Key fob signal/communication issue
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Joined: Oct 2025
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2011 E350 Wagon
Key fob signal/communication issue
My wife’s 2011 E350 wagon is having an issue with the vehicle recognizing her key fob. It started as a message on the dash while driving and was initially intermittent. It is now continuous, requiring her to insert the key in the ignition every time to start the vehicle. In addition it is now difficult to lock or unlock the vehicle using the fob. You have to walk around the vehicle continuously hitting the lock/unlock button until you can find the right spot that it will receive the signal. Previously we could lock/unlock from inside the house 30 ft away.
The car came with 3 key fobs when we bought it. So logically I switched the fob and put in a fresh battery. I tried all 3 key fobs and continue to have the issue.
This leads me to believe it may be an issue with the antenna or ECU receiving the signal from the fob. Has anyone else had a similar experience, or any additional insight?
The car came with 3 key fobs when we bought it. So logically I switched the fob and put in a fresh battery. I tried all 3 key fobs and continue to have the issue.
This leads me to believe it may be an issue with the antenna or ECU receiving the signal from the fob. Has anyone else had a similar experience, or any additional insight?
MBWorld Fanatic!
Joined: Dec 2011
Posts: 4,373
Likes: 945
W212 FL
3 key fobs ? It must be 2 , not 3 at least I have not seen 3 key fobs working all the time . Besides, when you see the message " key fob not recognized" just try these :
1- Press unlock button on the key fob
2- Press lock button on the key fob
3- Press unlock button on the key fob
Please press these buttons once at a time
Mine acted weirdly after key fob battery replacement, I tried the trick above and it's finally started to work flawlessly since then
1- Press unlock button on the key fob
2- Press lock button on the key fob
3- Press unlock button on the key fob
Please press these buttons once at a time
Mine acted weirdly after key fob battery replacement, I tried the trick above and it's finally started to work flawlessly since then
Out Of Control!!
Joined: Apr 2019
Posts: 11,924
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
exhausted keyfob power
The Engine Control Unit is not involved with the keyfob security handshakes.
Report to the local Mercedes Dealer for a coin cell battery service.
In the mean time insert key fob in key slot works safely to keep ignition active.
Report to the local Mercedes Dealer for a coin cell battery service.
In the mean time insert key fob in key slot works safely to keep ignition active.
