The gist of Professor Gilbert's testimony to the House Oversight Committee is that Toyota's electronic throttle sensing system is poor, in that the redundant signals are insufficiently different from one another, so that the diagnostic system can be fooled into thinking that a short circuit between them is a driver request for wide-open throttle, and not a fault state. He also just testified that other automakers would catch the fault that he induced "right away".
"If I would have done that on a Buick or a Honda... it would have set a DTC or code".