Subaru Forester Key Fob Battery Replacement: Complete Guide

Replacing a Subaru Forester key fob battery is a simple maintenance task that most of us can complete at home without visiting a dealership. Whether the remote has stopped unlocking the doors, its operating range has decreased, or the dashboard displays a low key battery warning, installing a fresh battery may restore normal functionality.

The good news is that we generally need only a replacement coin-cell battery and a small flathead screwdriver. The process typically takes just a few minutes, provided we know how to open the remote safely.

However, there is one important detail: not every Subaru Forester key fob uses the same battery. Depending on the model year and key design, we may need a CR2032, CR1632, or CR1620 lithium battery.

In this comprehensive guide, we'll explain how to identify the correct battery, replace it safely, troubleshoot common problems, and keep our Subaru Forester key fob working reliably.

What Battery Does a Subaru Forester Key Fob Use?

The battery required for a Subaru Forester key fob depends primarily on its generation and whether it uses a conventional remote-head key or a smart key with push-button start.

The CR2032 is commonly used in newer Subaru Forester smart keys, while certain older remotes require a CR1632 or CR1620.

These are general guidelines rather than universal specifications. Battery requirements can vary by market, equipment, and remote design.

Before purchasing a replacement, we recommend checking the marking on the existing battery or consulting the vehicle's owner's manual.

CR2032 vs CR1632 vs CR1620 Batteries

Although these batteries look similar, their dimensions are different.

All three use lithium chemistry and provide a nominal voltage of 3 volts.

However, we should never assume they are interchangeable.

Installing an incorrectly sized battery could damage the battery contacts or prevent the remote casing from closing properly.

Signs Your Subaru Forester Key Fob Battery Is Dying

A weak key fob battery rarely causes every function to fail immediately. In many cases, we'll notice gradual changes in how the remote operates.

Recognising these warning signs can help us replace the battery before it becomes completely discharged.

Reduced Remote Control Range

One of the earliest symptoms is a noticeable reduction in operating distance.

For example, we might previously have been able to unlock our Subaru Forester from several metres away, but now the remote only works when standing close to the driver's door.

Although radio interference can affect range, a weak battery is a common explanation.

Subaru Forester Key Battery Low Warning

Certain Forester models with smart key systems can display a warning indicating that the remote battery is running low.

This notification means we should consider replacing the battery soon.

Ignoring it may eventually result in difficulties unlocking the vehicle or using the keyless start system.

Buttons Not Responding Consistently

Another symptom is having to press the lock or unlock button repeatedly before the vehicle responds.

Occasional failures can also be caused by damaged buttons or electrical interference, but replacing an ageing battery is a practical first troubleshooting step.

Key Not Detected Message

If the vehicle occasionally displays a key detection warning, the smart key battery may no longer provide reliable operation.

We may notice that the vehicle recognises the remote only when it is positioned close to the ignition button.

However, similar symptoms can occur because of interference, a faulty key, or vehicle electrical problems.

Intermittent Keyless Entry

Some Forester owners notice that the door handle sensors stop responding consistently while the remote buttons continue working.

A weak smart key battery can contribute to this problem.

Before assuming that the door handle sensors are defective, we should check the battery condition.

Tools Needed for Subaru Forester Key Fob Battery Replacement

We don't need specialised automotive equipment to replace most Subaru Forester key fob batteries.

The following items are usually sufficient:

• A compatible CR2032, CR1632, or CR1620 battery.
• A small flathead screwdriver.
• A soft cloth or insulating tape.
• A clean, dry work surface.
• A plastic opening tool, if available.

The cloth or tape protects the plastic housing from scratches when using a screwdriver.

It's also helpful to work over a table rather than opening the remote while standing outside, where small components could fall and become lost.

Safety note: Coin-cell batteries are dangerous if swallowed. Keep them away from children and pets, and seek immediate emergency medical assistance if ingestion is suspected.

How to Replace a Subaru Forester Smart Key Battery

The procedure below applies to many Subaru Forester smart access keys equipped with an emergency mechanical key.

While the exact casing design can vary, the general process is similar.

Step 1: Remove the Mechanical Emergency Key

Start by holding the Subaru Forester key fob securely.

Find the small release button or switch on the back or side of the remote.

Press or slide the release mechanism while pulling out the mechanical key.

This metal key is designed to provide access to the vehicle if the remote battery becomes discharged.

