Key Fob issues
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2003 CLK500, 2008 e350
Key Fob issues
I have a 2012 E350. One of my key fobs stopped locking/unlocking the doors and trunk. The FOB still works to start the car. I’ve tried 3 different new batteries with not success. I have a second FOB that works fine.
Any suggestions will be appreciated.
Thanx, in advance, for any ideas as to what the problem might be.
Any suggestions will be appreciated.
Thanx, in advance, for any ideas as to what the problem might be.
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From: MA
2008 E350 4Matic, 2011 E350 4matic
Try playing around with the battery. Take it out and put it back in a few times. Press the button to see if you get a red light. Sometimes mine doesn't work but somehow putting it in a certain way/angle seems to get it to work again. Not sure exactly what it is, I've played with the pins a little but it doesn't seem to matter, sometimes putting it in makes it work, other times it doesn't. Takes a few attempts to get it working when just replacing the battery. Maybe it's too high, low, too far to the left or right, who knows.
The fob doesn't require a battery to start the car when you put it in the ignition.
The fob doesn't require a battery to start the car when you put it in the ignition.
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2008 E350, 2012 ML350, 2014 E350, 2015 ML350
to complement @cetialpha5 , once you see the red light it means the battery is (hopefully) sitting correctly. Then, you can point your phone's camera to the front of the key (the rectangular part that goes inside the ignition) and press the lock/unlock button and you MUST see the IR flashing in our camera. If you do not, the IR circuitry in the key fob is damaged.
You can always verify the advice with the working keyfob. Good luck.
You can always verify the advice with the working keyfob. Good luck.
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From: Dallas-Ft.Worth,TX
2016 E350 Sport
to complement @cetialpha5 , once you see the red light it means the battery is (hopefully) sitting correctly. Then, you can point your phone's camera to the front of the key (the rectangular part that goes inside the ignition) and press the lock/unlock button and you MUST see the IR flashing in our camera. If you do not, the IR circuitry in the key fob is damaged.
You can always verify the advice with the working keyfob. Good luck.
You can always verify the advice with the working keyfob. Good luck.
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2008 E350, 2012 ML350, 2014 E350, 2015 ML350
Does not work for me... The red LED confirms that the battery is good and properly seated. But, my phone camera aimed at the business end of the fob (straight on) shows no IR flashing. From the front of the fob (with the buttons) a phone camera sees the flashing LED, but you do not need a camera to see that...
I went to the garage and tested the keyfobs for the W212 and both passed the red LED, and the camera tests. They should since I alternate keyfob usage daily.
However, sister's W211 failed both miserably. So I changed the batteries and both tests passed. Here is the picture from the camera test on the W211 keyfob. Yours is up to something, and the working keyfob should pass both tests.
Thank you for pointing this out since I was unaware the W211 had discharged already.
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2008 E350, 2012 ML350, 2014 E350, 2015 ML350
I recall reading about these tests some time ago.
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From: MA
2008 E350 4Matic, 2011 E350 4matic
Did you also use a meter to make sure the new batteries have a decent voltage. Half the time the ones you buy at the store have been sitting there so long, they're already dead. Also in the worst case, you can stuff a 2032 in there. It's a tight fit and the door barely closes so I don't really like it, but it's a bigger battery and may have a better chance of making contact. I don't think the IR really matters.
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From: US
2008 E350, 2012 ML350, 2014 E350, 2015 ML350
Found the page with the information for the different tests:
https://www.mercedesmedic.com/merced...b-not-working/
5 tests:
1 - Battery, and LED. Plus check the batteries charge since "new" does not mean charged ( @cetialpha5 advice)
2 - IR test via phone (what I mentioned)
3 - Central locking fuse (which should work since the other key works)
4 - Resync the key (I have forgotten about this one, never had a need for it)
5 - Diagnostic tool/scanner
Against my practice of never messing with the reference condition/part, you can also swap batteries between the working fob and the not working fob at the risk of messing with the good one when doing so.
https://www.mercedesmedic.com/merced...b-not-working/
5 tests:
1 - Battery, and LED. Plus check the batteries charge since "new" does not mean charged ( @cetialpha5 advice)
2 - IR test via phone (what I mentioned)
3 - Central locking fuse (which should work since the other key works)
4 - Resync the key (I have forgotten about this one, never had a need for it)
5 - Diagnostic tool/scanner
Against my practice of never messing with the reference condition/part, you can also swap batteries between the working fob and the not working fob at the risk of messing with the good one when doing so.
Last edited by JCM_MB; Dec 31, 2022 at 11:42 AM.
