2004 Sorento overdrive light flashing....help

I filled up my 2004 Sorento with gasoline and added two fuel treatments, I went to the beach and then returned home but on the way home the check engine light came on and then went off but a few minutes later the overdrive light started flashing and hasn't stopped. I was told this could be a transmission problem but I'm not sure since it has only happened since using the fuel treatments.....