Set it aside temporarily.

Step 2: Open the Key Fob Casing

Once we've removed the mechanical key, inspect the remote for an opening slot or seam.

Wrap the tip of a small flathead screwdriver in a thin cloth or insulating tape.

Carefully insert the screwdriver into the designated opening point.

Apply gentle pressure to separate the two halves of the housing.

We should avoid twisting the screwdriver aggressively because the internal plastic clips can break.

If the casing doesn't open easily, stop and verify the correct procedure for the specific key design.

Step 3: Locate the Existing Battery

After separating the casing, we'll find a small circular battery inside the remote.

Before removing it, observe the positive and negative markings.

For many Subaru Forester smart keys using a CR2032 battery, the positive side faces upward.

However, this arrangement should be confirmed for the particular remote.

Taking a quick photograph of the battery position before removal can help us avoid mistakes during installation.

Step 4: Remove the Old Battery

Carefully lift the old battery from its compartment.

We can use a small non-metallic tool or another suitable implement that won't damage the electrical contacts.

Avoid applying force directly to the circuit board.

The battery should come free without excessive pressure.

If the metal retaining contacts appear bent or corroded, the remote may require additional inspection.

Step 5: Insert the Replacement Battery

Take the new battery out of its packaging.

Confirm that its specification matches the old battery.

Insert it into the compartment, maintaining the correct polarity.

For the common CR2032 smart key arrangement, the positive (+) side is positioned upward.

Make sure the battery:

• Fits securely inside the holder.
• Makes proper contact with the terminals.
• Is installed in the correct orientation.
• Has no protective packaging remaining.
• Does not require excessive force to insert.

If the battery doesn't fit naturally, double-check its dimensions.

Step 6: Reassemble the Remote

Align the two sections of the key fob casing.

Press them together carefully until the retaining clips snap into place.

Check the edges to ensure there are no visible gaps.

Reinsert the emergency mechanical key and confirm that it locks into position.

The remote should now look exactly as it did before opening.

Step 7: Test the Subaru Forester Key Fob

Stand close to the vehicle and press the unlock button.

If the doors unlock normally, test the lock button as well.

For vehicles equipped with keyless access, we should also verify that the door handle sensors and push-button start system recognise the remote.

If everything operates correctly, the battery replacement is complete.

How to Replace the Battery in an Older Subaru Forester Key

Some older Subaru Forester models have a traditional ignition key with an integrated remote transmitter.

This type of key may require a slightly different battery replacement procedure.

Many conventional Subaru transmitters use a CR1620 battery.

Opening a Traditional Subaru Key

First, locate the seam or designated opening point in the plastic key head.

Use a small screwdriver to open the housing carefully.

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Depending on the design, we may need to remove a separate internal transmitter module.

Once the module is accessible, open its battery compartment following the correct procedure.

Replacing the CR1620 Battery

Remove the existing battery and check its markings.

Install a new battery with the correct polarity.

Importantly, certain Subaru conventional transmitters require the negative side to face upward, which differs from many smart key designs.

We should follow the exact instructions for our transmitter rather than copying the orientation from another Subaru key.

Reassembling and Testing the Key

Close the transmitter module and reinstall it inside the key housing.

Make sure the housing clips are properly secured.

Test the locking and unlocking functions.

Some older Subaru transmitters may require a synchronisation procedure after battery replacement. If the remote doesn't respond, consult the vehicle-specific instructions before assuming that the key is defective.

Subaru Forester Key Fob Battery Replacement by Year

Subaru has used different remote designs across Forester generations.

Understanding these differences can make the replacement process easier.

Subaru Forester 2014 Key Fob Battery Replacement

The 2014 Subaru Forester was available with different key configurations depending on equipment and market.

Certain smart access keys use a CR1632 battery, while conventional remote transmitters may use a CR1620.

Because these batteries have different dimensions, checking the original battery is especially important.

Subaru Forester 2015 Key Fob Battery Replacement

The 2015 Forester uses similar remote configurations to the preceding model year.

Some smart keys require a CR1632 battery.

Traditional remote-head keys can use a CR1620.

The replacement process generally involves opening the housing, removing the old battery, installing a compatible replacement, and checking remote operation.

Subaru Forester 2016 Key Fob Battery Replacement

Many 2016 Forester smart access keys use a CR2032 battery.

However, conventional transmitters can have different requirements.

