Key stopped working

[such01]

My key decided to play up today - opened car ok but no ignition or lights on dash - completely dead.
Radio worked.
Tried the spare key and it worked fine. The lock button on this key is a bit temperamental - hence why it's the spare.
The main key was repaired a while ago due the locking button not working properly too.
Is it time for a new key or can it be repaired?
thanks

 

[Continental]

My key decided to play up today - opened car ok but no ignition or lights on dash - completely dead.
Radio worked.
Tried the spare key and it worked fine. The lock button on this key is a bit temperamental - hence why it's the spare.
The main key was repaired a while ago due the locking button not working properly too.
Is it time for a new key or can it be repaired?
thanks

Probably no harm in opening it up, as if to replace battery (probably replace battery too just in case) and spray a decent amount of electrical contact spray around keep an eye out for any obvious grime/oil residue that may need to be carefully removed … did this once to a key that was behaving in a temperamental way and it solved the issue for me.

 

[such01]

Probably no harm in opening it up, as if to replace battery (probably replace battery too just in case) and spray a decent amount of electrical contact spray around keep an eye out for any obvious grime/oil residue that may need to be carefully removed … did this once to a key that was behaving in a temperamental way and it solved the issue for me.

had a new Mercedes battery fitted - how do you open it up? Never mind opened

 

[such01]

no joy - was very clean in there already. Looks like new key is required.
Where's the best place to get from or is it only from dealers?

 

[OneForTheRoad]

no joy - was very clean in there already. Looks like new key is required.
Where's the best place to get from or is it only from dealers?

If it's pre 2015 you can have 1 made by a locksmith £100 to £150, after 2015 it's dealer only . £300.

 

[such01]

If it's pre 2015 you can have 1 made by a locksmith £100 to £150, after 2015 it's dealer only . £300.

Great before 2015...

 

[such01]

Actually, I have breakdown repair cover up to £565 with the AA, not sure if it covers faulty keys but it covers all electrical parts with some exclusions.
I have to get them out to check which is a right pain and a waste of time, but if the key is covered it will only cost my excess of £35.

 

[such01]

Well guess what? - the key is has started to work again before the AA arrive - I wonder what the problem is/was and if it would occur again leaving me stranded?

 

[such01]

Had keys checked today and both are fully functional - the chap also said the EIS is ok so could be the steering lock.
I have noticed the steering lock does not engage anymore - must have been like this for some time now.

 

[drosser]

Had keys checked today and both are fully functional - the chap also said the EIS is ok so could be the steering lock.
I have noticed the steering lock does not engage anymore - must have been like this for some time now.

Hi guys, I'm a newbie Mercedes owner with a key problem. I bought a 2012 w212 e220 CD1 estate from a local hotel (used as a concierge car) - actually there were two identical cars for sale and my friend bought the other one. There was only one key with each vehicle - the hotel were unable to locate the second keys at the time of sale. My son works there and brought home the second keys a couple of days ago - they had turned up in a cupboard. Suggestion was that they had not been used for a long time so the batteries may be weak / dead. On pressing the lock / unlock buttons, the red light flashed but the keys would not perform in either car. I replaced the battery in each - again the red lights appeared but neither car would lock / unlock / turn on ignition. I googled the problem and found this site Mercedes Key Fob Not Working – MB Medic . I followed the resync instructions carefully with each key to no avail. There was no point checking the fuse or the AAM unit as the original key works perfectly in both. Another anomaly is the comment re the infra red signal check with a phone camera. All 4 keys show a signal light on the lock and unlock button depression - none of them show either a light on the key or a light on the phone when the boot / trunk button is depressed - however, the tailgate unlocks and self raises on both vehicles with the original keys supplied so it is not a fault. Apologies for the 'long-winded' description but I felt that all the facts should be included. Does anyone on the forum have a working knowledge of the key system and, hopefully, a way for synchronising keys for this particular model. I have an Autel diagnostic unit which claims to synchronise keys but I have never tried that function and fear that I could make things worse.