Mercedes Remote Keys and Fobs

[redspecial2000]

Hi,

I have two remote fob keys for my SLK 230 that no longer work. Im down to my emergency key to switch my alarm on and off!!

Is there anyone out there that can either repair them or reprogram them?

Thanks,

S

 

[jaymanek]

The dealer!

 

[guydewdney]

i take it you have replaced the battery?

then re- sync'd it to the car (details in your owners manual - somthing like zap, unlock mechanical door lock, turn ign within 30 seconds)

ymmv...

Guy

 

[redspecial2000]

sorted!

Hi guys,

it turned out to be a combination of three things:

1. Low power in battery

2. The side battery contact (-ve) had pushed so far back over the years that it only allowed power every 7th or 8th press

3. A little resynch was needed

All sorted now, and achieving greater distances of operation!!

Thanks

 

[anyweb]

i still havent found out how to resync my key...

and unfortunately my owners manual is in german so even though i can see the page of the manual, i dont understand what they are saying...
help !

heres the text more or less in german

eine synchronisation kann notwendig werden, wenn ein sender fur mehrere minuten ohne spannung war.

Dazu sender auf den empfanger der tur oder des kofferraumes richten und sendetaste kurz drucken.

innerhalb von ca. 30 sekunded den schlussel im lenkschloB in stellung drehen.

danach ist die inrarot-fernbedienung wieder einsatzbereit.

 

[jberks]

Which model and year?
they vary slightly but basically, zap, then put key in and switch on the ignition within 30 seconds and then switch off - then zap again and hopefully all will be well. Sometimes takes a couple of attempts. My German is pretty poor but its definately 30 seconds!

 

[anyweb]

ok i'll try that

its a merc c220 from 1995

cheers

anyweb

 

[pascal]

Press the open button or close button twice in sucession on fob.
Within 15 sec of this, turn key in ignition '2'

Thats it. I prefer to use the open button, cause its easier to get into the car.:lol:

 

[anyweb]

hi pascal and thanks

but my key only has one button, if i press it twice it will 'close' the car (as it will first open it, then on the second click close it)

so what should i do ?

cheers

anyweb

 

[jberks]

Ah - another 95 c220 owner - I found them quite rare when I got mine.
As pascal says, just press the one button twice (pointing the sender at the interior mirror as you do) and then on with the ignition.

Your comment about pressing it twice is confusing - if you press it once to open and then again to lock - this implies its working fine - so why are you asking? Clearly if it isn't working, it doesn't really matter how many times you press.

You can test the fob by looking at the sender (red glass) and pressing and holding the button. After a few seconds you should see a red bulb flash. If you don't, the remote isn't working and at the very least you need a new battery - but in any case, you'll be wasting your time recyncing.

We have regular fun with the fob on our 95 C220. It does seem to need a recync every 6 months or so but generally works fine other than that.
Because its a single button, the buttons do tend to wear out. You find you just have to press harder after a while, then eventually it starts to become intermittent and you have to replace it (never attempted a repair, but with a soldering iron and a friendly local maplin - who knows!). I had both of mine replaced (had an extended signature warranty at the time) a few years ago and it's been ok since. - so long as we recync when it starts to play up.
Your dealer can do a system reset if its still not working. Not sure of a 30 min disconnect of the battery has the same effect.

 

[anyweb]

hi jberks

my problem is that after i replaced the batteries in the key, when i press the button on it to open or close the car, it normally works, however this morning when i pressed it to 'close' the car, nothing happened, nada, zilch, 6 presses before it registered,

also, more worrying to me is now since changing the batteries in the key, when i press once to open (or again to close) the LEDs on the rear view mirror flash RED/GREEN for ages either while im starting the car or getting out of it and locking it

this to me tells me i have a problem, but i cannot figure it out

cheers

anyweb

 

[jberks]

I suspect the button on the remote is on the way out. The red+green flash is supposed to indicate that the battery on the remote is weak, but as you say, you've just replaced them.
Assuming (guessing) that it does this by detecting a weak signal, if the switch is poor, it will take a few attempts to get anything out of it and even then if the contact is poor, the symptoms may be similar to a poor battery - hence the car is mis-interpreting a low battery and flashing both lights. I found the 2 light warning did happen occasionally anyway but certainly not every time. You may be able to tell by gently pushing the button and watching for the red led to light up. It should give an indication as to whether the switch is working each press or not.

You probably already know this, but just in case you don't, the reciever is in the interior mirror so you must point the transmitter at the mirror and ensure the mirror glass is clean.

 

[anyweb]

this problem has returned to haunt me, seems like a winter thing even though winter isnt here yet....(close, but not yet)

only thing that has changed between now and then is i changed the car battery with a new one, after that the leds were fine for ages

so... my battery is now less than a year old (car battery) am I now to consider that it is failing again ? the fob batterys are fine still shining a bright red when i press and hold.

cheers
anyweb

 

[jberks]

Hi anyweb.
Never give up on a remote. My Dad's experience is that he's got ones working now that were decalred dead by the dealer.
The 2 flashing lights used to happen to me occasionally for no apparent reason. Provided the alarm sets (which it does) you are pretty safe to ignore it.
Perhaps pop a new battery into the remotes anyway and I'd also dis the car battery for 30 mins then resync the remotes again. We tend to find that this gets them all working again - at least it hasn't failed us yet.
The other thing my Dad noticed is that if a key isn't used for a while, it no longer works, so he now rotates his 3 keys every few weeks.

 

[Fandango]

Translation:
Synchronisation can be necessary if power is lost for a few minutes.

In order to achieve this point the sender at the receiver on the boot lid or the door and press send button briefly.

Turn the key in the ignition within 30 sec.

Bob's your uncle.

HTH

 

[anyweb]

ok ive tried re-synching both keys, with the same results from both

so what next ? do i disconnect my car battery for 30 mins as jberks suggests ? or are the flashing lights some warning of impending doom ?

cheers

anyweb

 

[anyweb]

ok it's hard to believe but...

well, after a week or so with this annoying flashing leds (flashing red/green at the same time for 30 seconds or so with each keypress on the fob, regardless of which key i used and regardless of whether i attempted to sync them or not) i went against my better judgement and bought new battery's for my 'spare' key (aka the second key which wasnt shining the red light at all on the key but was opening the doors and causing the above behaviour)

i locked my car. the lights flashed annoying at me., went into statoil, bought two new lithim batterys, shoved them in the fob, pressed it, and too my astonishment the green LED flashed normally, as did the RED led when i pressed the fob again...

so the moral of my story is it looks like we have to change the little lithium batterys in the fob once a year to avoid those nasty leds, seems odd to me as the other key (my main one) had the batteries replaced with new ones last year, and still flashes the IR light bright red when pressing the fob key and holding.... yet it too produced the RED/GREEN flashing on the mirror.

i'll replace the batteries in it tomorrow to see if it fixes it also,

just a fyi for ya all and for me too, in case i forget this time next year

cheers
anyweb

 

[Blobcat]

2 yrs is the recommended change, it is in the service manual if I remember correctly

 

[max200]

Can anyone please advise how I remove the old battery on my 3 button key fob, I dont want to ruin the fob by just trying to separate it.

 

[G MAN]

Car handbook should give procedure but if not, slide out the metal blade & use horizontally to press back the spring loaded clip in the cavity, whilst using a fingernail to prise the cap away from the top of the fob...hey presto!