Honduran Ramon Nunez grabbed a crucial equaliser for Scunthorpe at Coventry, but the Iron remain three points adrift of safety in the Championship.
The Sky Blues, themselves comfortably clear of the drop zone, took a fifth-minute lead when Marlon King smashed home from inside the penalty area.
Scunthorpe levelled before the break, the impressive Nunez having a shot deflected in from the edge of the box.
Chris Dagnall and Michael Collins went close while King struck over the bar.
The result leaves Scunthorpe still three points behind 21st-placed Crystal Palace - who drew 0-0 at Doncaster - with only three games left in the season.
Desperately needing the victory to boost their survival hopes, the visitors got off to the worst possible start when King played a one-two with David Bell and hammered past Joe Murphy.
It should have been 2-0 when Bell again crossed from the right, but Lukas Jutkiewicz could only prod the ball wide with the goal at his mercy.
Bobby Grant shot tamely at Keiren Westwood as the Iron threatened, and after King fired over for Coventry the away side got their equaliser, Nunez breaking forward and seeing his shot hit Martin Cranie and wrong-foot Westwood.
Scunthorpe could have gone ahead soon after when Chris Dagnall's shot across goal flew inches wide, before Michael Collins fired wide when Nunez robbed Carl Baker.
Both teams had chances after the break with King blazing over and Freddy Eastwood failing to connect inside the box as Coventry pushed for a winner.