My 2012 Camry's tranny has had the converter replaced. It started chugging again randomly. I serviced the tranny and put an anti shudder additive in. After 200 miles the check engine light came on and the code is P2770. But now the shuddering has completely stopped. Shifts perfectly and still gets great MPG. This made my traction control light come on also . What shall I do ?

 

This is a torque converter code:
P2770 OBD-II:
Torque Converter Clutch Circuit High
The Torque Converter Lockup Clutch creates a solid connection between the engine an transmission. When the Transmission Control Module (TCM) detects failure of the proper operation of the torque converter clutch, it will set code P2770.
Honestly, I think the additive is causing the code. A lot of these additives are thicker and more viscous than factory fluid, hence more resistance and pressure. This may cause the codes to trip.
Your Camry sounds like it is suffering from the dreaded torque converter shudder that eventually ends up being a tranny rebuild or new tranny.
My unofficial advice is drive her and start saving some pennies for a new tranny/rebuild. You say it shifts great now, so take it one day at a time. Just know that there is an end life situation going on here.