Originally Posted by
ala_xfire
Agreed, that's why I mentioned the conductor plate, but the OP's is a 6 speed.
( I have no idea where the speed is measured in a 6 speed XF )
I'm searching the manual now. I have scanned the entire manual transmission section and there is no mention of a speed sensor. I suspect that the powertrain control module takes its information from the wheel sensors, I honestly believe that it's a matter of bad connection somewhere in one of the related components and possibly the fix could be as simple as disconnecting and reconnecting the major controlling electronic components, after disconnecting the battery ground cable first of course.