Is your Mercedes-Benz key fob not working? The first thing to check is whether the keyless remote battery needs to be replaced. If your Mercedes key fob isn't working after a battery replacement, we have some suggestions that will assist you in troubleshooting issues with the Mercedes key fob not functioning or no longer unlocking or locking doors or trunks. This article focuses on problems with Mercedes-Benz c250 2008, CLK, CLS, A160, C-Class C220, 230, 300 and CLS models.

Common Reasons Why Mercedes Benz key fob not working

  • Mercedes key fob not working after changing the battery
  • Mercedes remote stopped working
  • The car's keyless remote does not lock or unlock the automobile
  • Mercedes key fob will not open the doors
  • The panic button and/or trunk opener aren't functional

How to Fix a Mercedez Key Fob That Isn't Working

Step 1: Check the remote key.

Make sure your key fob has fresh batteries. Then take a look at your Mercedes-Benz key. When you press the button on your key, you should see a tiny RED LED light. The light should go on whenever you press any of the buttons (Lock, Unlock, Panic, or Trunk).

Step 2: Check for an infrared signal with your phone.

We must now see whether the remote is sending a signal. The remote uses infrared rays. Infrared light cannot be seen with the naked eye, but there is a simple technique to check for it. Take your phone and turn on the camera. When you point your smartphone's camera at it, carefully watch for a light every time you press a button on the remote. If there is no light, the key is broken. If you detect any light, it's likely that the problem lies elsewhere, so please proceed to the next step.

Step 3: Check for a central locking fuse

Remove the metal key from the Mercedez key fob and use it to manually unlock the doors. The next step is to inspect the central locking circuit's fuse. Look also at your car's antenna module and AAM fuses. Because your MB gets its lock / unlock signal via antennas on your vehicle, a defective antenna module fuse can cause your Mercedes key fob to stop working.

The MB class determines where the fuse is found, but it can be found in one of the engine bays, dashboard, under the rear seat, or trunk. If you detect a blown fuse, replace it. Always replace blown fuses with the same ampere rating. Don't use a higher ampere rating than is necessary.

Step 4: Program / Synchronize the Remote

Simply press and hold the button for a few seconds to sync a Mercedes-Benz key to your automobile. This works in most cases, but you may occasionally need to follow extra instructions to link your key fob remote with your vehicle. Even new keys bought from the dealer should work as advertised after you put them into the ignition. There are several circumstances when you'll need to sync your key fob remote to your Mercedes-Benz car. Check your owner's handbook for more specific instructions.

Step 5: Check all activity modules (AAM)

The last stage is to identify the AAM module. This is where this repair might get pricey since you'll either have to go to a professional or buy diagnostic scanners. You'll need to begin by reading the fault codes from the AAM module. You can do this with a diagnostic scanner like iCarsoft MB II, which hopefully allows you to identify and repair the issue with yourself.

If the AAM module is faulty, or if programming is required, the iCarsoft MB II scanner will be of little assistance. You'll either need to bring your Mercedez Benz to a shop that has an MB Star Diagnostic Scanner or an advanced scanner like Autel Maxidas or SnapOn Solus.

Where to Get New Replacement Key for Mercedes Benz in Las Vegas?

If you are looking for a new replacement key for your Mercedes Benz c250 2008 key fob, USA Lock and Key can help. 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 in Las Vegas, and we can help you get your car back on the road quickly and easily. Contact us today to learn more about our services!