I've bumped into tear down threads.

You need to refurbish the key cylinder or you will have a bad day. Do you have more than one key vs. Sometimes it's a worn key.

When my dad's Buick rendezvous had the same problem I had to disassemble the cylinder and pull out all the wafers so he could use the car until we got a replacement cylinder. I forgot if we got a matching key match or he ended up with two keys.

Look into official cylinder replacement so you can use the same key or a lock smith that can swap wafers to match a new cylinder to existing key.

It's not very difficult to rebuild/refurbish the door cylinder and I will take them apart completely to clean them if I have them out for some other reason. I don't know how to get the wafers to rekey but I could do if I can find the wafers say on eBay or Amazon. Especially easy if you have the old cylinder.

In a pinch I'd see if the door cylinder wafers could be used in the ignition cylinder if the key fob works to unlock.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)