It's a feature I like too.
The two versions (V6 and diesel) are quite different, but they do both use the signal from the ABS (Antilock Braking System)
, though in a different way. As far as I know, the diesel get's it speed signal over CAN (Bus Controller Area Network)
so intercepting it isn't a question of a pulse but A CAN
node. I'm not sure about the V6, I'd have to check.
On the diesel, the cruise is built into the engine control module, and there's an interface unit. On the V6 it has a separate unit that drives the pump system, and again another interface unit.
In both cases the set speed is controlled by software, and short of trying to rewrite that software I'm not sure how it would be achieved. I suppose you could
intercept the speed signal to make the cruise system think it's travelling at a different speed than it is, but to be honest I'd be worried about what happened if there was a glicth with the system. Wouldn't want a Toyota would we?