It is my understanding that the shift delay is activated by vacuum in the line that goes to the right hand side of the transmission (passenger side in the US). Some parts vendors refer to this as the kick down cable assembly. I am not sure how it functions but it somehow overrides the throttle position input from this cable. I also believe that if this line will not hold vacuum then the only consequence is that there will not be any shift delay.

I would love to get some confirmation or correction on my understanding.