Toyota FRS Electric Power Steering in an A Body

[jetmech442]

Objective:
Integrate a 2014 toyota FRS Electric Power Steering(EPS) system into my ’69 Cutlass, allowing the steering ECU to vary assist levels based on vehicle speed, mph, torque input and steering angle.
Motivation:
This car has always been more of a journey-not-destination thing for me. And as such I'm at the point where the Grand Jeep Cherokee steering box and stock LQ9 pump with Turn One reducer valve just isn't doing it for me anymore. I'd love to give Turn one or Lee a thousand dollars, but I don't have that kind of money, plus getting the known easy solution isn't my thing for some reason, I guess I just like the challenge of integration. I've got a build thread over on LS1tech https://ls1tech.com/forums/conversio...version-2.html where I started, if anyone is interested.
I’ll state here that I am not a CANBUS expert, I’m merely a novice with an Arduino and CANshield that is pulling data from multiple sources and doing his best to put the pieces of the puzzle together. I love discussion and feedback and always am eager to learn from the awesome people here at protouring and my goal is to help others on their path.

So this project, as most of mine do, stands on the shoulders of giants. Below is where the majority of my knowledge came from-people freely sharing what they've learned for the love of cars. Hopefully someone someday will use this to do something even cooler(also kind of assuming that this project is successful in the end, lol). I'm a thermal engineer by day, which means I know lots about temperature and not lots about CANBUS or electronics. I dabble in Arduino, but most of what I do with it is based re-purposing other peoples code-guess I'm trying to say that I don't think this is out of anyone’s ability if they have the desire.
CAN equipment
I am using a Seedtudio v1.2. there is a new version out since I’ve had mine for a while, but I don’ think it does anything significantly different.
http://wiki.seeedstudio.com/CAN-BUS_Shield_V2.0/
This stacks on top of a basic Arduino Uno. And plugs into the car using the OBD-connector and DB9-connector that Seedstudio sells.
There are tons of ways though. I have run into a lot of people who been very successful with the SocketCan, which utilizes Linux and a direct port into a laptop. Since I plan to convert my current rpm/VSS into a CAN message and broadcast, the arduino seemed like the best path for me though.


Different ways to get assist from your unit:
There's several way to tackle this. Some just hook up power(no CANBUS) and have full assist at all times. some hook up what I assume is a pwm circuit and dial in what they want which is the same across all speed levels. My contribution will be(hopefully) adding in the CANBUS communication to the toyota steering ECU and letting the algorithms control assist based on VSS, rpm, steering torque and steering angle. So, as we all know, OEM's spend quite a bit of time tuning the EPS for steering feel. I assume that they spend more time on "feel" for the FRS than they do a Yaris or Prius, so I scooped up a 2014 FRS EPS with ECU. I plan to convert the RPM and VSS from the LS1b GM ECU into CANBUS signals and let it do its thing. That's the plan at least!!!! I'll post more as I make progress, hoping this won't take too long. Below is a quick pic of the EPS in the back seat.



Knowledge sources
So to start with, Waid302 posts in vintage mustang what I consider the best starting place for understanding the project. Its a huge read, but worth it. He provided a ton of pics and diagrams which are enormously helpful-especially if you just want a Prius unit to give full assist.
https://forums.vintage-mustang.com/m...cs-videos.html

dobrostand has a thread in the same forum detailing specifics of the driveability of the system, which led me to believe this might just be worth it.
https://forums.vintage-mustang.com/m...ivability.html

Also on Vintage mustang- Andrewb70, originally known to me as project_GatToGo and who is a huge inspiration to my build, details the specifics of installing in his cougar, but also takes it a step further at getting his dominator to provide VSS to the prius ECU for variable assist. Also pretty much lays out all the details for fab/install that you could ever want,assuming you are skilled with a whizwheelofdeath, lol. Additionaly, he brings up the detail that the ECU needs to run a centering calibration if any of the parts have been mismatched, replaced or otherwise tampered with.
https://forums.vintage-mustang.com/m...s-install.html




I believe those threads should be sufficient to get a Yaris/Prius or Saturn Vue EPS installed and supplying full assist. The nice thing about the Japanese EPS systems is that they supply full assist in default mode if no CAN signals are received. The Vue uses an aftermarket box that dials in "fixed" assist. Lots of people feel fine with that, I might also, but I like being a nerd so I'm looking into supplying the proper CANBus channels.

The next major source of info is some enginerds at the University of Tulsa has published some papers on CANBUS hacking. They provide the engine speed HexID (2C4), and a version of the vehicle speed(610). I'm not entirely sure ID 610 is what the Steering ECU is looking for based on some info I find down below, but we'll get to that. This paper is awesome at showing the methodology for grabbing canbus data and then deciphering it. These guys are the real deal.
http://tucrrc.utulsa.edu/ToyotaCAN.html

Then, Fabio published a youtube video of a camera synced with CANBus data in a 2010 Camry. This allows you to see the structure of the CAN message for RPM (2C4) and Vehicle speed(both “B4” and “610”).
https://www.youtube.com/watch?v=KHRPmjwXF1U


I would say this entire paper is a must-read and is also the most indepth of anything I've found so far. It talks about great details for ford and Toyota steering/braking Canbus interfaces. Specifically, page 41 shows how ID B4(vehicle speed) is not only structured in the way of what bits mean what, but also how to combine them, and the importance of the "checksum" bit at the end of the messages for toyota. If the different nodes don't see the checksum, they will ignore the message all together. I don't know if this is all OEM's or just Toyota.
http://illmatics.com/car_hacking.pdf