Before starting, identify which type of remote came with the vehicle.

Opening the correct compartment carefully is essential to avoiding damage.

Subaru Forester 2017 Key Fob Battery Replacement

For many 2017 Forester smart keys, a CR2032 battery is appropriate.

The process normally involves removing the mechanical key, separating the casing, and replacing the battery.

No specialised programming is usually required for a routine smart key battery replacement.

Subaru Forester 2018 Key Fob Battery Replacement

The 2018 Forester uses a comparable approach for smart key battery maintenance.

A CR2032 is commonly specified for the smart access key.

Once the replacement battery is installed correctly, the remote should resume normal operation.

Subaru Forester 2019–2021 Key Fob Battery Replacement

The fifth-generation Subaru Forester introduced updated styling, technology, and safety systems.

For the smart access key, the CR2032 remains a common battery specification.

Changing the battery generally doesn't erase the key's electronic registration.

After replacement, we should test both remote entry and push-button ignition.

Subaru Forester 2022–2024 Key Fob Battery Replacement

Many Forester smart keys from these years also use a CR2032 battery.

The basic replacement steps remain familiar:

1. Remove the emergency key.
2. Open the remote housing.
3. Remove the discharged battery.
4. Install the correct replacement.
5. Close the housing.
6. Test the remote.

Always confirm the specification for the exact remote design.

Subaru Forester 2025 Key Fob Battery Replacement

The redesigned 2025 Forester introduced several updates, but its remote still uses a replaceable battery.

Because battery specifications and procedures can vary by market and key configuration, it's best to confirm the requirements in the owner's manual.

Avoid assuming that every previous-generation remote uses identical components.

Subaru Forester 2026 Key Fob Battery Replacement

For a 2026 Subaru Forester, check the model-specific manual or the battery marking inside the remote.

The basic replacement procedure is similar to earlier smart keys, although the housing design and required battery should be verified.

How Long Does a Subaru Forester Key Fob Battery Last?

A Subaru Forester key fob battery commonly lasts approximately one to three years, depending on usage patterns and environmental conditions.

Some batteries may last longer, while others can discharge more quickly.

Frequency of Remote Use

Frequent locking and unlocking contributes to battery consumption.

Drivers who use their vehicles several times daily may replace their key fob batteries more often than occasional drivers.

Keyless Access Technology

Smart key systems operate differently from traditional remote transmitters.

Their battery life depends on how the electronic system communicates with the vehicle and the environment in which the key is used.

Environmental Conditions

Extreme temperatures may affect battery performance.

For example, exposure to very cold conditions can temporarily reduce battery output.

Excessive heat and moisture can also damage key fob components.

Battery Quality

A genuine, correctly specified battery from a reputable manufacturer is generally a reliable choice.

We should avoid old batteries with damaged packaging or uncertain storage histories.

Subaru Forester Key Fob Battery Replacement Cost

One of the main advantages of replacing the battery ourselves is the low cost.

A suitable lithium coin-cell battery typically costs only a few dollars.

Professional replacement services may charge additional labour fees.

If the remote is working normally apart from a weak battery, DIY replacement is usually the most economical option.

However, professional assistance may be worthwhile if the housing is damaged or the internal battery contacts require repair.

Subaru Forester Key Fob Not Working After Battery Replacement

Occasionally, the remote may fail to operate even after we've installed a fresh battery.

Several issues could explain this situation.

Incorrect Battery Orientation

Installing the battery backwards can prevent the remote from functioning.

Open the casing again and compare the battery position with the recommended orientation.

This is especially important because not all Subaru remotes use the same polarity arrangement.

Wrong Battery Type

A battery that looks similar may have different dimensions.

For example, a CR1620 and CR1632 share the same diameter but have different thicknesses.

Using the wrong size can prevent the terminals from making proper contact.

Poor Electrical Contact

If the retaining contacts are dirty, bent, or damaged, the remote may not receive reliable power.

We should inspect them carefully without applying excessive force.

Damaged Remote Buttons

Sometimes the battery isn't the problem.

Repeated use can wear out the buttons or internal electrical contacts.

If only one button fails while the others work correctly, button-related damage may be responsible.

Faulty Circuit Board

Moisture exposure, physical damage, or accidental force during disassembly can affect the remote electronics.

A completely unresponsive key with a properly installed, known-good battery may require professional inspection.

