Should work by the looks of it. So long as it contacts both the pins it is wrapped around properly, it will work fine. Pin 2 ties to pin 20, at least in all the images I've seen. Presumably the factory fitted cap connects pin 17 to either pin or pin 20 (not sure which) but it doesn't matter - the suggestion is that a jumper from pin 2 to pin 20 will allow for full ODB access on the 16-pin connector (when the 20-pin cap is in place).

Not sure this wil sort your emission testing issues but as I said, what's to loose?

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Wayne
2005 BMW X5 3.0d (b 02/05)
2001 BMW F650GS Dakar (b 06/01)