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2016 E350 4Matic wagon, 2019 Ford Expedition, 2019 Chevy Bolt EV
if you use a 2032 in place of a thinner 20xx, get in the habit of always using a 2032 in that device, as its going to compress the battery contact spring so it may not work as well with a 2025 or whatever next time.
btw, i've used 2032's in a LOT of 2025 devices, and 90% of them fit just fine. The 2032 will last about twice as long. I believe the correct battery type is CR, which are lithium (non-rechargable, not the same as Li-Ion or whatever). and 3.0V new, 2.0V when at end of useful life.
btw, i've used 2032's in a LOT of 2025 devices, and 90% of them fit just fine. The 2032 will last about twice as long. I believe the correct battery type is CR, which are lithium (non-rechargable, not the same as Li-Ion or whatever). and 3.0V new, 2.0V when at end of useful life.
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From: Dallas-Ft.Worth,TX
2016 E350 Sport
if you use a 2032 in place of a thinner 20xx, get in the habit of always using a 2032 in that device, as its going to compress the battery contact spring so it may not work as well with a 2025 or whatever next time.
btw, i've used 2032's in a LOT of 2025 devices, and 90% of them fit just fine. The 2032 will last about twice as long. I believe the correct battery type is CR, which are lithium (non-rechargable, not the same as Li-Ion or whatever). and 3.0V new, 2.0V when at end of useful life.
btw, i've used 2032's in a LOT of 2025 devices, and 90% of them fit just fine. The 2032 will last about twice as long. I believe the correct battery type is CR, which are lithium (non-rechargable, not the same as Li-Ion or whatever). and 3.0V new, 2.0V when at end of useful life.
My key fobs have functioned perfectly since I've had my car, and I replaced the battery in my primary fob just last month with (tested in front of me) batteries from Batteries Plus.
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2016 E350 4Matic wagon, 2019 Ford Expedition, 2019 Chevy Bolt EV
I don't see anything when I push the unlock button on the fob, AFAIK, that IR is only used when you insert the key into the ignition thing... the remote door lock/unlock stuff is all RF
I checked my cell camera against a tv remote control, and it certainly sees that IR as a sort of lavender color.
I checked my cell camera against a tv remote control, and it certainly sees that IR as a sort of lavender color.
Last edited by Left Coast Geek; Dec 31, 2022 at 05:37 PM.
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2008 E350 4Matic, 2011 E350 4matic
I believe there's also a sensor in front of the driver's door and if you hold the lock/unlock button down, all the windows either go up or down and sunroof will open/close. I don't think IR needs to work in order to start the car as it uses RFID which doesn't need a battery.
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heh, even my 1990 W124 300E had that feature, hold the drivers key in unlock, all windows go down, hold it in lock, all windows close. US models of those cars had no remote fob, just key locks, the locks were pneumatically operated.
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From: Dallas-Ft.Worth,TX
2016 E350 Sport
I don't see anything when I push the unlock button on the fob, AFAIK, that IR is only used when you insert the key into the ignition thing... the remote door lock/unlock stuff is all RF
I checked my cell camera against a tv remote control, and it certainly sees that IR as a sort of lavender color.
I checked my cell camera against a tv remote control, and it certainly sees that IR as a sort of lavender color.
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From: Dallas-Ft.Worth,TX
2016 E350 Sport
I thought that Keyless-Go became standard on W212 with the facelift model (2014+). Available only with the P2 option on cars prior.
Someone with better info can clarity...
Someone with better info can clarity...
Last edited by DFWdude; Dec 31, 2022 at 09:20 PM.
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From: 122W, 37N
2016 E350 4Matic wagon, 2019 Ford Expedition, 2019 Chevy Bolt EV
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2008 E350, 2012 ML350, 2014 E350, 2015 ML350
I do not have keyless-go in my 2014 w212, but the w211 has it. Both keys have the lavender color when the lock/unlock is pressed.
Happy New Year to all
Happy New Year to all
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2014 - W212.065 - E400 ( M276.820, 3 liter Turbo) RWD not Hybrid
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the one without keyless go, did it use the same style fob ? you can remove that 'push to start' button from any keyless go car, and it then requires you to use the fob as a key.
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W212 FL
if you use a 2032 in place of a thinner 20xx, get in the habit of always using a 2032 in that device, as its going to compress the battery contact spring so it may not work as well with a 2025 or whatever next time.
btw, i've used 2032's in a LOT of 2025 devices, and 90% of them fit just fine. The 2032 will last about twice as long. I believe the correct battery type is CR, which are lithium (non-rechargable, not the same as Li-Ion or whatever). and 3.0V new, 2.0V when at end of useful life.
btw, i've used 2032's in a LOT of 2025 devices, and 90% of them fit just fine. The 2032 will last about twice as long. I believe the correct battery type is CR, which are lithium (non-rechargable, not the same as Li-Ion or whatever). and 3.0V new, 2.0V when at end of useful life.
