> A consequence of this is that the original keyfob gets out of sync, and will no longer function.

I always wonder about this: what is the consequence of that? Can the user reset it, or does it have to be done by a retailer or something?

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brk 6 days ago | parent [-]

Depends on the implementation. Most times you just have to click it a few times in a row. The receiver then realizes it missed a few button presses and it re-syncs. I’m not sure what that window is though, at some point it might get so out of sync that the receiver ignores it and assumes it is a wrong fob.

	▲	siffin 6 days ago \| parent [-]
		If I remember correctly the size of the rolling window differs, more modern vehicles may allow about 100 code discrepancy before ignoring the transmitter, while old models might have been 5 to 10.