How to Replace the Battery in an Older Mercedes-Benz E320-CDI Key?
3 Answers
Here are the specific steps to replace the battery in an older Mercedes-Benz E320-CDI key: 1. First, flip open the tab at the rear end of the key to remove the mechanical key. 2. Insert the mechanical key into the side slot of the key, press the internal gray button, and with the other hand, push the rear end of the key upward. When a gap opens, remove the mechanical key. 3. Then, manually take out the rear end. After replacing it with a new battery, reinsert the key holder, and the battery replacement is complete. Note: The lifespan of a Mercedes-Benz key battery is typically two years, while the original factory battery can last up to six years.
Replacing the battery in an older Mercedes E320-CDI key is actually quite straightforward, as I've done it myself on similar models. First, identify the key type—most are either folding or remote keys. Locate the small groove or screw slot on the back cover of the key. If you don't have tools, gently pry it open using a credit card or thin plastic piece from the seam. Inside, you'll find a CR2032 coin battery. Remember the orientation of the old battery, such as the positive (+) mark facing upward. After removing the old battery, wipe the contacts with a dry cloth. Align the new battery correctly, ensuring the polarity isn't reversed, then press the cover back firmly. Test the remote range by pressing the buttons afterward—ideally, try the unlock function from about 10 meters away. The whole process takes about 5 minutes. The battery costs just a few dollars at a supermarket, saving you hundreds compared to a dealership visit. Be careful when prying open the plastic key casing, as it can age and crack—go slowly. Regularly replacing the battery extends the key's lifespan, and checking it once a year ensures safety.
I've encountered this issue too. My old Mercedes key frequently needs battery replacements. There's a small notch on the back of the key - I just gently pry it open with a small metal piece or my fingernail. The battery inside is a CR2032, so make sure you don't get the wrong model when purchasing - you can find them at convenience stores. When removing the old battery, check the positive/negative orientation, then align the new one properly before pressing the cover back on. After replacement, test the remote buttons. If the light doesn't come on, the battery might be reversed or the contacts could be dirty (just clean them with a cotton swab). The key responds faster with a fresh battery - I keep several spares at home for convenience. For E320 keys, there's usually no complex chip involved, so battery replacement won't affect settings. The whole process is simple and takes about 5 minutes. Since battery life is short, remember to check periodically to avoid remote failure when parking. DIY replacement is both cost-effective and reliable - no need to visit a professional shop.
