Darn,I assume you mean ELM327 as well? Then very likely a HV leak P3009 as someone already mentioned. That is one of the few codes I haven't been able to pull up on Torque. You're going to need the tech stream app and mini-vci cable Since you just changed the battery, check kenoarto's link on the hatch leak.
Do you have the Prius specific PIDs loaded? You will also need to have the Pro (paid for) version of Torque to load the additional PIDs With the lights and Icons you have there ARE codes, you're just not seeing them at the moment. The code was changed to P0AA6 on Gen 2 onwards. But more importantly is the sub-code other than 526) is more useful to pinpoint where the problem is located. You are looking for 611, 612, 613 or 614. Not sure if you can get the sub-codes with Torque as I don't use it myself.
A month ago I too had a PLock Malfunction message on my v and the car refused to start. Played with the Park and Start buttons for a while. Very unhelpful message and the owner's manual and Toyota's Emergency service was little help. It occurred after driving 3 hours but with a 5 year old battery. They called a tow service who seemed to rock the car back and forth and play with the buttons and it started. Second time in my flat surface garage 400 miles, dozens of starts and weeks later. Jumped that time and it worked. Then 3 days later in a Walmart parking lot. But fortunately across the street from the dealer I bought the car new from. They went over and it just started. This after me fiddling with everything I could think of including rocking the car back and forth and jump starting. 40 minutes later it just started and they said they did nothing. They took it into the shop and put it on their computer and didn't see a thing but the technician did see one PLock failure. Called in the heavy hitters (from the region or some such resource to the dealer's service department) and they followed the diagnostic tree and eventually replaced the PLock actuator' The Actuator looks to be the motor that moves the pawl that is inserted into the transaxle that locks the "transmission". Picture posted in the v section of the forums (search for PLock). Can't tell you the cost as it was covered by a drive train warranty. There were two actuators in the part inventory, took 4-5 days to get it. This when Amazon can do 1 day if necessary. Doesn't seem common as there were no other PLock referencing forum messages for any car when I looked. The "park on flat surfaces" message seems to be a bit late as when the error occurs you are already parked and it is a bit late to follow the message. I do think it possible that you can cause damage to the assembly by using Park while the car is moving. I'm trying hard when I have to stop in a hill to use the foot parking brake first while still applying the brake pedal, get the car totally stopped and then use Park and Stop.
