I had my 2007 Avalanche in to the get front brakes and the driver side bearing hub changed. 3 days later the traction control activated suddenly and forced it into engine power lessened mode(engine retarder). Is this a faulty bearing?

 

Could very well be. Connect to scanner and see whats going on. My experience with Cheaper made bearings is this exact problem. Not saying that's your problem but sounds logical since it started just after bearing replacement.