Why wont my Subaru key lock my car?
The quick answer is that the problem is usually a weak or dead key fob battery, a low or dead car battery, or a faulty lock actuator or receiver. Start by changing the key fob battery and trying the mechanical key to determine whether the issue is with the remote or the car’s locking system.
Understanding how Subaru remote locking works
Subaru vehicles equipped with remote entry use a wireless key fob to communicate with the car’s locking system. The system depends on a healthy battery in the key fob, sufficient power in the car’s electrical system, and a responsive door lock actuator. Any single weak link—battery, receiver, actuator, or immobilizer—can prevent the doors from locking when you press the lock button on the fob.
Common causes for a remote that won’t lock
Below are the most frequent culprits behind a remote lock that isn’t functioning correctly.
- Dead or weak key fob battery (often the first and easiest fix).
- Key fob is mispaired or needs to be reprogrammed to the vehicle.
- Vehicle battery is low or discharged, reducing power to the locking system.
- Faulty door lock actuator or damaged wiring in the lock circuit.
- Immobilizer/anti-theft system not recognizing the key, which can affect lock function on some models.
- Radio interference or signal-blocking conditions temporarily preventing the fob’s signal from reaching the car.
- A mechanical issue with the door lock cylinder or linkage that prevents locking even when the fob works.
If the problem persists after checking these common causes, a diagnostic with a Subaru dealer or qualified shop is recommended to pinpoint a fault in the receiver, actuator, or immobilizer.
What to do next: a practical troubleshooting checklist
The following steps progress from quick DIY checks to professional help if needed. Use them in order to identify the likely culprit.
- Check and replace the key fob battery. Use the correct type (commonly CR2032) and ensure the battery is seated properly. After replacement, test both lock and unlock functions.
- Try the spare key fob. If the spare works but the primary does not, the original fob is likely failing or out of sync and may need reprogramming or replacement.
- Test the car with the mechanical key. If your Subaru has a mechanical key blade hidden in the fob or a visible keyhole, use it to lock/unlock the driver’s door to determine whether the issue is with the fob or the door lock mechanism.
- Check the car battery and electrical system. A severely discharged battery can prevent the locking system from drawing power. If the voltage is low, charge or replace the battery and re-test.
- Inspect fuses related to the door locks. Look for a fuse labeled Power Door Lock or similar in the vehicle’s fuse box and replace if blown.
- Consider immobilizer/anti-theft issues. If the dash immobilizer light behaves oddly or the engine won’t start after pressing the fob, the key may need reprogramming or the immobilizer module may require service.
- Re-pair or reprogram the key fob if your model requires it. Some Subarus require dealer tools or specialized procedures to re-sync a replacement or re-paired fob with the vehicle’s computer.
- If none of the above steps resolves the issue, schedule service with a Subaru dealer or a certified automotive locksmith for a thorough diagnosis and potential replacement of the fob, receiver, or related components.
Note: For models with push-button start and Intelligent Key systems, re-pairing procedures or fob replacement may be necessary after battery work or if a fob is replaced. Always consult your owner's manual or a dealer for model-specific instructions.
Key fob battery replacement
Most Subaru fob batteries last several years, but performance can drop quickly if the key is frequently used or exposed to extreme temperatures. Replace with the correct battery type, re-test the fob, and dispose of the old battery properly.
Testing the mechanical key
If your Subaru has a hidden or visible mechanical key slot, use the physical key to verify that the door locks operate mechanically. If mechanical locking works but the remote does not, the problem is with the fob or its communication with the car rather than the lock mechanism itself.
When to seek professional help
If the issue persists after all basic checks, a dealership or certified locksmith can reprogram the fob, diagnose a faulty receiver or BCM (body control module), and inspect the door lock actuators and wiring for faults.
Model-specific notes
Some Subaru models have varying procedures for keyless entry and immobilizer systems. Always check the owner’s manual for your exact model year and trim to learn the correct battery type, fob reprogramming steps, and any model-specific quirks that could affect locking from the remote.
Summary
Most lock failures on Subarus come from a weak key fob battery, a tired car battery, a faulty door lock actuator, or immobilizer-related issues. Begin with simple tests—change the key fob battery, try the spare, and use the mechanical key if available—and progress to fuse checks and reprogramming if needed. If problems persist, a dealer or qualified locksmith can diagnose and repair more complex issues with the receiver, BCM, or immobilizer to restore reliable locking.
