w204 key packed up

[sceh]

All of a sudden my key doesn't work. I changed the battery and tried 3 different ones but it still doesn^t work. If I get close to the car and press a few times, it sometimes works so I initially thought it was the battery. When I press it there is no red light so I suspect the contacts inside are dirty.
Is this a normal occurrence and is it possible to open the key beyond the battery compartment to clean the contacts or is it simply dead?

thanks

 

[Dave.tam]

Sometimes the contacts for the front and rear of the battery open up slightly. Try taking the battery out of the key, pressing the contact down so it's nearer the base, and then sliding the battery back in.

 

[whitenemesis]

Try unlocking whilst holding the fob a couple of inches from the driver's door handle. Maybe just the RF signal is down and the IR will work?

Otherwise try these guys for a key repair

Mercedes key specialists- Need new Mercedes keys? Replacementmercedeskeys.co.uk

 

[sceh]

Indeed it works when I hold it close to the driver side handle but not remotely. This means the RF does not work I suppose. I didn't even know it had IR as well as RF!
If the RF is gone can I rely on the IR or is it the same chip?
thanks

 

[whitenemesis]

It could be the car side of the system, the antenna or amplifier is failing.

Get the codes read on STAR as a starter..

 

[190]

I recall reading about a common fault being a coil soldered to the key fob circuit board. For anyone handy with a soldering iron it would be a cheap fix as new coils are available for a few pounds on ebay.

If you are not handy with a soldering iron then professional replacement of the coil shouldn't cost too much.

 

[whitenemesis]

I thought the coil was to do with the immobiliser or IGN not the remote locking?

 

[sceh]

I thought one keyfob was broken and the other not but it turns out they both behave the same - IR works but RF doesn't
The car is a w204. What are the next steps to check since it seems to be the car side. Both fobs have new batteries an light up ok.
thanks

 

[pcctech]

try pointing the fob pressed on into a mobile phone on camera should show a red light on the phone picture if transmitting , this will confirm if sending a signal

 

[whitenemesis]

I thought one keyfob was broken and the other not but it turns out they both behave the same - IR works but RF doesn't
The car is a w204. What are the next steps to check since it seems to be the car side. Both fobs have new batteries an light up ok.
thanks

As said above, get the codes read using STAR.

 

[sceh]

Now here is a curious thing. Both keys now work perfectly! Oddly, when the keys didn't work, the remote control for the garage didn't work either - new batteries too. ll of a sudden all works fine.
Explain that if you can. I went to the dealer and he conformed neither fob worked.

 

[Codger49]

Can't explain the dealer finding the fobs didn't work, but maybe your problems with the fobs and your garage remote were down to some sort of radio interference?

 

[sceh]

I also thought that could be the case and perhaps sunspots or flares could be the cause but February has been quieter than normal. Had it been OK at the garage but not at home (10kms away) then it would make some sense. Also had it just been the car and not the garage remote too.
Very odd.

 

[Dec]

Is the car alarm working?

What year is the car?

Dec

 

[sceh]

2011