What is the security light on my Subaru dashboard?

The security light on a Subaru dashboard is the immobilizer/anti-theft indicator. It shows whether the vehicle recognizes your key and whether the anti-theft system is active. In normal operation, the light behaves briefly and then goes out, and it should not block your engine from starting.

What the security light means

This section explains the common patterns you might see and what they typically indicate about the immobilizer or anti-theft system in most Subaru models with a transponder key.

• The light comes on briefly when you turn the ignition to ON, then it goes out. This is normal and means the system is checking for a recognized key.


• The light flashes or blinks during starting or when you press the keyless entry button. This usually indicates the anti-theft system is arming/disarming or verifying the key, which can be normal if you’re locking/unlocking the car.


• The light stays on after you start the engine. This suggests a fault with the immobilizer or key recognition and typically requires diagnostic service to identify the issue.


• The light blinks rapidly or stays on while attempting to start. This signals the key is not being recognized (transponder issue or weak key battery) and you should try a spare key or replace the key fob battery.


• The light stays on or continues to blink while driving. This is unusual and may indicate a more serious immobilizer or alarm system fault; professional inspection is recommended.

In summary, the security light is a diagnostic indicator for the immobilizer/anti-theft system. Normal behavior is a brief flash when you power up, followed by a steady state off; deviations from that pattern warrant further checks.

What you can do yourself

Before seeking service, you can perform a few basic checks to rule out simple causes of immobilizer trouble.

• Check the key fob battery and try a spare key. A weak battery or a damaged key can prevent the immobilizer from recognizing the key.


• Ensure you’re using the correct key for the vehicle. If you have multiple keys, one may be faulty or unprogrammed for this car.


• If your Subaru has a push-button start, try starting with the fob held near the start button or in the designated slot if your model supports it; some models have a physical backup key inside the fob.


• Inspect for after-market alarms or immobilizers that could be interfering. If you recently installed an aftermarket system, it could trigger the security light.


• Make sure there aren’t any obvious electrical issues, such as a loose connection or blown fuse related to the ignition or immobilizer circuits. If in doubt, don’t force-start the car repeatedly.

If these steps don’t restore normal behavior, it’s time to seek professional help to diagnose the immobilizer system and transponder communication with the PCM.

Model-specific notes

Subaru models vary in how the security/immobilizer indicator is displayed and how the system behaves, especially between traditional ignition and push-button start with Intelligent Key systems. Refer to your owner's manual for the exact icon (often a key or lock symbol) and the expected light pattern for your year and model.

Push-button start vs. traditional ignition

Most newer Subarus use a push-button start with the Intelligent Key. If the key battery is dead or if the key isn’t detected, the immobilizer may prevent starting and illuminate the security light. In older models with a traditional ignition, the light behavior is similar, but the ignition mechanics differ, so consult the manual for your specific configuration.

When to seek professional help

Contact a Subaru dealer or qualified automotive locksmith if you observe persistent immobilizer issues, such as:

• The security light stays on after multiple restarts and the engine won’t start.


• The light blinks rapidly or cycles during starting and this pattern repeats across attempts.


• You’ve tried a spare key and replaced the key fob battery with no improvement.


• You suspect an aftermarket alarm or wiring modification is affecting the immobilizer system.

A professional diagnosis can determine whether the issue lies with the key transponder, immobilizer control unit, wiring, or a related component, and can include reprogramming keys if necessary.

Summary

The Subaru security light is an immobilizer/anti-theft indicator. Normal operation involves a brief activation when you power up, followed by the light going out. If the light stays on, blinks, or behaves unusually, it points to key recognition or immobilizer problems that typically require diagnostic service. Start with simple checks like the key fob battery and spare key, then consult a dealer or locksmith if issues persist. For model-specific guidance, always refer to your owner's manual.

What does security indicator light mean on a Subaru?

A blinking security light on a Subaru means the anti-theft immobilizer system is armed and the vehicle is locked. This is a normal security feature that prevents the engine from starting without a properly coded key and serves as a deterrent to thieves. If the light is steady or flashing rapidly, it could indicate a problem with the security system or key fob battery, and you should check the fob or consult your owner's manual.
 
Normal operation

• Blinking: The light blinks slowly when the key is out of the ignition or after the engine has been turned off and the doors are locked. This indicates the immobilizer system is active. 
• Deterrent: The blinking light acts as a passive anti-theft measure, visible through the windows to discourage potential thieves. 