Remote Synchronisation Problems

Certain older Subaru remote transmitters have model-specific synchronisation procedures.

Most modern smart keys don't require programming after a simple battery change.

However, if an older remote stops communicating with the vehicle, checking its synchronisation instructions is worthwhile.

Vehicle Electrical Problems

If both available key fobs stop working at the same time, we should investigate the vehicle itself.

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A discharged 12-volt battery, receiver fault, or other electrical issue may explain the symptoms.

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Working through these checks can help us identify the actual problem before purchasing an expensive replacement remote.

Can You Start a Subaru Forester With a Dead Key Fob Battery?

Yes. Many Subaru Forester models equipped with push-button start include an emergency procedure for recognising a registered smart key whose battery is discharged.

The exact sequence can vary by model year.

Emergency Start Procedure

For compatible Forester models, the general process is:

1. Enter the vehicle using the emergency mechanical key if necessary.
2. Close the driver's door.
3. Make sure the transmission is in Park.
4. Apply the brake pedal.
5. Hold the registered key fob against the engine start/stop button as directed by the owner's manual.
6. Wait for the vehicle to recognise the key.
7. Press the ignition button according to the vehicle's instructions.

This procedure allows certain Subaru smart key systems to authenticate the registered key despite its weak or discharged coin-cell battery.

However, it doesn't solve problems involving a completely discharged vehicle battery or an unregistered key.

How to Unlock the Subaru Forester With a Dead Key Fob

Most smart key fobs include a removable emergency mechanical key.

Press the release mechanism and remove the metal key.

Insert it into the driver's door lock cylinder and unlock the vehicle manually.

This provides an alternative way to access the vehicle when the remote's electronic functions are unavailable.

Does a Subaru Forester Key Need Reprogramming After Battery Replacement?

In most modern Subaru Forester smart key systems, replacing the coin-cell battery doesn't require reprogramming.

The key's registration information remains stored in its electronics.

Therefore, changing the battery should not erase the key's identity.

However, we should distinguish three different procedures.

Battery Replacement

This involves removing the discharged coin cell and installing a new one.

It normally doesn't change the electronic registration.

Remote Synchronisation

Certain older transmitters may require a specific process to restore normal remote operation after battery replacement.

The exact procedure depends on the vehicle and key design.

New Key Programming

Programming is required when a new electronic key must be registered to the vehicle.

This is a different process from routine battery maintenance.

Best Batteries for Subaru Forester Key Fobs

When selecting a new battery, reliability and compatibility should be our main priorities.

Several established manufacturers produce lithium coin-cell batteries suitable for automotive remotes.

Common brands include Panasonic, Energizer, Duracell, Sony, and Maxell.

Regardless of the brand, we should make sure the battery:

• Matches the required specification.
• Has a nominal voltage of 3 volts.
• Comes from a reputable retailer.
• Has been stored properly.
• Is not expired or damaged.

Buying a multipack can be convenient, but we should store spare batteries safely and avoid keeping loose coin cells near metal objects.

How to Make Your Subaru Forester Key Fob Battery Last Longer

Although key fob batteries eventually require replacement, a few simple habits may help maintain reliable performance.

Keep the Key Away From Extreme Temperatures

Avoid leaving the remote exposed to prolonged direct sunlight or excessive heat.

Extremely cold conditions can also affect temporary battery performance.

Prevent Unnecessary Button Presses

When a key fob is stored tightly against other objects, buttons may be pressed accidentally.

A protective case or suitable storage location can help reduce this problem.

Protect the Remote From Moisture

Subaru key fobs contain sensitive electronic components.

Avoid exposing them to rain, water immersion, or excessive humidity.

If water enters the remote, professional inspection may be necessary.

Check the Spare Key Regularly

A spare key can be extremely useful when the main remote fails.

However, its battery may also become depleted over time.

Testing the spare occasionally helps ensure it remains functional.

Replace the Battery Before Complete Failure

If the remote starts behaving inconsistently, replacing the battery early is usually preferable to waiting for complete failure.

This is especially helpful before long journeys.

Common Mistakes During Subaru Forester Key Fob Battery Replacement

A simple maintenance procedure can become expensive if we damage the remote.

The following mistakes are worth avoiding.

Forcing the Key Fob Open

Excessive pressure can break the plastic retaining clips.

Use a suitable opening tool and apply gentle force only at the designated points.

