Battery Equivalents and Replacements

How to Change Subaru Key Fob Battery

For Subaru owners, the key fob is an integral part of the driving experience, offering convenience and security with the push of a button. From locking and unlocking your doors to starting your car, the key fob is a small but mighty component of your daily routine.

However, like all battery-operated devices, the key fob requires occasional maintenance, primarily in the form of battery replacement.

Published: February 23, 2024.

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Recognizing When to Replace Your Key Fob Battery

The most obvious sign that your Subaru key fob battery needs replacing is when the range or responsiveness decreases. If you find yourself pressing the button multiple times or getting closer to the vehicle for it to work, it's likely time for a new battery.

Additionally, some Subaru models will display a warning message on the dashboard indicating when the battery is low.

Choosing the Right Battery for Your Subaru Key Fob

Subaru key fobs generally use CR2025 or CR2032 lithium coin batteries. These batteries are readily available at electronics stores, supermarkets, and online.

It's crucial to use the correct type and size to ensure the best performance and to avoid damaging your key fob.

How to Replace Your Subaru Key Fob Battery

  • Open the Key Fob: Gently pry open the key fob using a flathead screwdriver or a dedicated key fob tool. Some models have a small notch designed for this purpose.
  • Identify the Battery Type: Once open, identify the battery type and note its orientation.
  • Replace the Battery: Remove the old battery, being careful not to touch the new battery's surface with your fingers, as oil and dirt can affect performance.
  • Place the new battery in the same orientation as the old one.
  • Close the Key Fob: Snap the key fob back together, ensuring it's securely closed.

Generally, a Subaru key fob does not require reprogramming after battery replacement. When you replace the battery in your Subaru key fob, the internal memory retains all the programming information, meaning it should continue to work with your vehicle without the need for reprogramming. This is standard for most automotive key fobs; the process of changing the battery doesn't affect the coding that allows the key fob to communicate with your car.

However, if you find that your key fob is not working correctly after replacing the battery, ensure the new battery is installed properly (with the correct orientation) and that it is fully functional (sometimes new batteries can be defective). It's also a good idea to make sure the battery compartment is clean and free from any dirt or corrosion that could affect the connection.

In the rare event that your key fob still doesn't work after checking these aspects, there may be other issues unrelated to the battery change, such as damage to the key fob itself or a problem with the vehicle's receiver system. In such cases, consulting with a Subaru dealer or a professional automotive locksmith who specializes in key fob programming may be necessary.

Popular Subaru Models and Their Key Fob Batteries

  • Subaru Forester: Years: 2009-2021, Key Fob Battery: CR2025 or CR2032, depending on the year and specific key fob design.
  • Subaru Outback: Years: 2010-2021, Key Fob Battery: CR2032 for most models.
  • Subaru Impreza: Years: 2008-2021, Key Fob Battery: CR2025 or CR2032, varying by model year and fob type.
  • Subaru Legacy: Years: 2005-2021, Key Fob Battery: CR2032 is commonly used, though some older models may use CR2025.
  • Subaru Crosstrek: Years: 2016-2021, Key Fob Battery: CR2032 for most key fob versions.
  • Subaru WRX/STI: Years: 2015-2021, Key Fob Battery: CR2032, although it's always best to check as specifications can vary.

First Signs of Weak Subaru Key Fob Battery

The first signs of a weak Subaru key fob battery are usually quite noticeable and can indicate that it's time to replace the battery. Here are some common symptoms to look out for:

  • Reduced Range: One of the earliest signs is a significant decrease in the range at which your key fob can effectively communicate with your Subaru. If you find yourself having to get closer to your vehicle than usual to unlock it or start the engine, this could indicate a weak battery.
  • Inconsistent Operation: If your key fob becomes unreliable, only working intermittently or requiring multiple presses to function, it's likely that the battery is losing its charge.
  • Delayed Response: A noticeable delay between pressing the key fob button and the vehicle's response (unlocking doors, trunk release, etc.) is another sign of a weak battery.
  • Dashboard Warning: Some Subaru models are equipped with a warning system that alerts the driver to a low key fob battery via the dashboard display. If you see such a warning, it's a clear indication that the battery needs replacing.
  • LED Indicator: If your key fob has an LED light that illuminates when a button is pressed and you notice that the light has dimmed or stopped lighting up altogether, this could be a sign that the battery is nearly depleted.
  • No Operation: The most obvious sign is when the key fob stops working entirely. While this could indicate other issues, a completely dead battery is the most common cause.

