For quite a while my upshift button has not been reliable ,,sometimes it would not actuate a shift when pressed ,,which is not good when accelerating and you want the next gear..
Sometimes it would shift on the second or third try ,,but eventually was very unreliable.
Down shifting was always good.
I figured it was a problem with the up button , so I carefully levered it out with a small flat screw driver , and sprayed a small amount of WD40 onto the chip ,the wire connection and the button itself.
Fixed it ,,now it works perfectly every time..
Good ol' WD40 to the rescue again..
Hope this helps someone who may have the same problem.