the car is diesgned to protect it self (not shifting into reverse over 10 mph or so) the problem with toyota ISNT A ELECTRICAL issue its a diesgn issue. i have heard from sever credible people in the industry as to the problem...
toyota only uses 1 potentiomiter( the piece the gas pedel attaches to, that converts the motion of your foot to a electrical signal) everyone else uses 2 and a way to conferm the signal. if these signals dont match, the car go into a safe mode (no full thottle, 2nd gear limit)
toyota also does not have a brake interlock switch, where you step on the brake, the car goes into a idle state.
theres just a bunch of things toyota did to cut costs and its biteing them in the a$$ big time