2001 Cadillac Deville tcc stuck open code

I believe you would be referring to p0741 TCC stuck off. This usually sets when the slip speed is high when TCC is applied. It is not just an on/off system, it is what is referred to as pulse width modulated, or variable. Often times there is leakage in the hydraulic circuit. The chosen repair is to replace the converter, tcc pwm solenoid, and all of the seals in the hydraulic circuit. There are two seals in the case cover, one on the drive sprocket, and the turbine shaft o-ring.

First of all, what is the code, is it a p0741? To make sure the light stays off, you need to do a complete repair. The lower valve body has no pertinence to the TCC circuit on this trans, it is all in the upper valve body. You are going to be in pretty deep to just do a solenoid. If it is a 741, high slip speed has been seen at one point or another, I would not remove the trans without completely resealing the hydraulic circuit and replacing the torque converter, especially since you are over 100k miles.