central locking key failures

[robbo1010]

Car--C220cdi 2001--mileage-70k.Both keys have an intermittant failure in that occasionally they do not open the c/l. My local MB "specialist" having done a diagnositic check via his Star system has replaced the ignition switch plus both rear and front Sam units.The cost is now £600+ with no sign of a solution.Any
suggestions I might put to him.

 

[V12]

If it works like the S Class then the Antenna Amplifier fails giving poor or no reception to the keys.

 

[robbo1010]

Thanks V12 I will suggest this to the Technician. But if this is the case surely the radio reception would be poor(which it isnt)

 

[Markanthony]

Here's a earlier thread with virtually the same problem
http://www.mbclub.co.uk/forums/electronics/91465-w210-key-fob-not-working.html

I still have this annoying issue and no official dealer is able to throw any light on it - someone out there must "know" the correct solution as this keyfob / iginition / C-L issue isn't uncommon.
My keys stop and start working at will/randomly/totally erratically, the fault manifests with no consistency so it's really hard to work out what's the matter - main dealers say they will "start" by changing keys and then take it from there but that'd incur huge costs - surely they must know what this issue is????
If you get a definite answer robbo1010 please remember to post it - Likewise
cheers
MA

 

[Dec]

Does this fault only happen when you unlock or does it also happen when you lock?

A bad remote button is always a possibility, every time you use the remote fob, shade the Red LED light on the remote from daylight and watch to see if the Red LED illuminates, it FAILS to lights up… then the central locking shouldn’t work.

Dec

 

[robbo1010]

Thanks Dec but the remotes have been thoroughly checked out and are transmitting as they should.

 

[robbo1010]

Thanks MA it seems its trail and error in replacing parts to see if one solves the problem.
My local man is a "MERCEDES SPECIALIST" who was a workshop manager at our local MB dealer and I have known and respected for a long time. Today we have agreed that a call to MB Technical might help but MB are loath to help out if your not a dealer.If we get a response I will post an update----Best of luck and regards ROBBO1010.

 

[Dec]

Did you try putting the remote within 2 mm of the door handle when unlocking, the IR locking is supposed to work if the RF signal stops working… you would have to do this every time you unlock to see if it ever fails with the remote up close to the door handle.

Dec

 

[robbo1010]

Tried that Dec and with both keys and nothing happens (so both keys today are inop on the c/l ) Usually what happens is I get in the car with the metal bit and when I stop and switch off, bugger me the c/l works with the remote!!!

 

[Dec]

When you get in with the metal key blade, because the remote doesn’t work, the alarm is still armed, because the alarm is still armed, the siren should sound when you open the door, does it?

There is one thing on these cars that can gives trouble and can give mystery faults when the car is about 10 year old, the alarm siren, it knows when you lock and when you unlock the car, it knows when the key is put in the ignition, when the boot is opened or shut, its ON all the time, whether the car is locked or unlocked.

As a long shot, you could try unplugging the alarm siren, it’s a no cost and a DIY option… you might get lucky.
Example of a faulty siren… Alarm / Siren Issues : Goes off for no reason/Kills Battery FIX DIY.. - MBWorld.org Forums

There is very little you can do now, the diagnostic technology seems to be of little use unless this intermittent fault is present when it’s hooked up to the diagnostics.


Dec

 

[robbo1010]

Thanks Dec
Will get my man to disconnect as you say and see if it works.
At this stage desperation is so rife i will try anything.
Any results will post for everyone to see.

Regards

Robbo

 

[CassleyAutocare]

I have heard of the rear screens failing, on some antenna is built into rear screen. Just something I have heard before

 

[dazzaf1]

I have exactly the same problem with my 2004 clk 270 cdi. And it's the antenna in the roof liner stuck to the black part of the glass on the back window. It tends to not work when cold and damp. But after a run or a dry day seems fine. So I just put up with it. For now.

 

[robbo1010]

Success!! New key plus rewired the radio direct and not via the ignition. All working fine.