Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Key Interlock Cannot Be Locked Or Released
- CHECK BODY INTEGRATED UNIT POWER SUPPLY AND GROUND CIRCUIT
.
Is there any fault?
Yes: Follow the procedures to inspect and repair.
No: 2
- CHECK CURRENT DATA
.
- Connect the Subaru Select Monitor.
- Shift the select lever to "P" range.
- Turn the ignition switch to ON.
- Select the current data display and display «P SW». Ref. to BODY CONTROL SYSTEM (DIAGNOSTICS)>Read Current Data
Is the display "ON" in the P range and "OFF" in ranges other than P?
Yes: 3
No: 6
- CHECK CURRENT DATA
.
- Select the current data display and display the «key-lock warning SW». Ref. to BODY CONTROL SYSTEM (DIAGNOSTICS)>Read Current Data
- Turn the ignition switch to OFF.
Does the display change from "ON" ←→ "OFF" when the key is inserted and removed?
Yes: 4
No: 9
- CHECK CURRENT DATA
.
- Turn the ignition switch to ON.
- Select the current data display and display «Key lock solenoid output». Ref. to BODY CONTROL SYSTEM (DIAGNOSTICS)>Read Current Data
Is the display "OFF" in the P range and "ON" in ranges other than P?
Yes: 10
No: 5
- CHECK DTC OF BODY INTEGRATED UNIT
.
- Set the select lever to other than "P" range.
- Check DTC of body integrated unit.
Is B1015 (key interlock circuit abnormal) a current malfunction?
Yes: Follow the DTC to perform inspection and repair.
No: 10
- CHECK HARNESS BETWEEN BODY INTEGRATED UNIT AND "P" RANGE SWITCH
.
- Disconnect the connector from body integrated unit.
- Disconnect the connector of "P" range switch.
- Check for open circuit of harness, short circuit to battery or short circuit to ground between the body integrated unit and "P" range switch.
Connector & Terminal
(B281) No. 18 - (B116) No. 1:
Is there any fault in the harness?
Yes: Repair or replace the harness between the body integrated unit and the "P" range switch.
No: 7
- CHECK HARNESS BETWEEN "P" RANGE SWITCH AND CHASSIS GROUND
.
Measure the resistance of harness between "P" range switch and chassis ground.
Connector & Terminal
(B116) No. 2 - Chassis ground:
Is it less than 10 Ω?
Yes: 8
No: Repair or replace the harness between the "P" range switch and chassis ground.
- CHECK "P" RANGE SWITCH
.
Measure the resistance between "P" range switch connector terminals.
Terminals
No. 2 - No. 1:
Is it less than 10 Ω in the "P" range, and 1 MΩ or more in ranges other than "P"?
Yes: Replace the body integrated unit.
No: Replace the "P" Range Switch.
- CHECK HARNESS BETWEEN BATTERY AND KEY WARNING SWITCH AND BODY INTEGRATED UNIT
.
- Disconnect the connector from body integrated unit.
- Measure the voltage between body integrated unit and chassis ground.
Connector & Terminal
(B280) No. 4 (+) - Chassis ground (-):
Is the display 9 V or more when the key is inserted, and less than 1.5 V with the key removed?
Yes: Replace the body integrated unit.
No: Check the following items.
- Key warning switch
- Harness/fuse
- Ignition circuit
- CHECK HARNESS BETWEEN BODY INTEGRATED UNIT AND KEY LOCK SOLENOID
.
- Disconnect the connector from body integrated unit.
- Disconnect the connector of key lock solenoid.
- Check for open circuit of harness, short circuit to battery or short circuit to ground between the body integrated unit and key lock solenoid.
Connector & Terminal
(B281) No. 4 - (B557) No. 1:
Is there any fault in the harness?
Yes: Repair or replace the harness between the body integrated unit and the key lock solenoid.
No: 11
- CHECK HARNESS BETWEEN KEY LOCK SOLENOID AND CHASSIS GROUND
.
Measure the resistance of harness between key lock solenoid and chassis ground.
Connector & Terminal
(B557) No. 2 - Chassis ground:
Is it less than 10 Ω?
Yes: 12
No: Repair or replace the harness between the key lock solenoid and chassis ground.
- CHECK KEY LOCK SOLENOID OPERATION
.
Connect the battery to the key lock solenoid connector terminal, and operate the solenoid.
Terminals
No. 2 (+) - No. 1 (-):
Does the key lock solenoid operate normally?
Yes: 13
No: Replace the key lock solenoid.
- CHECK OUTPUT OF BODY INTEGRATED UNIT
.
- Connect all connectors.
- Insert the key.
- Measure the voltage between body integrated unit and chassis ground.
Connector & Terminal
(B281) No. 4 - Chassis ground:
Is it 7.5 V to 16 V in ranges other than "P", and approx. 0 V in the "P" range?
Yes: Check the lock mechanism of the steering lock body.
No: Replace the body integrated unit.
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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