BruNo

hi!

my (w203) C240s keyless entry only works when i directly point my key (very near) onto the infrared window on the driver's door handle, otherwise, it is impossible to lock/unlock the car from any point. the batteries on my keys are okay. the keys also start the engine fine. it seems only the infrared system works and not the radio frequency for the keyless entry. thanks.

David N.

What model year is your car? Some '01 models had problems with keys. Are you sure the batteries are OK? Have you put brand new ones in to make sure?

If you can't find a resolution to the problem, go to your dealer. They can order new keys for you.

MarkL

I agree with David. It's very easy to replace the batteries, so you might want to try that. The key on my 2002 C240 was having problems -- I replaced the batteries and have not had a problem since. Also, is the red LED lighting when you press the lock/unlock buttons on the key? Mine was working intermittently.

Also, had the key been working correctly before? If so, and now it has a problem, I think that would also point to a battery problem.

MB-BOB

Your car was delivered with two Smart Keys... I'd try the second Smart Key first to see if you still have the problems. If the second key works, then swap batteries from second to first to see if that fixed key #1. If so, then maybe it's a battery problem. If not then maybe Key#1 is bad. Put batteries back in each unit where they started and use key #2 until you can take both back to dealer for free key upgrade.

I had a single day about 3-weeks ago where my Smart Key would lock but not unlock. The check LED worked sporadically. I took the batteries out and put them back in, then everything has worked fine since. The metal clips that hold the batteries in place are not really aggressive in making good contact with the batteries.

BruNo

thanks for replying guys!

Well both keys do not work. Both of their check LEDs blink when i press the buttons. I can only lock/unlock using the IR on the drivers door handle. My car is year 2000 production, its brandnew, but i did not have d chance to check it coz i just had it shipped to me, i live in a far place. Could it really be the keys??? or do i have to replace some component/module in the car???

btw, when the car arrived to me, the keyless entry has been like this!!! aarrgghh..

wizkid

We had to get two new smart keys for our 2002 C240. They would not work half the time. It was supposedly causing the sun roof not to work, the trunk not to open and the windows not to roll down automaticaly using the one push feature (all of those things were happening using the buttons in the car).

Very weird!!

Replaced the keys, and everything is working again.

So far, I consider this MB car to be more trouble than my 99 Camaro Z28. I hope our luck gets better.

Eric

SoCal240/6

the keys for these cars are all screwed up.

my key acted like yours, then eventually died. even when it worked, it would only do some of the functions (like it would not roll up the windows all the time).

went to the spare key, it eventually died, too.

there was some kind of recall. the dealer replaced both keys for free and they work great now.

c240x

Ever try to put the key under you chin, and depressing one of the buttons? Apparently you head will act as an antenae and the range is greatly improved. I tried in once in a parking lot and it actually works!

freakinfreak

Are your windows tinted? That was the root of my problem. After I had my tint removed, I have no problems w/ the keyless entry range.

SoCal240/6

isn't the sensor (at least on the sedans, don't know about the coupe) that little square thing on the front door handles?!? If so, how would tinted windows affect it?

young

no, no. this only works if you stretch out your arms like a satellite dish and then point w/ your index fingers towards the sensor.

mbtech208

c240x isn't joking. I have heard of people aiming the remote into their mouth to lock/unlock thier doors. It works, but people look at you weird.

freakinfreak

From my understanding, there is another sensor. My tint happened to be causing problems with the other sensor.

bagwell

just keep it unlocked to let the beautiful filipina girls into your car!!

seriously, take it to the dealer(if there is one there) or call Mercedes.

Fuzzo

I had a similar problem where my spare key stopped working. I took it to the dealer and they replaced both keys for me. Now they seem to be working fine and I do have a tint. I didn't have the tint when I first had the key issue.

I would definitely take it to the dealer and see what they have to say .... because my key works from a good distance away.. atleast for the locking and unlocking. to open the trunk etc, i have to be pretty close.

good luck

benzcollie

I have having problems with the keyless go system in my wife's CLK320. Neither key works except when inserted in the keyslot to start the car. Both sets of batteries have been replaced with no change. I've checked the fuse on a DVM and it checks good. Any advice would be greatly appreciated! I'll try disconnecting the main battery but don't hold out much hope.
Thanks

tommy

You should post this in the CLK forum. I don't know how many people with W203 c classes would have Keyless Go as an option, and be able to help you.

benzcollie

Thanks Tommy, I'm new to this.

JDM_love

I had the exact same problem with my remote. I replaced the batteries with new ones several times but didn't solve the problem. I had another spare key that had a beaten up body so i removed the chip from the spare key and replaced it into the better condition key and re-inserted the battery and my problem was solved. The chip is the problem.

cmh1991

I'm having the same problem in my 2003 C240. I just had my car retinted yesterday with the same percentage tint and now the key does not work unless I am right next to the driver's door pointing the key at the infrared sensor. I replaced both batteries thinking that was the problem. Does anyone have any advice?

Moviela

CMH, your tint installer has broken the connection between the antenna amplifier and the rear window grid. They might have broken a trace on the window when removing the old tint. This happens frequently.

sgagnon

Does anyone have a picture of the window grid and the antena amp wire to tell if its broken. I just got my 04 C240 tinted yesterday and now I have no keyless entry. I changed the batteries in the remote and nothing. I have to use the actual key to get in. Could it be a fuse thats blow? Any help on this would be great appreciated.

Kotat90

I know this about 1 years ago, but Im hoping you or anybody can help me out. Two days ago, I got the clear tints on my 04 C240 removed, and had dark charcoal tints placed on them. All 4 doors, my back window, and also 3 inches of my windshield. I was able to use the keyless entering to drive my vehicle the same day. But on the next day, my smart key stopped working. i changed the battery and everything and it still doesn't work. Unfortunately for me, my manual key doesn't turn when i put it in the key hole, so now I'm pretty much locked out my car. Anything suggestions on what to do or what caused it? I'm thinking about getting a spare key from the dealership and trying to find out why my manual key doesn't work. Help please?