2001 torque converter switch

hi. My cousin's got a 2001 4cyl auto. He ran a diagnostic on it and it told him that his torque converter switch needs to be replaced. I'm not familiar with that part. Can someone give me some info and tell me how hard it would be to replace? thanks

hi. My cousin's got a 2001 4cyl auto. He ran a diagnostic on it and it told him that his torque converter switch needs to be replaced. I'm not familiar with that part. Can someone give me some info and tell me how hard it would be to replace? thanks

Solenoid or switch?
What was the code no?
What is it doing or not doing?
3 or 4 speed auto and what engine?
MT