City have accepted an undisclosed fee for the striker who made 88 appearances for the Sky Blues scoring on twenty nine occasions.
John was signed for £250,000 from Birmingham City and had reached the point in his contract where he was allowed to talks to other clubs.
"I'd like to thank Stern for his services over the last couple of years with Coventry City," said Heath to the club website. "He is out of contract with Coventry in the summer and he felt this was too good an opportunity to turn down."
Sunderland boss Roy Keane told his club website: "We've agreed a fee over the weekend with Coventry in terms of bringing Stern in and we're looking to
finalise that. "He's a powerful lad and sometimes we've lacked an
aerial threat, especially since Chris Brown left. We hope
Stern will play a part in help us get promotion."
The Trinidadian will link up with fellow countrymen Dwight Yorke and Carlos Edwards. He will be available for Sunderland's game against Palace tomorrow but not against the Sky Blues on Saturday.