When you notice any of these signs, it's advisable to replace the key fob battery as soon as possible to maintain the functionality and convenience of your Subaru's keyless entry and ignition system.

Doing so can prevent you from being locked out of your vehicle or unable to start it due to a dead key fob battery.

How to Start Subaru With Dead Key Fob Battery?

Starting a Subaru when the key fob battery is dead can still be accomplished through a backup procedure designed for such situations. While the exact method may vary slightly depending on the model and year of your Subaru, the following steps generally apply to most recent Subaru vehicles equipped with a push-button start system:

For Subaru Models with Push-Button Start:

  • Remove the Mechanical Key: First, remove the mechanical key hidden inside the key fob. There's usually a small release button on the back of the fob that allows you to slide out the key.
  • Unlock the Door Manually: Use the mechanical key to unlock the driver's door. While newer Subaru models rely heavily on electronic systems, they still feature a physical lock for emergencies.
  • Hold the Key Fob to the Start Button: Once inside, press the brake pedal (for automatic transmissions) or the clutch pedal (for manual transmissions) to prepare for starting. Then, take the key fob and press it against the push-button start. Most Subaru vehicles have a built-in NFC (Near Field Communication) reader in the start button that can detect the key fob even if the fob's battery is dead. In some models, you might find a designated backup area to place the key fob, often indicated in the owner's manual.
  • Press the Start Button: While holding the key fob against the button, press it to start the engine. The car's system should recognize the key fob even without a working battery through this direct contact method.

Subaru Models with Keyed Ignition:

For Subaru models with a traditional keyed ignition, the key fob often has a built-in physical key that can be used directly in the ignition switch. Here’s how you can start such models if the key fob battery is dead:

  • Remove the Mechanical Key: Similar to the push-button start models, the key fob usually includes a mechanical key that can be removed by pressing a small release button or lever on the fob.
  • Unlock the Door: Use the mechanical key to manually unlock the driver’s door. This is necessary since the remote unlocking feature will not work with a dead key fob battery.
  • Start the Car: Insert the mechanical key into the ignition switch and turn it to start the car just as you would under normal circumstances. The presence of a dead key fob battery does not affect the ability of the mechanical key to start the car in models with a traditional ignition system.

Note for Models with a Transponder Chip:

It's worth noting that even Subaru models with a traditional keyed ignition may have a transponder chip embedded in the key for security purposes.

This chip communicates with the car's immobilizer system to allow the engine to start. In these cases, the physical key contains the necessary chip and does not rely on battery power from the key fob to start the car.

Therefore, a dead key fob battery should not prevent the car from starting as long as you use the mechanical key.

Additional Tips:

  • Refer to Your Owner's Manual: Specific instructions for starting your Subaru with a dead key fob battery may vary depending on the model and year. Consult your vehicle's owner's manual for detailed instructions tailored to your specific Subaru.
  • Replace the Key Fob Battery: After starting your vehicle, consider replacing the key fob battery as soon as possible to restore its normal functionality. Subaru key fobs typically use CR2032 or CR2025 lithium coin batteries, which are readily available and easy to replace.

This method ensures that even if the key fob battery is completely dead, you won't be stranded and can still start your Subaru.

It's a smart practice to familiarize yourself with this procedure and where the mechanical key is located within your key fob before you find yourself in an emergency situation.

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Few Final Words

Maintaining your Subaru key fob by regularly checking and replacing the battery as needed will ensure you can always rely on it for easy access to your vehicle. By following this guide, Subaru owners can feel confident in managing one of the most critical components of their vehicle's convenience features.

Always dispose of old batteries properly by recycling them or taking them to a facility that can handle them responsibly.