this came to my attention today in a stupid and annoying way my wife and I stopped for breakfast I forgot I had my key in my jacket pocket and tossed it in the trunk only to find out we were now locked out of the car my GLC300 would never have allowed the doors to be locked with a keyfob in the car I had to call someone to go to my house and retrieve the extra keyfob. Anyway I did discover the keyfob in the trunk will only lock/unlock doors by pressing the buttons on the fob the one touch on the door handles don't work with this fob is it defective or is there a way to reprogram or reset it I just put fresh batteries in it.

Ed

 

First of all, does your car have the KeylessGo option? If so, you'll have a Start/Stop button on the gearshift and black buttons on the outside door handles. If not, then this is why you were able to lock the key in the trunk and the doors don't unlock unless you press the buttons on the fob. If you do have KeylssGo, then either your key is not working (do you have a spare to try?) or you have a problem with the antennas not seeing the key.

 

yes I have the keyless go and yes the second fob works as it should I am able to open the doors and trunk with the fob in my pocket.. As an experiment I was also able to lock the second fob in the trunk.

 

That sounds like an antenna issue. Or maybe a KeylessGo control module problem. Start by checking fuse 58 on the rear panel. If it's good, then you're going to need to pull codes from the KG module. SDS is going to be the best bet for diagnosing that as it has the ability to read the signals form each antenna. I am not sure if the other tools (iCarsoft, Autel) can do that.

 

thank you!