Any EPAS fans out there?

So I posted this in my own install thread, but I think the return to center issues stem from the controller running in failsafe mode. I've been running my install for a little over a week now and finally got the CAN messages sorted out this past weekend for engine rpm and vehicle speed. It makes a noticeable difference in how it returns to center. I think even if you have the non-ABS unit that just uses the VSS input it might still want to see engine RPM over the CAN bus.

I would assume the 100% aftermarket kits with their own custom controllers would not be as prone to this issue. I'm pretty sure some of those kits include steering angle sensors as well, so they would know where center is and be able to "push back" there. A lot of the junkyard units only have torque sensors on them, so if they do get any angle info it would also be over CAN. I found a little article about Toyota EPS that talked about the different style of torque sensors and motors they used over the years and it talks about getting information over CAN, but it's unclear exactly what all the controller is listening for. There is plenty available on the bus to listen to, but it's hard to tell which controllers actually use that info. It wouldn't surprise me if the Toyota EPS controller actually wants to see a steering angle sensor input. I don't think it throws a fault if it's missing though, so hard to say for sure. In general the article just said it got information from the "anti-skid" ECU. It talked about cutting out assist if it saw excessive yaw rate (like a car starting to spin), and I think you can also actually command the units to actively steer (like lane keep assist). So there is potentially a lot more on the table with these than the way people are using them in classic car swaps, but a lot of it is just "guess and check".