Does your W124 key look like a W123 key or like the double cut W126 key? Doing a quick search it looks like the W124s use different keys then either?

My local VW dealer can cut steel keys. I would assume a good locksmith can too, as long as they're the kind that are cut, not milled. I've not found any non-dealer who can cut keys that are milled. VW wants $90 for one for my 99 Jetta

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.