2008 Tundra P0117 - ECT Circuit Low

I Have a 5.7L V8 that triggers the C.E.L every 30 days or less with code P0117 fault every time. I have replaced the ECT 5 times and fixes the problem right away then it returns. I have flushed the cooling system, the level is good, checked wiring for open or shorts- none, replaced thermostat and water pump, checked ECT connections..... the only diagnostic item left is replace the ECM.
I am curious if there is a spike on the ECT voltage from the ECM that causes this failure?? Any leads or tips??