My car is behaving exactly like this: Dashboard lights up and it'll only go into neutral. However, on rare occasion, check engine light disappears, engine engages, and I am able drive it. But as soon as I turn it off, it does the same thing. The codes I get is as follows. P0A09 P3000 P0A0D P0AFA C1259 C1310 I've replaced the 12V batter, Hybrid is about 3 years old (40K miles), Redy does not go into "Ready" - it flickers and does not go in. Hybrid fuse is "OK". And as mentioned, on occasion, it does engage the motor and even though the dashboard light stays on, I am able to drive it. Let me know if you have any ideas. I'm really trying to avoid taking it to the dealer. I just don't trust them. I trust mom and pop mechanics more than I trust the dealer. But most mom and pop's don't know how to work with hybrid systems.
The P0A0D code is a very familiar one around here. Means somebody had the safety interlock plug out of the traction battery, and didn't put it all the way back in with the handle slid home. Makes the car do exactly what you'd want it to do with the HV safety interlock out.