Key Lock/Unlock Program
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Junior Member
Joined: Nov 2015
Posts: 17
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E350
Key Lock/Unlock Program
Hey guys, I got a 2006 E350 (non-Keyless Go) and replaced the dead batteries on one of my keys. The key works starting the car but doesn't lock or unlock. I held the lock and unlock button together for a couple seconds and it flashed the red light slowly then stopped. How do you program to lock and unlock? Thanks
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From: In the Shadow of the Tetons
2013 ML350 Bluetec
holding the lock/unlock button on the key fob for several seconds will change the behavior of the fob in unlocking the doors. It changes it from unlocking all of them with one click to unlocking only the driver's door with the first click and the rest of the doors with a quick follow-up click. Hold both buttons again and it reverts back to the original - unlocking all the doors with one click.
On getting the key to work again: (I totally copied the following from another forum...)
Or try this, from another site:
Let us know if it works.
If it doesn't, Google is your friend.
On getting the key to work again: (I totally copied the following from another forum...)
How to Program Mercedes Remote Keys
The transponder chip inside the key must be synchronized to the cars
immobiliser (for starting car) to proceed with these steps.
1. Place transmitter key in ignition lock and turn to position 2
2. Extract transmitter key from ignition lock
3. Within 10 seconds:
press (close) pushbutton, hold and simultaneously press (open)
pushbutton five times one after the other release pushbuttons and then
press one of the two pushbuttons once
It may also be necessary to synchronize a transmitter key if the
battery in the transmitter key has been replaced.
The transponder chip inside the key must be synchronized to the cars
immobiliser (for starting car) to proceed with these steps.
1. Place transmitter key in ignition lock and turn to position 2
2. Extract transmitter key from ignition lock
3. Within 10 seconds:
press (close) pushbutton, hold and simultaneously press (open)
pushbutton five times one after the other release pushbuttons and then
press one of the two pushbuttons once
It may also be necessary to synchronize a transmitter key if the
battery in the transmitter key has been replaced.
1 Place your key in the car's ignition and turn the key two clicks to the "On" position for any Mercedes car.
2 Press and release the lock button on your Mercedes keyless remote.
3 Press and hold the unlock button on your remote.
4 Press the lock button on your remote five times consecutively, while the unlock button is still held, at one or two second intervals.
5 Release the two buttons and wait five seconds after pressing the lock button for the fifth time. Press either the lock or unlock button once to finish the
2 Press and release the lock button on your Mercedes keyless remote.
3 Press and hold the unlock button on your remote.
4 Press the lock button on your remote five times consecutively, while the unlock button is still held, at one or two second intervals.
5 Release the two buttons and wait five seconds after pressing the lock button for the fifth time. Press either the lock or unlock button once to finish the
If it doesn't, Google is your friend.
Senior Member
Joined: May 2014
Posts: 485
Likes: 31
From: Concord, CA
'13 E350 . M276
Erik, your car key will start car without batteries, you could test this by removing batteries and trying it out. From your description, sounds like your new replacement batteries are bad. This happened to me and I thought my key had gone bad since batteries were new. When I finally changed both batteries a month later, all was well.
Thread Starter
Junior Member
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Posts: 17
Likes: 1
E350
Erik, your car key will start car without batteries, you could test this by removing batteries and trying it out. From your description, sounds like your new replacement batteries are bad. This happened to me and I thought my key had gone bad since batteries were new. When I finally changed both batteries a month later, all was well.
Senior Member
Joined: May 2014
Posts: 485
Likes: 31
From: Concord, CA
'13 E350 . M276
Ok, so bad batteries theory is out. Do you have a second key that you can test? If you don't, it could be one of two things, either you have a bad key that needs to be replaced or you have problems with your InfraRed (IR) system. These are several threads on IR problems. Just do a search for "remote key won't unlock doors." Below this thread under
Similar Threads" heading, there are some relevant threads, checkem out!
Replacing a key could run anywhere between $150-$250, just depends on where stealer is located!
Similar Threads" heading, there are some relevant threads, checkem out!
Replacing a key could run anywhere between $150-$250, just depends on where stealer is located!
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Junior Member
Joined: Aug 2003
Posts: 31
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From: Austin, Texas
05/CDI, 08/957S, 07/997-4S, 16/RRS/TD6, 23/9Y0/TSH
I think the infrared is used only to open/close all window and sunroof. You hold the key close to the door handle that has a infrared window and press the open button and hold for until all windows and sunroof opened.
The door locking/unlocking is using RF still.
The door locking/unlocking is using RF still.
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Super Member
Joined: Oct 2012
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From: Hollywood, CA
W209, W124
Is it possible that you scraped a piece off when you pulled the PCB out or put it back in?
As mentioned there are 2 separate systems that can unlock the doors. The rf part works at range and doesn't need line-of-sight. It uses the same antenae as radio. So if you try radio and stations are weak/staticy, you may have blown fuse or have bad antenae.
But key should still work when you aim at door handle and push buttons. If you hold unlock it should put all windows down.
And I 'm pretty sure that the little red light should flash briefly when you push the unlock and lock buttons.
But if 2nd key works fine, then likely that bad one is partially broken. May be possible to repair it.
As mentioned there are 2 separate systems that can unlock the doors. The rf part works at range and doesn't need line-of-sight. It uses the same antenae as radio. So if you try radio and stations are weak/staticy, you may have blown fuse or have bad antenae.
But key should still work when you aim at door handle and push buttons. If you hold unlock it should put all windows down.
And I 'm pretty sure that the little red light should flash briefly when you push the unlock and lock buttons.
But if 2nd key works fine, then likely that bad one is partially broken. May be possible to repair it.
Thread Starter
Junior Member
Joined: Nov 2015
Posts: 17
Likes: 1
E350
Is it possible that you scraped a piece off when you pulled the PCB out or put it back in?
As mentioned there are 2 separate systems that can unlock the doors. The rf part works at range and doesn't need line-of-sight. It uses the same antenae as radio. So if you try radio and stations are weak/staticy, you may have blown fuse or have bad antenae.
But key should still work when you aim at door handle and push buttons. If you hold unlock it should put all windows down.
And I 'm pretty sure that the little red light should flash briefly when you push the unlock and lock buttons.
But if 2nd key works fine, then likely that bad one is partially broken. May be possible to repair it.
As mentioned there are 2 separate systems that can unlock the doors. The rf part works at range and doesn't need line-of-sight. It uses the same antenae as radio. So if you try radio and stations are weak/staticy, you may have blown fuse or have bad antenae.
But key should still work when you aim at door handle and push buttons. If you hold unlock it should put all windows down.
And I 'm pretty sure that the little red light should flash briefly when you push the unlock and lock buttons.
But if 2nd key works fine, then likely that bad one is partially broken. May be possible to repair it.
Btw my other key, which is the one I typically use, works fine. The key in question is the spare.
