2006 Buick Rainier brakes failed

About a month ago my Wife was driving and the brakes failed in the driveway. The pedal completely locked in place and would not move. The vehicle continued to roll forward at idle and my wife had to steer it into a tree to get it to stop. She did not think of trying the emergency brake but had only seconds to decide what to do. A neighbor saw this event and says the brake lights came on, the vehicle did not stop, and then the lights flickered and went out. My insurance company had my mechanic run a diagnostic after it was repaired (the body damage) and a DTC code showed up DTC 0244 or P1689. This is Traction control Delivered Torque Output circuit. Whatever that is. My question is what exactly is this malfunction and could it cause the brake failure and how? No one seems to able to tell me anything. GM did send a independent investigator out to look over the vehicle but I have not heard from them yet. The dealer could find no fault code or problem. Any light you can shed on this would be greatly appreciated and I will certainly make a donation.