Engine will not start, CEL/MWL.

I'm at my wits end on this and need some help.

Car was sitting for a period of about 24 hours, after attempting to turn on the car I got the always unhelpful and misleading "Christmas Lights" (Master Warning Light, Brake, CEL, ABS, etc). Radio and air would turn on but the engine would not.

Doing a quick diagnosis I found that the 12V was not at an appropriate charge, I replaced the 12V but still have the problem. Here's what I've already tried:

• Replaced 12V Battery (Yes, double-checked polarity, 3 wires, and whatever that "tube" is)
  
• Reviewed fuses under the hood
• Checked Fluids (All fine)

I have two and only two codes when I attempt to start the car, C1259 and C1310. I know this is not a problem with the Hybrid battery itself. (Just trust me on this one, I've replaced the Hybrid Battery in the car twice, I know the symptoms.)

I can only assume there is some connection issue I'm missing but I have no clue where. People mention some sort of bolt or wire or something super-vague in other posts but I have no idea what they could be referring to.

Plz Halp.

 

I'm getting 11.9V when powered on. Doublechecked the connections to the posts, the 3 plastic plugs, and both ends of the negative terminal. They're all tight.

Unfortunately no. It is super basic. I'm wondering if the battery was drained completely previously if there's some other way to reboot the system aside from unplugging the 12V.

 

Yep, I've got a crappy little OBD reader. I used to have a copy of TechStream but it no longer functions at all. But right now, when I start it, I only get those two codes. I know the OBD reader is capable of getting the "P" codes, but not any of the proprietary sub-codes.