Potential problems

• Steady light: A steady light may signal a problem with the anti-theft system, such as an unprogrammed or damaged key, or an issue with a sensor. 
• Rapid flashing: A rapid flashing light could mean the alarm system has been triggered or that there's an issue with the immobilizer system not functioning properly. 
• Car won't start: If the light flashes rapidly while you are trying to start the car, it usually means the key fob is not being detected. This could be due to a dead battery in the fob or a problem with the car's security system. 
• Access key issues: For cars with a push-button start, a flashing indicator when trying to start the engine can mean the access key is not in the vehicle or has a weak battery. 

What to do

• If the light is blinking normally: You don't need to do anything. This is just the car's security system at work. 
• If the car won't start and the light is flashing: Check the battery in your key fob and replace it if needed. If you have a spare key, try using that. 
• If the light is steady or flashing rapidly and the car won't start: The issue may be more complex. Check your owner's manual for troubleshooting steps, or contact a Subaru dealer or a qualified automotive locksmith for assistance. 

How do I turn off the security light on my Subaru?

To turn off a Subaru's security indicator light, first ensure the car is in a normal state by closing all doors. If the light is blinking, start the car; it should turn off automatically. If it's a flashing red light that means the anti-theft system is active, try locking and unlocking the doors with the key fob to reset it. If the light is a steady red and the car won't start, the system may be indicating a more serious problem, such as a key fob issue, and you may need to try a spare key or contact a dealer for service. 
This video demonstrates how to disable the alarm system on a Subaru Outback: 56sSubaruOwnerTipsYouTube · Nov 3, 2019
If the light is blinking

• The blinking is normal: A blinking light when the car is off is usually the security system's immobilizer, which is normal. The light should turn off once you start the car with a valid key. 
• Reset the system: If you're trying to start the car and the light is blinking and the car won't start, try locking and unlocking the doors with the key fob to reset the system. 
• Try a different key: The problem could be with the key itself. Try using a spare key to see if that resolves the issue. 
• Check the key fob battery: A dead key fob battery can prevent the car from recognizing the key. Replace the battery in the fob and try again. 

If the light is steady and the car won't start

• A steady light could indicate a problem with the key fob or the vehicle's security system. 
• You may need to try using a spare key. 
• It might be necessary to take the car to a dealer to have the system diagnosed and reprogrammed. 

This video explains why the security light might be flashing and how to turn it off: 57sNexologyYouTube · Aug 11, 2025
Other troubleshooting steps

• Check for simple issues: Ensure all doors, including the trunk and hood, are fully closed, as a faulty door sensor can trigger a false alarm. 
• Disconnect the battery: You can try disconnecting the car's battery for about 10 minutes to reset the system, which can sometimes help the system recognize the key again. 
• Check the owner's manual: Your Subaru's owner's manual will have specific instructions for your model. 

What causes the security indicator light to come on?

A lit security indicator light means your car's anti-theft system is active, which could be a normal function or signal a problem with the key or immobilizer system. To fix it, first try using a spare key, or resetting the system by turning the ignition on for a few minutes and then starting the car. If the light remains on, there may be a more significant issue, such as a faulty key, a dead car battery, or a problem with the security system itself, and you should consult a mechanic. 
This video explains what to do if your car's security light is on: 1mJerry aiYouTube · Nov 1, 2022
What to do if the security light is on

• Try a spare key: This is the easiest first step and can quickly resolve issues caused by a faulty transponder chip in your primary key. 
• Reset the system: 
  • Turn the ignition to the "on" position without starting the engine. 
  • Keep it in this position for about 10 minutes, or until the light stops flashing. 
  • Turn the car off, then try starting it normally. 
• Check the battery: A weak car battery can sometimes trigger the anti-theft system, so try charging or replacing it if it's old. 
• Consult your owner's manual: Your car's manual will have specific instructions for troubleshooting and resetting the security system for your make and model. 
• Seek professional help: If these steps don't work, take your car to a mechanic or dealership. The problem could be a faulty key, a damaged ignition switch, or a more complex issue with the anti-theft system that requires reprogramming or repair. 

What is the most serious Subaru warning light?

What is the most serious warning light? Of all Subaru dashboard symbols and meanings, the Oil Pressure Warning Light, Brake System Warning Light, and Battery Warning Light are possible causes for concern. Still, the Check Engine Warning Light is one of the most urgent symbols.