Non-Toyota OBDII scanner on NHW11

I'm wondering what the limits are on what can actually be accomplished using a NON-Toyota OBDII scanner on an NHW11. (NHW11 was pre-CAN, right?)
I know I could do pretty much everything with a Toyota scanner ... or I could use the money for a spare NHW11 to drive in case of a problem with this one.

There are some reasonable-looking scanners that say they do support various Toyota enhancements. What are some of the things they can do, and CAN'T do?

I assume they could see all of the CARB DTCs and Toyota DTCs in the ECM,
and they might be able to see some parameters and freeze frame data. If I had to look up numbered parameters in a list somewhere instead of having the names displayed, I wouldn't so much mind that (assuming somebody has such a list).

Can a non-Toyota scanner pull DTCs or parameters from any of the other ECUs, like the HV, in an NHW11? Can it see the other ECUs at all? Again, I wouldn't mind having to look up some numbers instead of having the names shown, but I'm wondering what communication is even possible. If a scanner calls itself bi-directional, is there any way to do some of the procedures shown in the manual as "Toyota scanner only", maybe by knowing the right numeric parameter ID to frob?

Obviously I'm just getting started with this, so I'm sure some of you have learned a lot about this already.

Thanks,
-Chap

 

Thanks Patrick!

That looks like a very good product and I hadn't known a thing about it. It also looks like I'd need a bit of luck to find somebody with one to sell. I'm debating whether I should just get one that's less Prius-specific but more readily available, just so that I have something to look at if I have any issue arise while I'm waiting for luck to strike on finding an ecrostech. Did anybody else make an OBDII scanner able to see HV or battery ECU codes?

-Chap