I just googled it and it looks like it's on the front facing side of the engine block in most all Toyotas... So I suspect this photo I found is likely accurate despite being a Gen3 engine and not a gen2.
I Googled it as well but like you, only found Gen3 and didn't even look at it. Figured someone here would know for sure. Thanks. I'll look there.
Well, I've never had to take a Gen2 apart but the service manual had this to show. That's as "sure" as I can get. (The torque specification is important for this sensor) Posted via the PriusChat mobile app.