Need help Warning lights on

The major issue appears to be a high voltage ground fault. This may be due to an electrolyte leak in a battery module. It also might be due to a failed stator winding in the transaxle.

 

C1241 – Do you have the detailed code? Probably it’s just bad/empty 12V battery. But this does also mean that other codes are not as reliable because Prius can generate random codes with bad 12V battery.
C1242 - Do you have the detailed code? Maybe this could be caused by bad 12V battery.
C1310 – This is just caused by other code(s)
U0293 – Commonication problem between HV ECU and ECM. Wiring or either of those control units. Maybe a small change that this would be caused by bad 12V
C1259 – This is just caused by other code(s)
P0AA6 – Has AC been filled with gas that has wrong oil? Or even using equipment contaminated by wrong oil? Prius uses ND oil rather than PAG oil. Or maybe there has been water in the hybrid battery? Water in the back might also cause corrosion in connectors that leads to U0293. If it’s not either one of those it could be your transaxle.

Check the 12V battery first and while at it you see if there has been water in the areas of 12V battery, spare tire and hybrid battery. Detailed code is under freeze frame data on Techstream (which is cheap and good diagnostic tool as Mini-VCI) but probably you should be able to find it with your tool as well.

 

The electrolyte is clear and not very visible. You would have to assume that at least one module adjacent to case corrosion is leaking sufficiently to reach the case bottom. If you see corrosion on the busbar hardware, that may partly be related to module electrolyte leakage.

 

any codes? are you using mini vci?

 

You need to clean each individual module and the inside of the battery case to remove all traces of electrolyte. Then ensure every component is thoroughly dry before reassembling.

Also apply some No-Ox (Electrical Contact Lubricant - Conductive Electrical Grease | Sanchem, Inc.) to your cleaned bus bars (what you called contacts) so they do not re-oxidise.

 

The traction battery has two bus bars, which are the plastic strips containing the copper pieces that you cleaned.

You need to distinguish between two issues: 1) electrolyte leakage and 2) whether the module will accept a charge. It is possible for a leaking module to still be functional as a battery, however if either of those issues exist you need to replace the module.

And even after going through all that work, if the OP leaves leaking modules in the battery case, then the problem will eventually recur.

 

I doubt this is the problem, but If it hasn't already been replaced now would be a good time to change the transmission fluid.

 

Each ECU can log its own DTC. What DTC are logged by the hybrid vehicle ECU and the traction battery ECU?

 

The Prius has multiple electronic control units (ECU). Each ECU can log diagnostic trouble codes (DTC). The first photo you posted shows DTC logged by the skid control ECU while the second photo shows DTC logged by the gateway ECU.

Although those codes are interesting, what you need is to see what DTC are logged by the hybrid vehicle ECU, traction battery ECU, and engine ECU. Any such codes will help to determine the root cause of your car's problems.