A "converter clutch" is a part in a car's automatic transmission system that helps to improve fuel efficiency. It connects the engine to the transmission, allowing them to work together efficiently. Full definition
There could be a problem with the torque converter clutch staying on while the transmission is shifting into overdrive. (yourmechanic.com)
If I have any additional problems with that torque converter clutch code, I'll do that probe test. (mechanics.stackexchange.com)
Road test the vehicle and monitor TCC % solenoid command state — duty cycle and TC SLIP ACT torque converter clutch slippage — rpm, while in 2nd, 3rd or 4th gear with a TCC % reading 0. (autoserviceprofessional.com)