I was going to start a new thread, until I came across this old one through a Google search.
Someone asked me the other day about the electronic steering on my tuck, and what the steering wheel was physically connected to - if anything.
I'm embarrassed to say I didn't know the answer.
As someone who has always worked on their own vehicles, it feels strange that I haven't spent time turning wrenches on this one.
I guess with the truck being newer and under warranty all this time, I've had no real reason to spend a lot of time under the hood.
Anyway, I found some great info in an online car review (and a helpful diagram in this thread) that I thought I'd share in case anyone else out there is fuzzy on how the whole thing works.
An EPS steering rack (gear) is basically a standard rack-and-pinion, only now powered by an integral electric motor. The steering sensor mounted at the rack detects driver input at the steering wheel, while the EPS control module uses this and other data such as vehicle speed to tailor fit the amount of steering assist. This provides advanced control that wasn't possible with hydraulic power assist, to adapt steering and handing to driving conditions. I've seen very few problems with the systems currently on the road, and the discontinuation of the hydraulic power source eliminates the inevitable noise and leaks. Plus the EPS system involves less bulk and weight.
