We’ve all been there. You walk up to your Peugeot 308, press the unlock button with confidence… and nothing happens. No flash. No click. No response. Just silence.

A Peugeot 308 key fob not working isn’t just inconvenient—it can throw off your entire day. But here’s the good news: in most cases, it’s something simple. A battery. A re-sync. A minor glitch. Rarely is it catastrophic.

In this in-depth guide, we’ll walk through every possible cause, every proven fix, and every prevention tip—so you can get back behind the wheel without stress.

Understanding How the Peugeot 308 Key Fob Works

Before we fix it, let’s understand it.

Your key fob communicates with the car using a radio frequency signal. When you press a button:

1. The battery powers a microchip.
2. The chip sends an encrypted signal.
3. The car’s receiver validates the signal.
4. The doors unlock (or lock).

If any of those steps fail, the fob appears “dead.”

Common Symptoms When the Key Fob Stops Working

Not all failures look the same. You might experience:

• No response at all
• Intermittent unlocking
• Car starts but remote won’t unlock doors
• Warning: “Key not detected”
• Reduced operating range

Each symptom points to a different root cause.

Most Common Cause: Dead Key Fob Battery

Let’s start with the obvious.

How Long Does a Peugeot 308 Key Battery Last?

Typically:

• 2 to 4 years
• Depending on usage frequency
• Shorter lifespan in cold climates

Most Peugeot 308 key fobs use a CR2032 coin battery.

Signs the Battery Is Dying

• You must stand very close to unlock
• Buttons work inconsistently
• Dashboard shows key warning

It’s like a flashlight fading before going dark.

How to Replace the Peugeot 308 Key Fob Battery

This is a 5-minute job.

What You’ll Need

• CR2032 battery
• Small flat screwdriver
• Clean surface

Step-by-Step Process

1. Slide out the emergency key.
2. Insert screwdriver into side notch.
3. Gently twist to open casing.
4. Remove old battery.
5. Insert new battery (positive side up).
6. Snap casing closed.

That’s it.

No programming required in most cases.

Key Fob Still Not Working After Battery Change?

Now things get interesting.

If replacing the battery doesn’t fix it, we move to deeper diagnostics.

Key Fob Needs Re-Synchronization

Sometimes the fob loses communication with the car.

How to Re-Sync the Peugeot 308 Key Fob

Try this:

1. Sit inside the car.
2. Insert key into ignition (or hold near start button).
3. Turn ignition ON.
4. Press and hold the lock button for 10 seconds.
5. Turn ignition OFF.
6. Remove key and test.

In many cases, that restores communication instantly.

Push-Button Start Models: Special Considerations

If your 308 has keyless start, the car uses proximity detection.

If the battery is weak:

• Hold the key fob directly against the start button.
• Or place it in the designated emergency slot.

Even with a dead battery, the immobilizer chip often still works.

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Interference Issues: The Silent Signal Killer

Modern cities are full of radio waves.

Possible interference sources:

• WiFi routers
• Mobile towers
• Underground parking garages
• Security systems

If your key fob works elsewhere but not in one location, interference is likely the culprit.

Damaged Key Fob Circuit Board

Sometimes the issue is physical damage.

Causes of Internal Damage

• Dropping the key
• Water exposure
• Sitting on it repeatedly
• Excessive heat

If buttons feel loose or the casing rattles, internal solder joints may be broken.

At this point, repair or replacement may be required.

Peugeot 308 Car Battery Problems

Here’s something many overlook.

If the car’s battery is weak, it may not receive the key’s signal properly.

Symptoms of a Weak Car Battery

• Slow cranking
• Flickering dashboard
• Central locking issues

Test the vehicle battery before blaming the key.

Blown Fuse Affecting Central Locking

A blown fuse can disable remote locking.

How to Check

1. Locate fuse box (dashboard or engine bay).
2. Check central locking fuse.
3. Replace if blown.

Consult the owner’s manual for fuse diagram.

Immobilizer or BSI Module Issues

The Body Systems Interface (BSI) controls electronic communication.

If faulty:

• Key won’t be recognized
• Central locking fails
• Random electrical glitches occur

BSI resets sometimes fix minor glitches:

• Disconnect car battery for 15 minutes
• Reconnect carefully

But deeper faults require diagnostic tools.

When the Key Fob Buttons Are Worn Out

After years of use, buttons can physically fail.

Symptoms

• Button feels soft or flat
• Only works when pressed hard
• Rubber worn through

In this case:

• Replace casing shell
• Or replace entire fob

Fortunately, shells are inexpensive online.

Emergency Access When Key Fob Fails

Don’t panic.

Your Peugeot 308 includes:

• A hidden mechanical key
• Manual door lock access

Slide out the emergency blade and unlock the driver’s door manually.

Cost to Replace a Peugeot 308 Key Fob

Let’s talk money.

Estimated Replacement Costs

• New key from dealer: £180–£300
• Programming: £50–£100
• Aftermarket key: £70–£150

Dealer keys are safest but most expensive.

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Can You Program a Peugeot 308 Key Yourself?

Short answer: Usually no.

Most modern Peugeot keys require:

• Diagnostic software
• PIN code access
• Professional programming

DIY programming is rare on newer models.

Differences Between 308 Generations

The Peugeot 308 uses simpler remote systems.

The newer Peugeot 308 features:

• Advanced encryption
• Passive entry
• Enhanced immobilizer security

Newer systems are more secure—but more complex.

Preventing Future Key Fob Problems

Let’s stay ahead of issues.

Best Practices

• Replace battery every 2 years
• Avoid moisture exposure
• Don’t drop it
• Keep spare key functional
• Store away from magnets

Treat it like a tiny computer—because it is.

When to Visit a Peugeot Specialist

Seek professional help if:

• Key not detected message persists
• Car won’t start at all
• Central locking completely fails
• Warning lights appear

A full diagnostic scan can pinpoint faults quickly.

Quick Troubleshooting Checklist

Before replacing anything, ask:

• Did I change the battery?
• Did I try re-syncing?
• Is the car battery healthy?
• Are fuses intact?
• Does spare key work?

If spare key works, problem is isolated to the faulty fob.

Is It Safe to Drive With a Faulty Key Fob?

Yes—if:

• Immobilizer still works
• You can manually unlock
• Car starts normally

But convenience will suffer.

Final Thoughts: Don’t Panic, Diagnose

A Peugeot 308 key fob not working feels frustrating—but it’s rarely catastrophic. In most cases, a £2 battery fixes everything.

Modern cars are like smartphones on wheels. When something stops responding, we troubleshoot step by step. Calmly. Logically.

And most of the time, the solution is simple.

Fix the small things first.

Then escalate only if necessary.

That’s how we stay in control.

FAQs

1. Why is my Peugeot 308 key not detected?

Most commonly due to a dead battery in the fob. Try holding it near the start button.

2. What battery does a Peugeot 308 key use?

Most models use a CR2032 coin battery.

3. How do I reset my Peugeot 308 key fob?

Turn ignition ON and hold lock button for 10 seconds.

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4. Can water damage ruin the key fob permanently?

Yes. Internal circuit corrosion may require full replacement.

5. How much does a replacement key cost?

Between £180 and £300 from a dealership including programming.

If you want to know other articles similar to Peugeot 308 Key Fob Not Working: Complete Fix Guide you can visit the category Common Problems.