When you're driving a Mercedes Benz, you expect nothing but the best. You want to know that your car is in good hands and that it's always going to work exactly as it should. But what happens when something breaks?

Is your Mercedes Benz Key Fob not working? Do you have a faulty key fob control system? Don't worry, USA Lock & Key is here to help! We'll walk you through some of the most common problems with these systems, and show you how to diagnose them so that you know what's going on before heading into the shop. Here are some of the most common issues:

Reasons Why the Mercedes Benz Key Fob Is Not Working

  • The key fob doesn't work even after battery replacement
  • It no longer unlocks or locks the vehicle
  • Your Key Fob cannot open the doors
  • The panic button and/or trunk opener is no longer working

These are a few reasons why your key fob might not be working. And there are also several solutions to fix this problem. If these solutions don't work, then you might need a Mercedes key fob replacement. But first, let's start with the fixes.

Possible Fix For Your Mercedes Benz Key Fob

If your key fob is not working, there are a few things you can try.

Check the Batteries

First, check the batteries. The key fob usually lasts around 3-4 years and is the same for luxury vehicles. Try replacing it with new batteries and check if there is a red light whenever you try to press a button (lock, unlock, panic button, trunk button). If a red light is visible and it works, then you just needed a battery replacement. However, if it doesn't, continue to the next fix.

Check the Infrared Signals

The infrared signal that is emitted from your key fob is a handy way to check for problems with your key fob. If you have a red light on your key fob, then it means that a signal is being sent out and received by your car's system using infrared rays for unlocking, locking, etc.

You can use your phone camera to check the infrared signal coming from your key fob. Point your camera towards the top front of your key fob and press a button. If you see any light on the camera after pressing a key fob, then the problem lies elsewhere. And if you don't see any light on the camera, the key fob is defective.

Check the Central Locking Fuse

One of the most common problems with Mercedes Benz key fobs is that they stop working or lose their range. The first thing you need to do is check the central locking fuse. This fuse powers up the antenna module and also controls the key fob's functions.

The first step is to remove the metal key from your key fob and use the metal key to manually unlock your doors. After that, check for the fuse of the central locking circuit. Keep in mind that you should also check the Antenna Module of the car, as well as, the AAM (All Activity Module) fuses. Although it depends on what Mercedes Benz model you have, you can try looking at the engine bays, under the rear seat, dashboard, or trunk. 

Now, the reason why you need to check these is that your vehicle gets its unlock/lock signal via the antenna modules. When you have a broken module fuse, this can cause your key fob to stop working. In addition, repairing is not an option so it's best to replace it immediately with the same ampere rating and never higher than your previous one.

Programming or Synchronizing the Key Fob

After replacing the fuse, try programming or synchronizing your key fob. The first way to do this is by inserting the key into your ignition for a few seconds and the car's system will synchronize by itself. However, this doesn't work all the time and you might need to follow these general instructions:

  • Insert the key into your car's ignition.
  • Remove the key immediately and after 10 seconds hold down your lock button.
  • While holding down your lock button, press your unlock button 5 times. Keep in mind that you should still be holding the lock button while consecutively pressing the unlock button.
  • After that, release the button and press the trunk button a single time. 
  • Try testing if your unlock or lock functions are working. If it does, then your key fob is synchronized. 

Now, this is only a general instruction and this might not work on your Mercedes Benz model. To check on how to synchronize for your model, try checking it on your owner's manual, or if you lost it, check here.

Check the All Activity Module

The last fix is checking the All Activity Module or AAM. Normally, not everyone has a diagnostic scanner like iCarsoft MB II or MB Star Diagnostic Scanner, nor do they have the knowledge of reading codes on a diagnostic scanner. However, if you do have the tools and knowledge, you can begin by reading the faulty codes from the AAM module through the scanner. By doing this, you can identify and repair the problems of your car system and key fob on your own. Now if the AAM module is malfunctioning, a diagnostic scanner will not help as its job is only to scan, read, and clear codes. 

Moreover, if you don't have the budget to buy these tools or don't have the knowledge or time to learn how this works, it's best to call a professional to fix the issue and program a new key fob for your vehicle.

Where To Find a Cheap Mercedes Key Fob Replacement?

The first way to get a key fob for your Mercedes Benz is through a car dealership. Usually, Mercedes Benz owners call a dealership because they do not know a locksmith can program and make a new key for their vehicle. In addition, they may have called a few locksmiths and those locksmiths have declined them as they are not knowledgeable about the complex system a Mercedes has.

Now opting to go for a car dealership to program new key fobs is not ideal. The first reason is that car dealerships will cost more. This is because they do not have an inventory of key blanks for key duplication. The second reason is that it will take longer as car dealerships will request your car's VIN Number at NHTSA's VIN Decoder which usually takes 3-5 days. And lastly, most of the time, a car dealership will outsource the work to an automotive locksmith.

The second way is opting for an automotive locksmith for a Mercedes Key Fob replacement. An automotive locksmith is an ideal choice as they can arrive at your location within 30 minutes, make/program new key fobs without the need for a VIN number, and you'll be back on the road in no time. While it's still not cheap, a new key fob from a locksmith will cost less than a car dealership.

In Need of a Mercedes Key Fob Replacement?

Is your Mercedes Benz key fob not working? Contact USA Lock & Key for all of your automotive locksmith needs in Las Vegas. We offer a variety of services for Mercedes owners, including key fob replacement for all Mercedes models, Mercedes Benz ignition key troubleshooting, key fob programming, and more. 

We have years of experience in the automotive locksmith industry, and we can help you get your car back on the road quickly and easily. Contact us today to learn more about our services! In need of a Mercedes key fob replacement? Don't hesitate to reach out to USA Lock & Key - we're here to help!