Hi, new to the forum. i know this topic has been discussed many times but i can't seem to find the answer to my problem. i have a 07 c230 sport and a few months ago my wife drove the car through a pretty deep puddle and almost flooded out the car. later that night the alarm would randomly go off. i had to leave the key in the ignition to keep the alarm from going off all night. i left the hood open and let the car air dry out and the problem stopped. a few days later the key fob stopped unlocking/locking the car but it still will turn the car on and the lock and unlock button on the dash will work. i tried changing the batteries and that didn't help. i tried new fuses as well but that didn't help either. im thinking my wife messed up something in the central locking system but im not sure because the car will still lock with the button in the car. any ideas? any help is much appreciated. thanks.

p.s.
i don't have a Mercedes dealership close to where we live and we lost the other key fob so we are down to one.

I'd try to find someone who can test if the key sends RF signal. If it does, maybe it's the antenna in the rear window/wiring/etc.

Not sure what controls the remote unlock, but check your front SAM for corrosion on the pcb.

I just used my phone camera to test the rf signal on the remote and got nothing. Seems like it's a bad remote. I'm guessing calling a dealer is probably the safest thing to do.

That would be infra-red signal though.
Hmm, probably reasonable to assume that if IR does not work then radio wouldn't too.

Maybe corrosion inside the key's circuit board? See if you can take it out and check.
(Youtube has some videos on how to "change mercedes key shell")

Ah yes ir lol that's what I meant...long night. Thank you. I will check out some videos and see what I can come up with.

Pulled the board from the shell and there is corrosion at the end where the panic button is. What should I use to clean it off? You are spot on with this I really appreciate the help.

Rubbing alcohol 90+% I'd say. Amazing that it's still able to handshake with the ignition.
Be super careful about cleaning it though, since it's the only key...
A replacement key can only be purchased at the dealer for $270-300

Holy smokes lol. Well I showed my wife the corrosion on the board and she says "oh maybe that happened when I dropped it in my soda that one time". I'm already flirting with disaster so I might as well get a new key and hope this one doesn't die in the mean time. Or my wife tries to kill my car again. Bad thing is the closest dealership is 3 hours away. Thanks again for the help. Much appreciated.

Wow, soda lol
She sure does take care of that key
Yes, probably the right thing to get a new one.

I am 1:40 from the nearest dealer so kind of feel your pain.
Try to call them and arrange the order, they will want to look at your title etc.
The key is supposed to be sent from Germany, ready to rock, so don't fall for "programming it to the car" BS. Maybe they even can overnight it to you once they got it?
If they want too much, it may pay to shop around.

Keep us posted on the fate of the old key though

PS: you could buy a chrome key with a round panic button off ebay for $20 and have someone with good soldering skills move the eeprom chips from the old key to the new one - cheaper than buying from the dealer

I would think that they would require him to pick it up in person at the dealership to sign the paperwork, unfortunately.

OP - make sure you know exactly all you need to give them. Registration, your license, etc. Since you're 3 hours away, it'd really suck to not have all of the information with you; they're sticklers.

Wow sounds like getting a new key is going to be a pain in the butt. Thanks for the advice. I'm probably going to call a few dealerships tomorrow and see what I can do. Im also going to see about getting a new case and cleaning off the old key and see what happens lol. I know a guy that's pretty good with a soldering gun.

I am having the same exact issue with my 07 230 sport! But have no idea on how my key could have gotten wet. When the key fob buttons are pressed the red LED lights are not working. I honestly think it's the fob since I don't drive through massive puddles : ) . I would take the fob apart but I'm currently in a parking lot on my cell. I'll do it in about an hour when I get home so I don't have to pay for a tow truck if something goes south.

Tell me why I just circled the block, parked, removed the key and immediately pressed the unlock key and it works now?

Because MB electronics.

It's about to fail - sounds like an intermittent connection

mine did the same thing the first few days. it would work one day then not work at all for a few more days, then back to normal. then one day nothing...haven't heard from the key fob since

ender006


can you still start your car? does the alarm still continue to sound at all hours of the night?


I will be going out of town this weekend and don't want to get stranded of have problems with valet


my key cost here is $240 out the door and wont be here till Monday.

Yes I can still start the car. And I haven't heard the alarm since the key fob went out. But I also haven't been able to arm the alarm since the key went out as well. I'm not sure the alarm even still works anymore lol. Guess I will have to tackle that problem after I get a new key.

last night my car cried like a FN new born. I never armed the car it just kept going off for no reason.
when I ran outside to stick the key in, I always started the car and pressed the unlock button on the fob a couple times and it would re-program(I guess you could say).


guess ill stay here till the key does come in.

but tell me this isn't strange.. last night I met up with a girl I know who drives a lexus. I parked next to her, put the keys in my pocket and hopped in her car. as I sat down, her car beeped, I looked on her message center and there it read "key not detected". that was the first time she said she has seen that message..


either her keys are dying or my key is spreading some kind of sick virus on other cars. lol

Well a bit of an update. Not a good one. I've been using the cut key to unlock the drivers side door until i get around to getting a new key fob. I'm at work right now and was going to run out and grab a bite to eat. Well the key turns the lock but doesn't unlock the door. So I'm officially locked out of my car.

Sucks.
Looks like you may need to call one of those lock-out companies.
They can pry the door and pull the lock knob from what I gather. Not sure if it works on Mercedes.

that night I removed the passenger tire, and the fender well. I took the siren out and shook it. it was a little wet. it looks like there are some drain hoses running right next to them. (I has been raining a lot here). I left the siren under a heat lamp for a while and reinstalled it. no problem since.


also my fob wasn't working.. I started the car with it.. drove it around the block, parked it, turned it off, and before removing the key from the ignition I pressed the unlock button a couple times until I saw the red light on the fob work.


that has worked and it has not came "un-programed"


hope this help future MBworld users