Aftermarket OBD tools

I figured most of that out myself in the other thread, at low speed and small displacements there isn't enough self centring action from the front wheels to wind the EPS motor backwards through the reduction gearing, so the EPS "helps" the front wheels by powering back to centre when you let go of the steering wheel. Possibly all EPS systems do this, but you notice with the Jimny as there is so much slop in the steering that there has to be a large dead band built in, a steering rack always goes back to the same place.

If you actually want  to apply a touch of lock to overcome the camber, you hold the wheel and the torque sensor kicks in and maintains the displacement by reducing the torque to near zero until you let go of the steering wheel.

I still prefer the old hydraulic system tbh....

I assume that all this is to enable the safety features like lane departure, it all seems very unnecessarily complicated and probably quite expensive to to fix?

It's probably just to work around the inherent slop in recirculating ball steering.  Not many cars try to mix electric PAS and a steering box.  Presumably because of the resistance from the motor, there is no slop in my gen 4 steering.  A gen 3 can have something like 2" of free play at the rim.

Lambert wrote:

I assume that all this is to enable the safety features like lane departure, it all seems very unnecessarily complicated and probably quite expensive to to fix?

I think it sounds more complicated than it really is.  An electric motor for power assist is arguably simpler than a hydraulic system, and the only extra complication is the torque sensor on the steering column.  (The steering angle sensor would already be there, for the ABS.)  I tend to agree with Facade that hydraulic PS is superior, but even so, I wouldn't characterise the electric system as excessively complicated or expensive.  From a manufacturer's perspective at least, if anything it is probably cheaper than a hydraulic system.

My Landie did "party tricks" with the electric PS system, including self-parking and steering the trailer with the console joystick.  Both fairly useless in practice, but it seems many of today's drivers do like such things, so I think electric PS is here to stay. 

EPS is here to stay, because of emissions or fuel efficiency, which ever side of the coin you want to look at - it takes engine power to keep that pump turning, keep the fluid flowing, which happens as long as the engine is running, and then more engine power when you actually turn the steering wheel, the EPS power draw is significantly less when you're driving in a straight line, which, for most of us, is most of the time.

Electric PAS was the main reason cars were going to adopt 42V* electrical systems about 20 years ago, then motors improved so they could manage with 12V.  Electric aircon is the next holy grail - it eliminates slow refrigerant leakage as there are no shaft seals, and means you can run the compressor at the best speed for the cooling requirement instead of being linked to engine speed.  But at about 2kW power consumption, 12V doesn't cut it.  You'd need enormous cables and motor windings.

*14V x 3; they based it on the voltage with a running engine, not the nominal 12V.