05 Toyota Matrix w/OBD2 Fault Code P2770. Tranny rebuilt, now what?

Question

I have a 2005 Toyota Matrix with 105,000 miles on it. Got check engine light, and code p2770 "Torque Converter Clutch Solenoid Circuit High". Took to a transmission shop, and got a new torque converter, new solenoid, and new internal wiring harness. This along with full rebuild of the transmission. After a few weeks the problem came back, same code. The shop suggests the problem is the ECM. The ECM was replaced 3 years ago as part of a recall. I am $2750 into this and no closer to a solution. What next?