The West Midlands outfit squandered a two-goal lead to draw 2-2 at promotion-chasing Sheffield United on Saturday, despite playing against 10 men for much of the game following Jose Baxter's dismissal.
Pressley signed a new contract back in September, but just over five months later the former Scotland defender has left the club following a run of one win in 11 League One matches.
Coventry chief executive Steve Waggott told the club's official website: "This has been a very difficult decision from a personal and professional point of view, and we would like to place on record our thanks to Steven for his efforts over the last two years.
"But results over recent weeks and months, and our precarious position in the league table, means that a change of direction at first team level is needed.
"Neil MacFarlane and Dave Hockaday have been placed in temporary charge."
Coventry face a difficult clash with high-flying MK Dons at the Ricoh Arena on Saturday.
