How to Replace the Key Fob Battery in a 2018 BMW 330i

Introduction

If your 2018 BMW 330i key fob has stopped working or has a weak signal, the battery is likely dead. Instead of going to a dealership and paying for a replacement, you can easily swap out the battery yourself in just a few minutes.

This guide will walk you through the step-by-step process of opening the key fob, replacing the battery, and reassembling it correctly. The process is simple, requires only a small flathead screwdriver, and will help you restore full key fob functionality.

What you need

Step 1 Key Fob Battery

How to Replace the Key Fob Battery in a 2018 BMW 330i, Key Fob Battery: step 1, image 1 of 2

How to Replace the Key Fob Battery in a 2018 BMW 330i, Key Fob Battery: step 1, image 2 of 2

Press the small button on the back of the key fob to release the mechanical key.
Pull the key out completely.

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Step 2

Insert the mechanical key into the slot and gently twist it to pry open the key fob case.
Be careful not to use excessive force, as this may damage the plastic casing.

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Step 3

Once the key fob is open, you will see the CR2450 battery inside. Make a note of its positive (+) and negative (-) orientation.
Carefully remove the old CR2450 battery by lifting it out with a nylon spudger or your fingernail.
Avoid using sharp metal tools to prevent damage to the battery compartment.

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Step 4

How to Replace the Key Fob Battery in a 2018 BMW 330i: step 4, image 3 of 3

Place the new CR2450 battery in the correct orientation, with the positive (+) side facing up.
Ensure the battery is properly seated in the battery slot.
Double-check that the battery is positioned correctly before closing the key fob.

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Step 5

Align the two halves of the key fob and press them firmly together until you hear a click.
Ensure all edges are securely snapped back into place.

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Step 6

Slide the mechanical key back into the key fob until it locks into place.
Press the lock/unlock buttons to ensure the key fob is working.
If the key fob does not respond, recheck the battery installation to ensure it is properly seated.