Replacing the battery in your 2004 BMW 745Li key fob can seem daunting, but it’s a straightforward process you can handle yourself. This guide will walk you through each step, ensuring you can get your key fob working again without a trip to the dealership. Understanding how to maintain your key fob is essential for the convenience and security features of your BMW 745Li.
Identifying Your BMW 745Li Key Fob Battery
The key fob for the 2004 BMW 745Li, often associated with the CAS 1 system, uses a CR2025 battery. This is a common type of coin cell battery, readily available at most drugstores, supermarkets, and online retailers. Knowing the correct battery type is the first step in ensuring a smooth replacement process. Using the wrong battery type can lead to improper function or even damage your key fob.
Step-by-Step Battery Replacement Process
Replacing the battery in your 2004 BMW 745Li key fob is a simple procedure that should take only a few minutes. Here’s how to do it:
- Gather Your Tools: You will need a small flathead screwdriver or a similar thin tool to open the key fob casing. Having a soft cloth can also be helpful to prevent scratches.
- Open the Key Fob: Locate the small notch on the side of your BMW 745Li key fob. Gently insert the flathead screwdriver into this notch and twist carefully to pry the two halves of the fob apart. Avoid using excessive force, as you could damage the plastic casing.
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Alt Text: Opening the 2004 BMW 745Li key fob casing to access the battery compartment.[/center]
- Remove the Old Battery: Once the key fob is open, you’ll see the CR2025 battery. Note the orientation of the battery (+ side up) before removing it. You can use your fingertip or the edge of the screwdriver to gently lift the old battery out of its compartment.
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Alt Text: Removing the old CR2025 battery from the 2004 BMW 745Li key fob.[/center]
- Insert the New Battery: Take your new CR2025 battery and insert it into the compartment, ensuring the + side is facing up, matching the orientation of the battery you just removed. Push down gently to make sure it is securely in place.
- Close the Key Fob: Carefully align the two halves of the key fob casing and press them firmly back together until they snap closed. Ensure there are no gaps and the casing is securely sealed.
Testing Your Key Fob
After replacing the battery, test all the buttons on your 2004 BMW 745Li key fob – lock, unlock, trunk release, and panic alarm – to ensure they are functioning correctly. If your key fob still doesn’t work after a battery replacement, there might be other issues, such as programming problems or a faulty key fob unit.
When Battery Replacement Isn’t Enough: Considering a New Key Fob
While battery replacement solves many common key fob issues, sometimes the problem lies deeper. If you continue to experience issues after replacing the battery, it might be time to consider a replacement key fob. Especially if your original key fob is old or has been heavily used, internal components can wear out over time.
A new aftermarket key fob, like the BMW-19-315-CAS1, can be a cost-effective solution. These aftermarket options are designed to be compatible with your 2004 BMW 745Li (and other models within the 7 Series from 2002-2008) and offer the same keyless entry functions as your original remote, including lock, unlock, trunk release, and panic alarm. They operate at a frequency of 315 MHz and are designed for vehicles with a push-to-start/stop button and proxy keyless entry system.
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Alt Text: A new aftermarket replacement key fob for a 2004 BMW 745Li, highlighting its features and compatibility.[/center]
Keep in mind that aftermarket key fobs typically require professional programming by a locksmith. Dealers may sometimes refuse to program aftermarket remotes. Also, the emergency insert key included with a new fob will need to be cut to match your vehicle’s ignition.
Finding Professional Help
If you need a new key fob programmed or encounter issues you can’t resolve yourself, seeking professional help is advisable. Automotive locksmiths specialize in key and remote programming and are often more affordable and accessible than dealerships. They have the necessary equipment and expertise to program aftermarket key fobs for your 2004 BMW 745Li. You can search for local locksmiths online to find a professional who can assist you with your BMW key fob needs.
By following these steps, you can confidently handle your 2004 Bmw 745li Key Fob Battery Replacement and understand when a full key fob replacement might be necessary. Maintaining your key fob ensures you continue to enjoy the convenience and security features of your BMW.
