Why is my steering hard without the car reading any code

It's probably your scanner. Most cheap scanners are only good for generic codes; you need to spend a lot more to get a scanner that isn't a waste of time (usually ~$150 or so; make sure it can pull OEM codes). Look into a scanner like this instead.

That said, it's usually a bad power steering motor or low power steering fluid. Some newer cars no longer use power steering fluid and only use electrical power steering, but many Toyotas still use fluid and not fully electric power steering. If it's losing fluid, you'll need to trace where the leak is coming from.