first things first. have the valve body serviced and all the valves and their bores checked. The stroking valve for the TCC can jam up and cause this.
The bigger failure that causes this is a worn pump bushing on the transmission, oil pressure discharges from that wear and the TCC doesnt fully lock causing similar issues, on really bad leaks - you get other errors too.
I have also seen this failure from using wrong ATF - but it was a really trash quality ATF which I dosed with additive to fix - but I dont think so thats your issue.
and to the point of the check light not glowing - it can be easily cheked by commanding it on, or simply unplugging something like the maf or VVT - the check light will remain stuck on. Your code is showing as "pending" and pending codes dont illuminate the check light in toyota - that "lektrishann" needs to go back to school.
specially transmission speed monitoring codes which are intermittent.
