Twice in the past 2 weeks I've had throttle position sensor codes on a 2002 CLK320 MBZ as well as a 2012 ford pickup.
These engines are 'drive by wire' meaning the computer is in command of the throttle based on your foots position~~ idle, cruise, floored etc.
When this sensor fails or winks out the computer is not sure where to go or what to do, so to prevent a situation like the runaway Toyota it simply puts the engine at idle. So you are pretty much stopped.
No more throttle cable. All electronic now.