHORT CIRCUIT)  .

   Measure the resistance between body integrated unit and chassis ground using tester.

   Connector & terminal 

   (B281) No. 4 - Chassis ground:

   Is the resistance 1 MΩ or more?

   Yes: Go to  7

   No: Repair or replace the short circuit of the harness.

7. CHECK HARNESS  .
   1. Connect the body integrated unit.
   2. Turn the ignition switch to ON.
   3. Measure the voltage between body integrated unit and chassis ground using tester.

      Connector & terminal 

      (B281) No. 4 (+) - Chassis ground (-):

   Is the voltage 6 V or more?

   Yes: Go to  8

   No: Replace the body integrated unit. Ref. to SECURITY AND LOCKS>Body Integrated Unit

8. CHECK CONNECTOR  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the body integrated unit connector (B281) and key actuator connector (B557).

   Is there poor contact at disconnected connector terminal?

   Yes: Repair the terminal where poor contact exists, or replace harness.

   No: Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

   NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.