Key fault

[Finzky]

Spare key problem (which was sitting in the bag as spare one and was not used at all for couple of years) - it does lock and unlock the car, but I can't start the engine with it (changed battery`s to new ones - i tought fault is in batterys). There is that noise comming out from key port when you are inserting key - small buzz and you can turn egnition on - normally, but this key even don't make that buzzing noise at all. If this key wasn`t from my car I'm pretty sure it even won't lock/unlock doors.

I`ve been adviced - if you are not using key for some time period it can loose code to start engine and have to be re-programmed for around £250. Is this true or not? Is there any other way how to sort this out?

I don`t have problem with "main key" - it unlocks/locks the car and I`m able to switch engintion on. Only this key was used by previous owner on daily basis untill I bought the car.

Thanks in advance!

 

[wongl]

The ignition lock has a coil to energize the key and do not rely on the battery in the key. Sound like the coil in your spare car is faulty, which can be caused by dropping the key. You can try to get your spare key repaired.

 

[bob6600]

Open the key (plenty of vids on youtube) and see if the coil is damaged. A new one is less than £9 on ebay which is expensive but a lot cheaper than a key repair. If you can solder, you can probably fix this yourself

New Antenna Signal Coil for Mercedes 2-3 Button Smart Remote Key Repairs | eBay

 

[Finzky]

Thanks for advice. I took key fob apart and if be honest I can't see any obvious coil damage apart of bizarre color difference from blue to "normal copper color". Looking detailed inside winding looks for me a bit in disorder for 1/10 of mm as it should be on left hand side.

 

[bob6600]

I could not find fault with mine at first but then found the solder joint on one end had come off. I Soldered it back but no good so replaced the coil and all was well.

 

[tabbywrench]

If the above does not work google replacementmercedeskeys, £250 sounds alot

 

[zipdip]

Yes send the key to replacementmercedeskeys they are near Birmingham look on their site and give them a call £250 is way too much you could get a new key from MB for that.

 

[Finzky]

I'm taking my car tomorrow to do full filter&liquid service, I will ask there about the key, if not definitely will whisper to replacementmercedeskeys.