Coventry have sacked manager Thorn and placed Richard Shaw and Carsley in temporary charge of the club.
Chief executive Tim Fisher told the club's official website: "We have not taken this decision lightly. We recognised that last season there were off-the-field matters that affected team affairs and felt it was right and proper to give Andy the chance to put that right over the course of the summer and the start of the season.
"We do not feel that has happened. Of course, the fact that we have surrendered the lead in the first three league games has not helped, but there are several other factors in this decision - not just three disappointing results."