YetiHK

Trying to figure out why my KeylessGo is KeylessNotGo. Briefly:
- W220 facelift model (with KeylessGo keys instead of cards)
- KeylessGo has not worked in the time that I've had the car (about 8 months)
- keys coded correctly in STAR (tracks 6 and 7, both for EIS and KeylessGo)
- no error codes
- all KeylessGo actuators (doors, trunk, engine start) working as intended (checked on STAR)
- "key not recognised" message on dash when pressing KeylessGo actuators, but remotes on keys otherwise work (door lock/unlock and trunk)

I got a cheap spectrum analyser to see if I could learn more. It seems to work - there's a spike at 315mHz when I press the door unlock button, for example. But it cannot detect any activity from the antennas (supposed to be at 125kHz). On STAR, I used the antenna test function on each of the antennas in turn - supposed to activate the antenna for 15 seconds - but there was no activity on the spectrum analyzer at all near the activated antenna in every case.

Could the KeylessGo unit have failed without triggering any error codes? Or would it be possible to disable the antennas, perhaps as a theft prevention measure, without triggering any error codes? Any other possibilities I'm missing?

(I'm tempted to remove the KeylessGo control unit from the trunk to check if anything is unplugged, and trace the wires from the module to at least some of the antennas, but wanted to see if anyone has thoughts on this first, or suggestions of other things to check. I have had the trunk lining out before, and there were no obvious missing wires on the module - see photo).

wallyp

I have no personal experience in this area, so take this with a grain of salt...

I have a vague memory of a thread a couple of years ago on BenzWorld discussing that KeyLessGo would only work on the first few tracks, and not on the higher tracks. Perhaps a post on that forum would get an answer.