Keyless Go Not Working on Mercedes: Causes, Troubleshooting, and Solutions

Keyless Go is one of Mercedes-Benz’s most convenient features, allowing you to unlock, lock, and start your car without ever removing the key fob from your pocket or bag. When it stops working, it can be frustrating—especially if you rely on push-button start or hands-free access. This guide explains the common reasons why Keyless Go might fail on your Mercedes, step-by-step troubleshooting, and what you can do to fix it.

How Keyless Go Works

Keyless Go uses radio-frequency identification (RFID) and short-range antennas in the car and the key fob. When you touch the door handle or press the start button, your Mercedes “searches” for the presence of an authorized fob within a few feet. If detected, it allows entry and ignition. If not, the car remains locked or won’t start.

Common Reasons Keyless Go Stops Working

1. Weak or Dead Key Fob Battery
   • The most common cause. If the fob battery is low, the car may not detect the fob, or you’ll need to be much closer than usual for it to work. Some features (like remote lock/unlock) might still function, but Keyless Go won’t.
   • Mercedes will often show a “Key Battery Needs Replacing” message when battery is low.
2. Interference or Signal Blockage
   • Nearby electronics, cell phones, wireless devices, or metal objects can block or interfere with the fob’s signal.
   • Car parks with strong security gates or “RF-jammers” can also disrupt Keyless Go.
3. Key Fob Malfunction
   • Physical damage, water intrusion, or worn out electronics can cause your fob to stop transmitting or receiving signals properly.
4. Failed Keyless Go System in Car
   • Antenna or receiver faults, blown fuses, or software glitches in the car’s Keyless Go control module can cause failure. Sometimes, only one door/handle stops working, indicating a local antenna or wiring issue.
5. Multiple Fobs Nearby
   • If more than one Mercedes fob is very close to the car, or you’re carrying other keyless fobs, it can confuse the system.
6. Settings or Lockouts
   • Some models allow you to turn Keyless Go on or off via vehicle settings (in the COMAND or MBUX menu). It’s possible to accidentally disable the system.

Step-by-Step Troubleshooting Guide

1. Check the Key Fob Battery
   • Replace the fob battery with a fresh CR2025 or CR2032 (see your owner’s manual for the exact type). Even if the battery isn’t completely dead, low voltage can disable Keyless Go while regular lock/unlock may still work.
2. Test All Functions
   • Try all doors, the trunk, and the start button. If only one handle fails, the issue is likely with that handle’s antenna or sensor.
3. Eliminate Interference
   • Remove your fob from crowded pockets or bags with cell phones, chargers, or metal objects. Test again.
   • Try using the fob from both inside and outside the car, and in different locations.
4. Try the Spare Key
   • If you have a second key fob, test it. If the spare works and the main fob doesn’t, your original fob likely has an issue.
5. Reset the System
   • On some models, you can “reset” the Keyless Go system by locking and unlocking the car with the fob, or starting the car with the key fob inserted into the emergency slot after removing the Start/Stop button.
6. Check Vehicle Settings
   • Look in your infotainment system (COMAND or MBUX) for Keyless Go settings to ensure it’s enabled.
7. Inspect Fuses and Wiring
   • If none of the above work, check your owner’s manual for the location of the Keyless Go fuse(s) and inspect for any blown fuses. Also, inspect visible wiring or signs of water damage, especially near doors and trunk.

If All Else Fails

• Visit Your Mercedes-Benz Dealer or Qualified Specialist
  If your Keyless Go system still doesn’t work after trying all troubleshooting steps, it’s time for a professional diagnosis. The dealer can scan for error codes, check the Keyless Go antennas and modules, and update software if necessary.
• Replacement Parts
  If a key fob or Keyless Go module is defective, it will need to be replaced and reprogrammed by an authorized dealer.

Frequently Asked Questions

• Can I still drive my Mercedes if Keyless Go is not working?
  Yes. In most cases, you can still unlock your car using the physical buttons on the fob and start the car by holding the fob against the Start/Stop button or by inserting it into the ignition slot (after removing the Start/Stop button).
• Does a dead key fob battery affect driving?
  You can usually start the car even with a dead fob battery using the backup RFID chip in the fob; hold it against the Start/Stop button or insert as above.
• Can I fix Keyless Go myself?
  Battery, interference, and settings issues can often be solved at home. Antenna, wiring, or module problems usually require professional equipment and dealer attention.

Tips to Prevent Keyless Go Problems

• Replace key fob batteries every 1-2 years or at the first sign of low battery
• Keep fobs dry and avoid dropping them
• Do not store fobs near electronics or magnets for long periods
• Check for Mercedes recalls or software updates related to Keyless Go

Summary

If your Mercedes Keyless Go is not working, start by replacing the key fob battery and eliminating signal interference. Check the car’s settings and try a spare fob if you have one. If the problem persists, it may be a more serious issue with the car’s Keyless Go system, which will require diagnosis by a dealer or qualified specialist. Keeping your key fob battery fresh and avoiding interference will help ensure Keyless Go convenience every time you approach your Mercedes.