The Mind Probe is also a jedi power in canon. Who is to say which one he was talking about? 😉 If someone can say that Luke transmitted his thoughts to Vader, instead of vader reading his mind, then i can say that the mind probe that he was talking about is also the established jedi Mind Probe 😉
And, if we are using wiki, this clears up that Vader was using the mind probe (thus reading Luke’;s mind) in ROTJ 😉
http://starwars.wikia.com/wiki/Mind_probe_(Force_power)