Installing an Incorrect Battery

Even when two batteries have the same voltage, their physical dimensions may differ.

Always match the required specification.

Ignoring Battery Polarity

An incorrectly positioned battery may prevent the remote from functioning.

Check the positive and negative markings before closing the casing.

Damaging the Internal Contacts

Metal contacts inside the key fob are delicate.

Avoid bending them while removing the old battery.

Touching the Circuit Board Excessively

Unnecessary contact with the electronics increases the risk of contamination or damage.

Handle the remote carefully and work in a clean, dry environment.

Failing to Close the Housing Properly

A partially open casing may allow moisture and dirt to enter.

Make sure every retaining clip is securely engaged.

Subaru Forester Key Fob Battery vs Car Battery

The key fob battery and the vehicle's main 12-volt battery serve different purposes.

The coin-cell battery powers the remote's electronics, while the vehicle battery supplies power to the car's electrical systems.

Understanding this distinction helps prevent unnecessary repairs.

For example, if the vehicle has no electrical power, installing a new key fob battery won't restore the main battery.

When Should You Replace the Entire Subaru Forester Key Fob?

Replacing the battery is usually the first step when remote functions become unreliable.

However, some situations may require replacing the entire key.

Possible reasons include:

• Severe physical damage to the casing.
• A broken or corroded circuit board.
• Water damage affecting internal electronics.
• Buttons that no longer operate.
• Broken battery contacts that cannot be repaired economically.
• Failure to communicate with the vehicle despite appropriate troubleshooting.

A replacement smart key generally requires registration or programming to work with the vehicle.

Because this can be more expensive than battery replacement, we should confirm that the existing remote is genuinely defective before purchasing a new one.

Is It Better to Replace the Key Fob Battery Yourself or Visit a Dealership?

For most Subaru Forester owners, DIY battery replacement is a practical option.

The procedure is generally quick, inexpensive, and requires minimal equipment.

However, visiting a professional may be appropriate when the remote casing is difficult to open, the internal electronics are damaged, or the key continues malfunctioning after battery replacement.

If we're comfortable handling small electronic components and following the vehicle's instructions, replacing the battery ourselves is usually the most convenient choice.

Frequently Asked Questions About Subaru Forester Key Fob Battery Replacement

1. What Battery Does a Subaru Forester Key Fob Take?

Many newer Subaru Forester smart keys use a CR2032 3-volt lithium battery. Some older models require a CR1632 or CR1620, depending on the key design. Always verify the battery type using the existing battery or owner's manual.

2. How Do I Change the Battery in My Subaru Forester Key Fob?

Remove the emergency mechanical key, carefully open the remote casing, take out the old battery, and install a compatible replacement with the correct polarity. Close the housing securely and test the lock, unlock, and smart key functions.

3. How Long Does a Subaru Forester Key Fob Battery Last?

A Subaru Forester key fob battery commonly lasts around one to three years. Battery lifespan varies with usage frequency, environmental conditions, key design, and battery quality.

4. Will Replacing the Battery Reset My Subaru Forester Key Fob?

Most modern Subaru Forester smart keys don't lose their programming when the battery is replaced. Certain older conventional remotes may require a model-specific synchronisation procedure.

5. Why Is My Subaru Forester Key Fob Not Working After Changing the Battery?

Possible explanations include an incorrectly installed battery, the wrong battery specification, poor electrical contact, damaged buttons, radio interference, or a fault in the remote electronics. Checking battery orientation and ensuring the replacement is correct are sensible first steps.

Final Thoughts: Subaru Forester Key Fob Battery Replacement

Replacing a Subaru Forester key fob battery is one of the simplest ways to maintain reliable access to our vehicle.

For many newer Forester smart keys, the replacement battery is a CR2032, while older key designs may require a CR1632 or CR1620. Identifying the correct specification is essential before beginning.

With a compatible battery, a suitable opening tool, and a little care, we can normally complete the replacement at home without professional assistance.

It's important to follow the correct battery orientation, avoid damaging the internal contacts, and check that the casing is securely closed.

If the remote continues malfunctioning after replacement, troubleshooting the electrical contacts, remote electronics, and vehicle systems can help identify the underlying issue.

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By recognising the early signs of a weak battery and replacing it promptly, we can avoid unnecessary inconvenience and keep our Subaru Forester key fob functioning reliably throughout everyday use.