As far as I can tell, some of the earlier bikes had the option for no iABS (Generation 1) where the wheel speed sensor was wired directly into the ZFE control module. I’m not sure whether they used one of ABS sensors for this or they provided a dedicated Speed sensor. Others more knowledgeable may know. I’m also not sure whether it was front or rear wheel driven either.
Have a look at your ZFE control module, and pins 13 and 51 should be empty. As these are the pins for the speed sensor if or when fitted. Sorry about the quality of the picture. The Hanes manual for your bike might be clearer.
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