The idea that the light is on and there are no codes leads me to think it is an issue with the OD switch on the shifter handle. The control switch indicator light illuminates only when the overdrive switch is turned to the off position, or when illuminated by the transmission control module.
So, what happens when you toggle the switch? Also, you indicated no codes. Did you scan the can bus?
CAN stands for controller area network. Basically, the different modules are tied together via a few wires. This type of scan will retrieve codes regardless of the module storing them. I ask because most scanners can't read other codes.
Here is a link that explains how it's done:
Let me know as much as you can. Also, let me know if you have other questions.
Friday, November 25th, 2022 AT 8:16 PM